Signs of Winter 2: Super (and not so super) Moons

NASA, Wikimedia Commons

Photo by NASA, Wikimedia Commons

In mid-November our full moon was a “supermoon.” The moon was closer to the Earth than it had been in 70 years, and the truly unexpected feature of this November, 2016 full moon was that we actually see it! Cloudy skies are the rule here in Western Pennsylvania especially during our drizzly, autumn season. The November “supermoon,” though, looked like almost every other full moon that I have seen. I couldn’t say that it was bigger or brighter than normal (the 7% increase in size and the 15% increase in brightness were hard to discern).

A “supermoon” occurs when the moon is at the perigee (closest point) of its elliptical orbit around the Earth and is simultaneously in its full phase. When the moon is full at its apogee (most distant point) it will be 14% smaller and 30% less bright than the perigee “supermoon.” You would need to view these two moons side by side to really appreciate their differences, though (now THAT would be an exciting astronomical (and probably even astrological!) event! If it happened, though, it would probably be too cloudy to see it).

On average the moon is 238,000 miles away from the Earth. At the November 14, 2016 perigee, though, the moon was only 221,524 miles away from the Earth (and at its next apogee on November 27 it was 252,688 miles away. Quite a fluctuation in distance!

Photo by Joneboi, Wikimedia Commons

Photo by Joneboi, Wikimedia Commons

Ocean waters rise and fall under the gravitational tugging and pulling of the moon (and the sun!). The twice daily coastal changes in sea level (the tides) are reflective of their oscillating, gravitational influences. When the sun and the moon line up relative to Earth in space their influence on tides increases. At “new moon” the sun and the moon are on the same side of the Earth pulling together, and at “full moon” they are on opposite sides of the Earth having a great tug-of-war on the oceans. Both extremes will cause the tidal movements to be exaggerated. When the moon is at its apogee its influence is decreased and tides will not rise as high (“neap tides”) and the difference between high and low tide will be reduced. When the moon is at its perigee, though, it’s influence will increase and tides will be quite high (“spring tides”) and the differences between high and low tides expanded.

The gravity of the moon (and sun) also tugs and pulls on the Earth’s land masses. The continents themselves move (very slightly) when the gravitational forces are combined or intensified. There is even a slight increase in tectonic activity (earthquakes!) when the sun and the moon line up in their “new moon” and “full moon” configurations.

Photo by Benh Lieu Song, Wikimedia Commons

Photo by Benh Lieu Song, Wikimedia Commons

Many animals (including humans) alter their behaviors as the moon goes through its phases. Many of these described changes can be explained by the increased light of the full moon or the intensified darkness of the new moon. For example, African lions change the timing of their hunting patterns when the moon is full. The lions switch from night hunting to day hunting in response to their prey hunkering down at night to avoid exposing themselves in the over-illuminated savannahs. A consequence of this temporal shift in activity is that the lions now are more likely to encounter humans (and the incidence of lion attacks and human deaths increase!).

European badgers tend to mate during the nights of the new moon. This is because badger mating takes over an hour and a half for full completion. On nights with any moonlight at all the mating badgers (who apparently must really concentrate on the mating task before them!) are increasingly vulnerable to (and oblivious of?) predators.

Photo by J. Gentry, Public Domain Pictures

Photo by J. Gentry, Public Domain Pictures

Corals release massive clouds of sperm and eggs in conjunction with the full moon. Timing this release as total group effort makes the probability of a sperm finding a suitable egg greater and thus increases the reproductive efficiency of the entire population.

The moon, though, may also affect organisms more subtly than simply as serving as a light source. In his 2006 paper published in the on-line Polish medical journal Postepy Hig Med Dosw, M. Zimecki speculates that the gravitational influences of the moon during its waxing and waning cycles may affect the synthesis and release of both hormones and neurotransmitters which in turn alter the functioning of a variety of organ systems (including the immune, the reproductive and the cardiovascular systems) in many types of animals (including humans). In birds, the daily fluctuation in melatonin and corticosterone stops during full moon phases. In insects, the lunar cycle alters hormone synthesis and developmental processes, and in lab rats, sensory systems (especially taste) and pineal gland functions and anatomy change with the phases of the moon. The immune systems of mice are also inhibited during full moon periods.

During full moons both emergency rooms at hospitals and at veterinary clinics see increases in their patient loads. More accidents occur but there are also more cases of angina, heart attacks and strokes. Not all of these changes are attributable to just the increased light in the night sky! Brain activity changes, and more stress hormones and neuropeptides are synthesized. We all go a little “werewolf” whether we know it or not when the moon is full.

Photo by B. Rostad. Flickr

Photo by B. Rostad. Flickr

Antlions are glorious little insects that are great fun to watch and play with. These insects have larvae that often called “doodlebugs.” Doodlebugs make ingenious funnel-shaped, pitfall traps in sandy soil and hide in a tunnel at the center of the trap waiting for unsuspecting prey (especially ants!) to fall in. Doodlebugs make bigger funnels and wider, deeper holes when the moon is full. And, they even do this when they are locked away in the total darkness of a laboratory! There is something about the moon, and not just the moonlight that is affecting these doodlebugs.

There are some ominously named full moons coming up. The “Cold Moon” of December, the “Wolf Moon” of January, and the “Snow Moon” of February. They will get us through the winter until at last the “Sap Moon” of March brings the rising sugar maple sap of spring (and all of the maple syrup, too!). Hunker down everyone! We’ve got the coming holidays and then our long trek through winter!

 

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Signs of Winter 1: New (and Continuing) Birds

 

Photo by D. Sillman

Photo by D. Sillman

I have been watching my bird feeders for the “birds of winter!”

The first of these seasonal arrivals was on Saturday, October 29 (and looking back at my notebooks from previous years, this species always shows up in Apollo sometime in the last three days of October!). Scratching around in the fallen seed under my sunflower seed feeders were three northern juncos. More, I am sure will come soon. Their departure in March or April will be one of our important “signs of spring.”

Northern juncos are small, dark-colored sparrows with a long list of very descriptive common names including “dark-eyed junco,” “slate-colored junco,” “snow bird,” and “winter finch.”  It is a very common bird at almost any winter bird feeder throughout the United States, and it over-winters in almost all of the lower forty-eight states (and down into northern Mexico). The junco has an equally broad summer/breeding range across Canada and Alaska, in the mountains of the western U.S., throughout New England, and down the Appalachian Mountains into northern Georgia. In Pennsylvania, in addition to winter populations of “bird feeder” Northern Juncos, Deborah and I have observed large, summer populations of this species in the mixed hardwood forests of the Allegheny National Forest in the northwest section of the state.

Flocks of fifteen to twenty individuals form in the autumn and winter. These flocks may include several of the northern junco sub-species and also several other species of sparrows and maybe even bluebirds.  These flocks gather together thirty minutes before sunrise and disperse forty-five minutes before sunset each day. Foraging success for each individual is significantly increased when they participate in one of the groups. An individual junco tends to stay in a single foraging flock for the entire winter.

The arrival of the juncos in Western Pennsylvania has both positive and negative implications: a handsome bird has returned to grace our lawns and fields, but the cold, snowy months of winter are almost upon us!

I am keeping my eyes open this year for pine siskins! One of my biology students is writing a species paper about them for our “Birds of Pennsylvania” blog site (which will go live sometime in mid-December!). Lynn Ramage over in Ford City spotted pine siskins for her count in the Great Backyard Bird count a couple of years ago, and I could use an extra species or two on my list. I have put out a thistle feeder in my front yard to try to draw them in. We’ll see if the winter is harsh enough to drive these northern birds down into our area!

Photo by D. Sillman

Photo by D. Sillman

Also on Saturday, October 29, a flock of about thirty cedar waxwings landed in the branches of the tall black locust tree at the back of my property. Western Pennsylvania is in the year round habitat zone for waxwings, but they may migrate south if temperatures get too cold or if food supplies (berries and fruit) run low. Some flocks may fly all the way to Costa Rica or Panama to find suitable winter habitats. Always found in large flocks of thirty to one hundred birds, waxwings may form migratory flocks numbering in the thousands.  The flock that visited my

Photo by D. Sillman

Photo by D. Sillman

yard was probably after the crabapples that were still hanging on in the higher branches of crabapple trees (the deer had stretched up to eat all of the lower ones!). The birds hung around and fed for a couple of hours and then flew on. The waxwings are a wonderfully social bird with many described individual behaviors involving sharing food and other resources with the other birds of their flocks. Another of my students is writing a species page for our “Birds of Pennsylvania” blog on these gentle, gregarious birds! So watch for it in December!

Photo by D. Sillman

Photo by D. Sillman

Deborah and I went up to Harrison Hills Park on November 6 to check out our bluebird boxes and make sure that they were in good shape for the winter. Two bluebirds followed us around the High Meadow and kept a close eye on what we were doing. Both of the birds were males, although the intensity of their blue plumage was muted with the season.  Three of our boxes (last checked in late September) now had empty house wren nests in them, and one box had an empty tree swallow nest. We cleaned out the old nesting materials and, hopefully, made the boxes acceptable to the overwintering bluebirds. Most bluebirds in our region migrate at least short distances to more moderate climate zones that have a richer supply of seeds and fruit for the winter. A small percentage of our bluebirds, though, if provided suitable shelter and adequate food supplies, will spend the winter here. They run the risk of death by starvation or freezing in a severe winter, but they can reap the benefit of energy savings from eschewing migration and having the first shot at selecting local breeding territories in the spring!

Last winter Deborah and I came across a large flock of robins in the shrubby woods around the pond in Harrison Hills. The bushes and vines of this woodlot were full of berries and represented a substantial winter larder for these fruit loving birds.

Deborah has seen several bluebirds this November on her walks through the cemetery here in Apollo. They must be nesting in the line of old trees along the ridge over the river on the back edge of the cemetery property. These trees are in a very natural, untended state and are full of broken limbs and standing dead trunks. All of these potential tree holes generate an outstanding natural nesting site for any cavity nesting bird species.

Photo by D. Sillman

Photo by D. Sillman

During the first week in November the white-throated sparrow started singing just before dawn. I haven’t heard these songs since early summer! The singing became a real chorus on November 7 with three or four males all joining in together! They sang to Izzy and I while we took our early morning walk. I have read that this species sings in the winter (unlike most birds who primarily sing during mate selection or territory marking in the spring), but I have not been able to figure out why!

And finally, in big bird news from Apollo, PA: we have bald eagles! Three times in the past two weeks Deborah and I have seen bald eagles flying over our hillside. One was coming up from the Kiski River, one was racing along our ridge top heading east, and one was flying north out over the surrounding hills. This species has made an incredible come back here in Pennsylvania during the 34 years I have lived here! There are almost 300 nesting pairs of bald eagles in Pennsylvania today (compared to just 3 pairs 30 years ago!). Internet-linked nest cameras generate a continuous record of their breeding successes (and, sadly, their tragedies, too), and increasingly we are able to get glimpses of their beauty and grace as they fly over our everyday spaces!

So, the birds are active even as the temperatures drop and the snow is starting to fall. Get out and enjoy them, or at least find a nice window in your warm, dry house where you can sit back and watch the show!

 

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Signs of Fall 12: Our Other Best Friend

Taz and Friend Photo by D. Sillman

Taz and Friend
Photo by D. Sillman

People have very strong opinions about cats, and in my experience the numbers of people who have positive feelings about cats far outnumber those who have negative feelings about them. The interesting thing about these likes and dislikes, though, is that they may be the result of absolutely the same set of facts and observations! The same feature of a cat or its behavior may cause some of us to swoon with pleasure but then cause others of us to turn away in disgust. Unlike many of our political and social problems, we don’t have “different sets of facts” when it comes to cats!

So what do we know about cats?

The domestic cat (or “housecat”) was named Felis catus by Carlous Linnaeus in 1758.   This scientific name went through a number of very speculative changes over the next two and a half centuries as the biological identity of this familiar species was debated. For a while the housecat was included as a sub-species of the wild cats (Felis silvestris) of Europe (F.s. silvestris) and Africa (F.s.lybica) from which it had undoubtedly evolved. More recently, however, it was returned to its own Linnean species designation: F. catus.

African wild cat, Photo by Gurtuju, Wikimedia Commons

African wild cat, Photo by Gurtuju, Wikimedia Commons

The six (or, possibly, seven) living species of the genus Felis all trace their evolutionary lines back six or seven million years to a common, Asian ancestor.  The natural ranges of these Felis species include almost all of Africa, Europe, the Middle East and central and southern Asia. All of these cats have very similar sizes, conformations, and habits. Felis catus as a domesticated partner of humans has spread widely over most of the Earth but has retained the generalized appearance and behaviors of its closely related fellow cat species. Put a wild cat from Africa (like the one pictured above) next to a domesticated cat from Pennsylvania and they would look overwhelmingly alike.

How cats came to be domesticated is a subject of intense speculation. It seems logical to assume that humans would benefit from the ability of cats to catch and kill vermin (especially rodents), but whether this symbiosis was from an intentional act of domestication or simply the inadvertent consequence of wild cats exploiting the vermin-rich habitats created by people and then sticking around to take advantage of the weather –resistant, human constructed habitations is probably unanswerable. Wild species of Felis do display a ready tendency for at least semi-domestication and have a high tolerance toward the presence of people. So it is indeed possible that wild cats just got close to some of our ancestors and stuck around for the food and for the shelter. The nature of the human/cat symbiosis is possibly less mutualism than it is commensalism!

Photo by M. Hamilton

Binx and Mora    Photo by M. Hamilton

An often repeated story in which cats and dogs (and sometimes even children!) are compared describes a hypothetical situation in which one of these organisms is abandoned in an unfamiliar place (just pick the ecosystem: a forest, a farm, a prairie, or the seashore).  In the story, when the abandoning pet owner (or parent) subsequently (and hopefully promptly!) returns, both the dog and the child greet the returning person with great energy and affection (not to mention relief!). The abandoned cat however, in this old social myth, has taken off to explore the wild, new habitat and has begun to fend for itself and totally ignores the returning “owner.”

Now this story is much more fiction than science. I am sure that many dogs (and I can think of two that I have owned over the years) would have run out into the new, unexplored place of their abandonment with uncontrolled enthusiasm and only returned to their owners after many hours (or days) of calling and searching. I am also quite sure that some cats, if transiently abandoned somewhere, would come running to the sound of their owner’s call. I don’t even want to think about the child part of this story! Let’s just say that I think children were added to this tale by the dog-lover who first came up with this foolishness in order to add some emotional tone to the proposed dog results!

Photo by D. Sillman

Mazie      Photo by D. Sillman

Daniel Mills of the University of Lincoln in the U.K. is a widely published animal behavior expert. Mills has conducted experiments that play with the three components of the above social myth (dogs, cats, and children) and expose them each to unfamiliar surroundings and the presence of reassuring owner (or parent). Mills has found that dogs and small children demonstrably attach themselves to their owner or parent when they are placed in an unfamiliar situation. Cats, however, do not turn to their owners when placed in these same unfamiliar places. Instead, cats will focus on the surroundings and (“heartbreakingly,” according to one reporter writing about these experiments) ignore their owners.

Mills conclusions are that dogs and children “love you” and cats do not!

These experiments were featured on a BBC television special that was broadcast in 2013. I have recently searched through a number of science journal article data bases looking for the published descriptions of these studies, but, although as I said at the onset of the discussion Mills has numerous journal publications on a wide range of animal behavior topics, these experiments have not yet been described in a refereed journal.  They have been, though, widely quoted especially in on-line articles. For example in Vox on October 16, 2014 an article entitled “What Research Says about Cats: They’re Selfish, Unfeeling, Environmentally Harmful Creatures” (I guess that the reporter wanted to put his entire thesis statement in his title!) featured these experiments and repeated the social myth that I described a few paragraphs back.  The author, obviously an unbiased arbiter of the truth, went on to cite a variety of scientific sources to back up his underlying thesis that cats are evil!

Boz and MaGoo Photo by D. Sillman

Boz and MaGoo
Photo by D. Sillman

Which gets us back to our original idea: people love and people hate cats for exactly the same reasons. Domesticated cats look just like wild cats (so they are either beautiful creatures or wild animals masquerading as pets). Humans did not choose them for domestication, instead they chose us (so, they are wonderfully independent, or they are aloof and ungrateful). Cats don’t seem to notice us, they pay more attention to their surroundings than to us (so, they are curious and lively, or they are arrogant and conceited). Cats don’t miss us when we are gone or act happy when we come back (ah, they are independent and not needy like a dog, or they are sinister parasites who think that they own us!).

I take the positive side of these cat descriptions. Cats are elegant, glorious creatures full of surprises and rich rewards! They are not dogs, though. A cat has a different kind of bond with its human, and it is worth it to get to know a cat in order to assess how our co-evolution is progressing!

 

 

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Signs of Fall 11: Our Best Friends!

Kozmo (1999-2013) Photo by D. Sillman

Kozmo (1999-2013)
Photo by D. Sillman

I have wanted to write about dogs for quite a while. I am, very definitely, a “dog person,” and I go out of way to interact with dogs anywhere I might meet them. I have had over all of my 64 (soon to be 65!) years only a small, cumulative number of months when I have not had a dog of my own. I can say “Can I say ‘hello’ to your dog?” in five languages! The only thing that I might be more poly-lingual about is ordering glasses of beer or wine! There was a great flurry of evolutionary and genetic papers published this past summer about dogs: very complex stuff, but worth working through to be able to talk about our best friends.

So where did dogs come from?

Genetically there is no doubt that dogs arose from wolves. There has been, however, a great deal of controversy about where and when that dog/wolf split occurred.

Shiga 1975-1993 Photo by D. Sillman

Shiga (1975-1993)
Photo by D. Sillman

A paper published last year (June 1, 2015) in Current Biology analyzed the DNA of dogs and wolves and determined that the split between the two occurred about 30,000 years ago! This very ancient divergence challenged the prevailing notion that dogs developed as a species and bonded with humans about 10,000 years ago just as people were inventing agriculture and giving up their nomadic, hunter-gatherer life style.

This search for the temporal origin of dogs was also the topic for another research group that examined the DNA from dogs that lived 14,000 to 3,000 years ago. This group concluded that there was not just a single deep past origin of dogs. This study published in Science (June 3, 2016) showed that there were two distinct lineages of modern dogs that evolved independently from wild wolf populations. These observations (which placed the divergence of the two dog lines between 14,000 to 6,400 years ago) indicated that dogs were domesticated at two separate times and in two separate places (once in Europe and once in Asia) and that only in very recent centuries have these two lineages been recombined.

Izzy (2014-present) Photo by D. Sillman

Izzy (2014-present)
Photo by D. Sillman

So dogs have been with humans since before agriculture, and they were so important to people that they were, and this is without precedence among any of the other animal species that humans have tamed, domesticated twice! To me, this helps to explain why I feel that having a dog around is not a luxury but an absolute necessity!

So how does an organism go from being a “wolf” to being a “dog?” What is the nature of this transformation?

Wolves, like other wild animals run away from or lash out violently when approached by humans. The central cause of this fight or flight reaction is a massive release of stress hormones (especially adrenaline) that then triggers the physical behaviors. The flight distance (the distance at which an approaching human will trigger flight) or the critical distance (the distance at which protective/aggressive behaviors are triggered) that an animal exhibits vary with the animal’s experience, with its environment and also with its genetic makeup. Some individual animals are more tolerant of humans, you can get closer to these individuals and you may even be able to touch them without triggering their stress response!  These are the individuals that could be selected to build a “tame” (or “domesticated”) population! Also, young individuals of many species lack the flight or fight stress reaction to people. Possibly selection of “tamable” individuals of a species is actually the selection of individuals who retain the physiological (or emotional) characteristics of their youth!

Danny (1983-1999) Photo by D. Sillman

Danny (1983-1999)
Photo by D. Sillman

There were some very famous experiments conducted in Russia back in the 1950’s involving the domestication of another canid, the red fox (Vulpes vulpes).  Dmitri Belyaev was the director of the Central Research Laboratory of Fur Breeding in Russia. The silver fox (a variant of V. vulpes) was being bred at the laboratory and Belyaev wondered if he could select for a tamer, more easily handled animal. He had his associates evaluated the foxes in each litter for positive behaviors toward humans up to the onset of their reproductive maturity. Those individuals who were friendly to and calm around people were then allowed to breed. Within a few generations, a larger and larger percentage of the kits were “people friendly,” and soon not only the behaviors but also the physical appearances of the tamed foxes became more and more “dog-like!” The tamed foxes had floppy ears, shorter tails, and wider and shorter skulls. Their coats became curlier and took on a wider array of colors and patterns. The tame foxes also lost the distinctive “musky” smell that commonly occurs in wild foxes. The tame foxes also wagged their tails, and whined and barked like dogs!

Belyaev attributed many of these physical and physiological changes to a decline in adrenaline and other stress hormones and also to changes in neurotransmitter levels in the brain. He had “invented” a new domesticated canid! Possibly a similar selection process, carried out almost inadvertently in the frozen, Ice Age wastes of northern Europe and Asia, went on to facilitate the transition of wolves to human-loving dogs!

Izzy Photo by D. Sillman

Izzy (again)
Photo by D. Sillman

This fall there was an article in Scientific Reports (September 29) that looked at some specifics of the genetics that might have been involved in dog domestication. In this study a population of 430 laboratory raised but untrained beagles were presented devices that contained small pieces of food. Some of these devices were easily opened while others were functionally un-openable.  The researchers measured the intensity of the orientation of the dogs to human beings in their attempts to get help to open the difficult devices. Some of the dogs, frustrated by these devices turned to supervising humans with very obvious behavioral and auditory signals and “asked” for assistance in obtaining the food treat. Other dogs ignored the human supervisors completely and simply gnawed on and scratched at the food filled device.

Almost half of the dogs in this study fell into one of these two behavioral extremes. Analysis of the DNA of these dogs showed differences in gene markers found on their Chromosome #26. Approximately 30% of the dogs that actively turned to humans for help had very distinctive DNA base patterns in genes that in humans have been associated with many interactive and social behaviors! Possibly, these dogs were genetically predisposed to include humans in their social spheres (an absolute requirement for initial domestication!).

Dogs and dog perceptions have been described in several other, recent research articles. One (in Science August 30, 2016) used MRI scanners to determine how dogs’ brains process both words and emotional intonations. These researchers noted that verbal commands had to be accompanied by appropriate tones of speech in order to stimulate pleasure centers in the dogs’ brains! Another article (in The New York Times (October 10, 2016) described a dog’s sense of smell and compared the detail and importance of the odor map that a dog mentally generates as they move through the world to our own visual map of the world. Dogs create a continuous, three-dimensional matrix of olfactory sensations and orient to and interact with this scent reality in ways that we can only begin to imagine!

So, go out and do something with your dog today! If you need to, just borrow one. Your genes (and their genes) will definitely thank you!

 

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Signs of Fall 10: Return to Todd Sanctuary

Photo by D. Sillman

Photo by D. Sillman

It was Sunday morning, one day past the Ides of October. It was cloudy but already almost seventy degrees. It was a perfect day to go for a mid-Fall hike.

We wanted to get away from the broad, rails-to-trails pathways that we have been walking and biking all summer, so we fell back on our old reliable hiking site near Sarver in southeastern Butler County, the Todd Nature Reserve (formerly called “Todd Sanctuary”).

The Todd Nature Reserve is a rocky, stream crossed, 176 acre site owned and maintained by the Audubon Society of Western Pennsylvania. It has been, since Deborah and I moved to this area in 1983, one of our favorite places to hike. There are five miles of crisscrossing trails including a two mile (although it always feels longer than that!) “Loop Trail” that circles the site’s perimeter, and a number of shorter trails (with descriptive names like “Hemlock,” “Indian Pipe,” “Pond,” “Warbler,” and “Polypody”) that interconnect fern capped rock cities in densely vegetated copses with the human constructed pond (built in 1969). As you walk through Todd you go from stream beds to ridge tops and back again through young to middle-aged hemlock stands and a variety of mixed hardwood forests

Photo by D. Sillman

Photo by D. Sillman

We have had some great moments out on these trails! I remember carrying each of our children first in denim Snuggly Packs and then, as they grew, in metal framed, backpack carriers. I also remember letting them start our hikes by walking on their own and then ending up hoisting them on my shoulders after a few miles. I also remember standing quietly on a trail while a gray fox walked toward me oblivious to my presence until I said “hello, fox!” (or something equally brilliant!) and then watched him disappear into the surrounding brush. We once found a hen turkey on her nest right in the middle of one of the trails, and once we found a black bear footprint in some soft mud of a trail and spent the rest of our hike hearing imaginary bear snufflings and rustlings in the dense woods around us!

We have spotted numerous warblers in the spring and in the fall here at Todd and enjoyed the company of many garter snakes and black snakes. It seems on every hike that we come across deer standing watchful guard along the trails, too. Back in the early 1990’s, we experienced the full force of the gypsy moth population explosion along these trails (The Audubon Society chose not to use any pesticides in the reserve, so the caterpillar numbers grew unchecked!). We had to wear hats when we hiked because of continuous deluge of gypsy moth caterpillar feces as the larvae worked their way through the tree canopy and steadily defoliated the reserve’s oak trees. The infestation, though, burned itself out without human intervention, and very few oak trees were lost.

We pulled into the reserve’s gravel parking lot about 11:15 am and were surprised to see ten cars already parked there. Usually, Todd is only lightly visited and the parking area is empty. Could there be something going on today? We only saw, though, two other people out in the woods (actually they were sitting on a bench on the porch of the Naturalist’s Cabin at the start of the trails). All of the other people were well hidden out on the labyrinth of trails. When we got back to parking lot two and a half hours later, there was only one other car remaining.

There were still a few fall wildflowers blooming along the trails (white wood asters lit up the hike down to the cabin from the parking lot), but mostly the understory plants were settling in to a late fall senescence.  Color along the trails came from a thickening mat of freshly fallen leaves (splotchy red and green leaves of red maples, yellow leaves of black cherries and yellow birches). Occasionally a still green leaf fell from one the tall red oaks and arced its way, back and forth and back and forth in the light breeze, falling down through the dense branches of spice bush and multiflora rose until it landed, without a sound on top of the growing leaf cover.

Photo by D. Sillman

Photo by D. Sillman

Acorns pelted down on us steadily as we walked along. This must be a good year for red oak acorns! Next year, then, should be a good year for wild turkeys, gray squirrels, and deer! Lots of high calorie food to help them through the long winter! In some places there were so many acorns that it was hard to walk!

In the clearing between the cabin and the start of the Loop Trail (and all up the graveled trail that runs to the cabin) is a continuous and very dense stand of poison ivy. The leaves are starting to fade from their deep summer green, but they are still thick and resinous and seem to glow as they reflect and concentrate the dim sunlight. I don’t see any berries on the plants. They must have been picked clean by hungry birds!

Freshly emerged mushrooms add to the textures and colors of the exposed soil and the fallen branches and logs. We have enough recent rain to trigger a coordinated emergence of the mushrooms and their whites, reds, yellows, and browns stand out against the paler, fallen leaves. There are rustlings under the leaves, too. Everything from crickets to chipmunks to forest millipedes scrambling about on the brittle surfaces looking for food, looking for mates, or looking for a good place to wait out the winter.

The trail is, as always, rocky and difficult to walk upon. You have to keep your eyes on your feet to avoid turning an ankle or stubbing a toe. So many trails in Pennsylvania are like this! In his book “A Walk in the Woods” Bill Bryson refers to the Pennsylvania section of the Appalachian Trail as “the place where boots go to die!” You need to stop occasionally as you walk along in order to look around and keep track of trail markers and generate even a general sense of direction. While we are walking all hunched over, staring at the ground, I imagine the surrounding underbrush to be full of animals watching us with great curiosity. “What odd creatures,” they must be thinking,“ to plunge through the woods so noisily without even looking where they are going!”

Photo by D. Sillman

Photo by D. Sillman

We stopped at the pond and threw some bread to the fish (all of whom were hidden under the almost continuous cover of lily pads). Green frogs jumped at each piece of bread. The frogs just blink at the bread, though, and then swim away. We watch one green frog stalking a female dragonfly who is busily dabbing her ovipositor onto the open water near the shore. You could feel the logic of the frog: maybe the dragonfly is so focused on laying eggs that she won’t notice a clumsy, slow moving frog angling in for a leap and a grab? But just as it seemed the frog would lunge up after its meal, the dragonfly lifted up and flew away.

We spend two and a half hours wandering around the trails at Todd. There is something so peaceful about being in the woods walking on a narrow, wandering trail with only the sights of your immediate surroundings and only the sounds of your footfalls to fill your mind! We get back to the car tired but well rested, ready for whatever is coming next.

 

 

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Signs of Fall 9: Time is Honey

Photo by I.Tsukuba, Flickr

Photo by I.Tsukuba, Flickr

The title of this week’s post is taken from Bernd Heinrich’s remarkable book Bumblebee Economics (full quote: “to a bee, time is honey”). I was reminded of this quote when I read an article published a few weeks ago (Oct 7, 2016) in the New York Times (“Six Scientists, 1000 miles, One Prize: The Arctic Bumblebee”).  But, I will get back to that in a minute!

Over the past eight years I have written about both domesticated and wild bees a dozen or more times. There are many reasons why I frequently return to this topic: 1. Bees are most people’s favorite insect (in fact, bumblebees have been called the “pandas of the insect world!” (They are big and fuzzy and cute and move slowly enough for us to clearly see them (and, if necessary, to get out of their way!)), 2. Bees are vital in the production of human food (they not only use their “time” to make honey but also (according to Dr. Gabriola Chavarria the former Director of the Natural Resources Defense Council’s Science Center and a Science Advisor to the Director for the U. S. Fish and Wildlife Service) pollinate 30 percent of the world’s crop plants and 90 percent of the world’s wild plants (as E. O. Wilson once said, we should say “thank you” to a bee after every third bite of our food), and 3. Bees are in serious trouble (due to climate change, pesticide poisoning, loss of natural habitats, and rapidly spreading parasites and pathogens).

These three big points energize the scientific discussion of bees! Many studies are being conducted that explore the biology and ecology of these incredible insects, and many papers are published each year describing new aspects of or new perspectives on their lives. I keep a file folder on my desk top entitled “Bees” into which I put new articles that I find in both scientific journals and also major newspapers. When it fills up, I feel compelled to write!

Which cycles us beautifully back to the arctic bumblebee and the brilliant article about it from the Times!

Photo by USFWS (Public Domain)

Photo by USFWS (Public Domain)

In the arctic many insects rely on long, extended and frequently interrupted life cycles by which they eke out their existences and finally accumulate enough resources and energy to accomplish reproduction in the harsh environment and extremely short individual growing seasons of the far north. Arctic bumblebees, though, do not have the luxury of stretching out their life phases over several truncated growing seasons. These bees must accomplish all of the energy gathering, growth, and reproduction in the limited weeks of a single, arctic spring and summer!

So up on the northern rim of the world, these bees have had to develop ways to generate and retain body heat even when the outside temperatures are near freezing. Many of these adaptations are very logical: metabolically they can generate a vast amount of body heat from the contractions of their muscles (an arctic bumblebee can get its body temperature up to 95 degrees F and can then engage its flight muscles even when it’s 32 degrees F outside!) The overwintering queen arctic bumblebee (who is able to survive brutally cold sub-zero temperatures throughout the long arctic winter) uses this same metabolic-muscle engine to stimulate ovulation so that the retained sperm (from her pre-hibernational mating back in the fall) can fertilize her ova. Further, the arctic bumblebee is larger than our temperate bumblebee so it has a reduced surface area to volume ratio that helps to slow down heat loss. It is also covered with a thick coat of highly insulating hair. The dark color of the arctic bumblebee also helps it absorb heat from the, admittedly weak, arctic sun.

So why did this group of six scientists drive a thousand miles through Alaska to search for this arctic bumblebee? Think about global warming changing the climate and then the flora and fauna in lower latitudes. One hypothesis is that mobile species (like bumblebees) will move north as the climates of their traditional ranges get warmer. But, if this happens, where will the bees at the very edge of northern world go? What will happen to all of the wild plants that specifically rely on them for pollination? These were the big questions these bee hunters were asking.

Photo by Trounce, Wikimedia Commons

Photo by Trounce, Wikimedia Commons

In another bee paper published this past summer in Plos Pathogen (August 11, 2016) , scientists from Cambridge University found that tomato plants infected with the cucumber mosaic plant virus attracted more bumblebees (their primary pollinator) than non-infected plants. The consequence of this increased pollinator attention was that the infected tomato plants even though they were energy stressed by their viral loads produced just as many fruits and seeds as uninfected plants. The virus made the tomato plant “more visible” to the pollinating bumblebee! Possibly the positive, reproductive impacts of this viral infection will eventually out-weigh its negative, physiological effects on the plant! This infection response may be the first step in a co-evolutionary symbiosis between the virus and the tomato!

In another bee paper (published in the July 27, 201 Proceedings of the Royal Society B) scientists in New Zealand found that honeybees exposed to neonicotinoid pesticides had less viable and less active sperm than unexposed honeybees.  Previous studies have shown that both honeybees and bumblebees are strongly attracted to plant nectars that contain neonicotinoid pesticides so this impact could be quite significant. Neonicotinoid pesticides are used for insect control on many type of crops but have been linked to significant bee damage in many studies (The European Union, in fact, has recently banned these chemicals because of their links to high levels of bee mortality. Bills have been proposed in the US Congress to restrict the use several of these pesticides, but these bills were sent to committee and no definitive action was taken). Possibly this inhibition of reproductive efficiency is one of the mechanisms by which so much bee damage is mediated. In a related study published in Nature Communications (August 16, 2016) the use of these neonicotinoid pesticides on oilseed rape fields in England over an 18 year time period had significantly negative impacts on 62 species of wild bees.

Photo by H. Zell, Wikimedia Commons

Photo by H. Zell, Wikimedia Commons

And, finally, in a paper just published in Current Biology (October 6, 2016): a South African flower (Ceropagia sandersonii) was found to synthesize a mixture of scent molecules that mimicked the alarm and distress pheromones produced by a wounded honeybee (Apis mellifera). These scent molecules attracted predatory Desmometopa flies to the flowers (these flies feed avidly on honeybees that have been captured or wounded by spiders (or other predators) in these flowers). These flies are also the primary pollinators of C. sandersonii! So, by ringing an olfactory dinner bell for the flies, the flower gets more focused and more frequent pollinator visits and a much more efficient overall rate of pollination!

So bees are being pushed to the edge of the world. They are also participating in ongoing co-evolutionary transformations, are being sterilized by pesticides, and are indirect participants in elegant chemical ecological systems. No wonder we keep talking about them!

 

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Signs of Fall 8: Interacting With Birds

Photo by D. Sillman

Photo by D. Sillman

Last winter I wrote about Helen MacDonald (the author of H is for Hawk) and her N.Y. Times article entitled “Why do we feed wild animals?” The primary motivation, according to MacDonald, that leads us each year to spend three billion dollars a year on wild bird feed alone, is to feel like we are part of the natural world! As MacDonald wrote so eloquently, feeding wild animals “surrounds us with creatures that know us, are able to forge bonds with us, have come to regard us as part of their world.”

Now there are good consequences and bad consequences when the animals have humans as their worldly companions. With expanding food sources latitudinal ranges can be expanded (as we noted for North American cardinals (Cardinalis cardinalis) and goldfinches (Spinus tristis)), migration routes (and all of the stresses and dangers associated with migration) can be shortened (as we noted for the Eurasian blackcap (Sylvia atricapilla), and spring breeding health and nestling vigor and survival can be improved (as we noted for populations of Wisconsin, black-capped chickadees (Poecile atricapillus)). We also have seen, though, that diseases can be more easily spread between birds feeding in densely utilized, human-made feeding stations (as in the case of house finches (Haemorhous mexicanus) and the epidemic spread of mycoplasmal conjunctivitis), and the reproductive successes of feeder fed vs. naturally fed birds (as in a study in England on the blue tit (Cyanistes caeruleus) and the great tit (Parus major) (two European relatives of the chickadee)) can be quite different if the provided bird seed is poor in nutritional quality (high fat, low protein with low levels of essential nutrients). Feeder fed birds in this study laid fewer eggs, had fewer fledges and had a significantly reduced overall level of reproductive success.

Photo by T. Bresson, Wikimedia Commons

Photo by T. Bresson, Wikimedia Commons

Last spring a paper was published in the journal Movement Ecology by scientists from the University of East Anglia and the University of Lisbon that looked at the influence of open landfills in Portugal on the yearly migration patterns of white storks (Ciconia ciconia). Using GPS/GSM trackers that they attached to a cohort of storks (not an easy task, I am sure!) they confirmed observations that had been made at a number of these Portuguese landfills that the storks were increasingly bypassing their long, winter migration to sub-Saharan Africa and were remaining in Portugal through the winter to gorge on garbage in the landfills. The storks were also observed to eat many forms of non-food trash including paper and computer parts and often got their long beaks entangled in the rotting debris.

It would be interesting to study the influences of this low quality and possibly toxic diet on the life expectancy and reproductive outcomes of the storks. Fortunately, though, a long-term study of this system will not be possible since the European Union has mandated the closure of the Portuguese landfills by 2018 (they will be replaced by composting factories). How the garbage adapted storks will react to the sudden loss of their food supply is another good topic for a study!

Photo by G.G. Ioham-Braun, Wikimedia Commons

Photo by G.G. Ioham-Braun, Wikimedia Commons

On a less disgusting note, a paper was published this summer in Science (July 22, 2016) in which the communication biology between humans (members of the Yao people of Mozambique) and the greater honeyguide bird (Indicator indicator) was examined. The Yao regularly search for honey in the forests around their villages and often recruit a honeyguide bird (an African cuckoo species) to assist them in finding the honey-rich bee nests. Birds that participate in successful hunts are rewarded with a piece of honeycomb (a highly desirable food item for the bird!). The Yao use particular vocalizations (especially a “brrr-hum” sound) to attract and maintain contact with their honeyguides. Scientists from the University of Cambridge and several institutions of South Africa wanted to determine if the vocalizations used by the Yao were specific to attracting the honeyguides, or if more generalized sounds directed at a passing bird would also elicit the mutualistic hunting behavior.

Using high quality recordings in the field, these scientists clearly showed that the specific “brr-hum” call was interpreted by the honeyguides as a call to join humans in a hunt for bee’s nests. The honeyguides do feed on bee’s wax on their own, but approaching a bee nest can be quite a dangerous task for them. Multiple bee stings can actually kill an adult honeyguide. So, the mobilization of humans with their technologies (axes, saws, and smoke) greatly reduces the probability of injury and greatly increases the likely of a good meal of bee’s wax at the end of the day!

Anthropologists classify this vocalization specialization between humans and honeyguides as a true and possibly quite recent co-evolutionary event. The Yao, of course, learn this relationship as a generationally conveyed component of their complex culture. It would be interesting to see if the honeyguides also learn their roles in the hunt as a cultural trait passed down from parents to offspring, or if there is a more hardwired, genetic component to their behavior.

Photo by U.S. Geological Survey, Public Domain

Photo by U.S. Geological Survey, Public Domain

And finally, a very disturbing study also published this summer in journal mBio (July 26, 2016) examined a phenomenon in Alaskan black-capped chickadees that had been observed since the 1990’s: overgrown, warped beaks that cause an affected bird to be unable to groom or eat. This condition turns out to be caused by a new picornavirus called “poecivirus” (after the black-capped chickadees’ scientific name, Poecile atricapillus). This disease is a type of “avian keratin disorder,” and it causes the top and bottom of the beak to grow out in opposite, curving directions.

The virus directly affects the fibrous protein layer around the bone and disrupts the normal growth and repair homeostasis of the beak. Avian keratin diseases (which are caused by several other types of viruses) are found in twenty-four bird species in North America and thirty-six species in the United Kingdom. It is not clear how easily transmitted this new virus is and whether it represents another potential threat to birds feeding in high densities at human stocked bird feeders.

So, to be safe let’s all try to remember to keep our bird feeders clean and well stocked with high quality seed! Also, let’s all work hard to keep our individual contributions to our local landfills as minimal as possible! We don’t want our great blue herons or any other birds to take up the garbage-feeding behaviors of the Portuguese white storks. And, finally, we may not have honeyguides in Western Pennsylvania to lead us to caches of wild honey, but we do have a wide range of more subtle mutualistic symbioses to enjoy. We just have to open our eyes to find them!

 

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Signs of Fall 7: The Anthropocene “R” Us!

Photo by R. Pederson, Free Stock Photos

Photo by R. Pederson, Free Stock Photos

Last week I came across an article in the New York Times that described a species with which I am very familiar. It is a species that lived in my home for over a decade entertaining both my children and my cats. It is a species for whom many friends of mine devote a great deal of time, resources and energy to keep in luxurious captivity.  The article, though, looked at this remarkably innocuous animal, an animal that is the poster species for a calm, quiet, peaceful existence, from an extremely unexpected point of view.  The article described goldfish (Carassius auratus) as quite possibly the most dangerous and destructive exotic, invasive species affecting our aquatic ecosystems today!

Goldfish?  Really? I might have expected that Burmese pythons, or walking catfish, or sea lampreys, or zebra mussels, or even sewer-reared crocodiles would take on the mantle of “worst exotic aquatic species.”  After reading the article, though, I can understand the case being made against the goldfish!

I have frequently written about invasive species in this blog. Looking back over the posts published in just the past year I found many exotic, invasive plants (like multiflora rose, Japanese knotweed, Amur honeysuckle, garlic mustard, and tree-of-heaven) mentioned in the context of hikes and explorations of my yard and field. I also found several exotic invasive birds (English sparrows, European starlings) in my discussions of my bird feeder and surrounding nesting communities. There were also exotic invasive insects both invading my house and garden (pavement ants and brown marmorated stink bugs) and also threatening the trees in my woodlot and in the surrounding forests (emerald ash borers, wooly adelgids, and Asian long horned beetles). There are also exotic, invasive insects lurking in the margins of our ecosystems (like the Asian tiger mosquito) that may act as vectors for serious human diseases!

Photo by D. Sillman

Photo by D. Sillman

I have described house cats as exotic invasive species (their ability to destroy populations of birds and small mammals is almost human in its pace and completeness!), and have even reported that some ecologists look at the wide array of introduced European earthworms (including the very familiar “nightcrawler”) as remarkably destructive exotic species that have decimated the leaf litter habitats of a wide range of invertebrate species. A few years back, I also wrote about the invasive consequences of introduced eucalyptus trees in Peru. The eucalyptus’ allelopathic root and leaflet chemicals poison the soil they grow in for many decades even after the trees have been cut and removed!

Humans have sculpted entire biomes out of invasive species! It is the world in which we live!

But, back to goldfish.

My own experience with goldfish started in the early 1990’s. I bought a ten gallon aquarium for my children and then took them to the pet store to let them pick out two goldfish each. At the pet store neither child noticed that the tank from which they were going to make their selections was labeled “feeder fish.”  These fish had a very short expected life span and were destined to be given to larger, carnivorous fish as meals and snacks. The four fish they picked out were very distinctively colored and patterned so it was easy to tell them apart.  They were named according to a popular cartoon video of the time (“The Land Before Time”) so, without any sense of irony at all we had goldfish named  “Little Foot,” “Big Foot,” “Sara” (which was actually “Cera” from the triceratops in the cartoon), and, in a return to goldfish standard names, “Goldie.” Big Foot, because of her great appetite and rapid growth rate eventually came to be called “The Hog.”

The four fish were wonderful. All four grew into substantially sized individuals (Hog, of course, was the largest). They all would have grown even larger if I had put them in a larger aquarium (and this is a characteristic of the species that we will come back to in a few minutes!). Watching the fish tank was almost as good as watching television (our cats actually seemed to prefer the tank to any of the TV shows or video cartoons regularly shown in our living room).

Little Foot, Hog, Sara, and Goldie lived for just over ten years, and many people have expressed surprise that goldfish were able to live that long (cleaning the tank every week helped to keep their environment free of toxins and pathogens. The tank cleaning was my job, of course). Ten years, though, is not really an unexpected time frame for goldfish. They can live for up to twenty years in the wild or up to thirty years in captivity. The way we have been exposed to goldfish, though, has not stressed their amazingly long potential life spans. Instead, starting with U.S. government (Commission on Fisheries) programs that gave away goldfish to Washington D.C. residents back in the late 1800’s (over 20,000 free fish a year!) up to every carnival or fair that had glass bowls and plastic bags of goldfish for game prizes or giveaways, goldfish have been presented to the public as a disposable ornamentation, and this brings us back to discuss some of their characteristics that make them such a dangerous exotic invasive species.

Public Domain

Public Domain

As we mentioned before goldfish will grow to a size that fits the environment in which they live. In a small aquarium, the fish will stay small. In a larger aquarium, the fish will get larger. If a goldfish, though, lives in a pond or a river, they can really exert their growth potentials almost without limits! Four pound goldfish, sixteen inches long are regularly found in the wild! And, with humans thinking of goldfish as disposable knick-knacks, many of them have ended up in previously wild ponds and streams!

The behavior of the feral goldfish in their habitats is also quite destructive. They swim just above the soft bottoms of their rivers and lakes and uproot aquatic plants and roil up sediments causing the water to become turbid and throwing its nutrient composition out of balance. Out of control algae growth often follows (further spurred on by the nitrogen rich excretions of the goldfish themselves). The goldfish also eat everything (especially small invertebrates and fish eggs) and destroy established food chains and reproductive cycles. They can also transmit a number of exotic parasites and diseases which can decimate the other fish in their streams and ponds.

Female goldfish can produce up to forty thousand eggs a year! Goldfish can also interbreed with many species of wild carp and generate an invigorated array of hybrid species. With an absence of effective, natural predators a large percentage of the young goldfish survive to breeding age setting up an explosive cycle of exponential growth.

Photo by bjwebb, Wikimedia Commons

Photo by bjwebb, Wikimedia Commons

Goldfish are also very active swimmers. A single individual can regularly swim many hundreds of yards up and down a river each and every day. One monitored, feral goldfish swam over 140 miles along a river during an observation year! Goldfish are also able, possibly instinctively, to find suitable spawning habitats in which their offspring have very high probabilities of success and survival.

The other characteristic of goldfish that add to their potential to be an extremely destructive, invasive species is their intelligence. They can be trained to do complex tasks and even to recognize and respond to different pieces of music! The Times article mentioned an engineer from Pittsburgh who trained his goldfish to push soccer balls into nets. While the abilities to play soccer and to tell Mozart from Beethoven are not direct survival aids in the wild, the high cognitive skills displayed by this species make it an efficient problem solver and rapid learner and a formidable adapter to almost any ecological milieu.

So, as we consider the world and our geological era as re-made by humans, that “Anthropocene” all around us, let us not forget out dear friend (and mortal, ecological enemy?) the goldfish!

 

 

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Signs of Fall 6: Some Fall Plants

(Some of the “science” parts of this blog were also used in a post published in September 2015)

Photo by D. Sillman

Photo by D. Sillman

On my drive to work I go past many “abandoned” fields. This time of year, though, these fields are stunningly beautiful in their array of autumnal colors and textures. Golden rod is the dominant plant (or dominant group of plants!) in most of these old fields, but it is well framed by clouds of the flowers of white snake root, and the orange and yellow flowers of jewelweed. Most fields also have the tall, deep purple flowered stalks of Joe Pye weed and iron weed punctuating all of the greens and golds. Finally, to finish off the very “Impressionistic” canvas of these old fields, there are also the scattered pink flowers of Pennsylvania smart weed usually visible on the edges of mass of plants. If you have the time to stop and take a closer look at the vegetation, you see dozens and dozens more species filling in all of available spaces! The closer you look, the more you see!

The fields look soft and inviting with all of these wonderful “weeds!” Often on the road-side or drainage ditch-side of the fields stands of Japanese knotweed (Fallopia japonica) grow in dense, monocultural, palisades that literally shade and choke out all of the other plant species under and around them. Knotweed is an exotic invasive that has taken over many thousands of acres of formerly diverse native vegetation.

All of these flowers, though, both native and invasive, are covered with pollinators (especially honey bees!). The fall honey that they will make will be dark and full of flavor and, speaking for myself anyway, is just the thing to help us survive the coming long, cold winter!

Photo by D. Sillman

Photo by D. Sillman

Golden rod is called “summer’s end” in England. Its appearance announces the fading summer and starts the ecological countdown to frost and, eventually, winter. There are twenty native species of goldenrod (genus Solidago) in Pennsylvania and another hundred plus species around the world. Solidago species have an amazing ability to crossbreed with each other and, so, close examination of any goldenrod patch is sure to reveal a wide range of types of individuals.

Goldenrod’s coincident flowering with the onset of the “hay fever” season has led some to assume that its pollen causes this late summer malady. Goldenrod pollen grains, though, are very large and sticky and are dispersed not in the wind but, rather, on the bodies of pollinating insects like bumble bees, honey bees and soldier beetles. The absence of wind dispersal makes this pollen a very unlikely contributor to “hay fever” allergies. “Hay fever” is mostly an allergic reaction to ragweed (Ambrosia spp.) and its great, airborne clouds of allergenic pollen. Scattered among the goldenrod are numerous, very unassumingly flowering, ragweed plants.

Photo by D. Sillman

Photo by D. Sillman

There are two recognizable species of jewelweed in our area fields. Both have the same small, very distinctive, trumpet-shaped flower, but one species grows quite tall and has yellow flowers (probably Impatiens pallida or the “pale jewelweed”) while the other species is shorter and has orange flowers  (probably Impatiens capensis or the “spotted jewelweed”). Dense mixed stands of both species border the open fields and often extend back into the shady areas of surrounding woods.

Jewelweed is widely thought to be a natural remedy and preventative agent against the delayed hypersensitivity reaction triggered by skin contact with the oils of the poison ivy plant (there is a lot of poison ivy, too, mixed in with the golden rod of the field and the jewelweed of the field edges!). There have been a number of controlled studies looking into the influences of the leaves and fluids of jewelweed on skin rashes, but none of them have clearly demonstrated any effective anti-inflammatory or even any anti-pruritic (anti-itch) impacts. There is some suggestion, though, that chemicals in the jewelweed fluids may very subtly alter the chemical structure of the poison ivy oils and, possibly, make them slightly less effective as a trigger for their delayed hypersensitivity reaction.

Photo by D. Sillman

Photo by D. Sillman

White snake root (Ageratina altissma) is a member of the traditional Eupatorium botanical group (as is Joe Pye weed (Eutrochium spp.)). This has been an incredible year for white snake root! I have never seen it growing so thickly along all of the sunny edges of my field at home and around the fields I pass on my way to work.  These plants with their clusters of bright white flower heads seem to shimmer and glow even in pale, morning or evening sunshine!  White snake root, though, like all of the Eupatoria, is very poisonous to animals. Its poisons can be transferred to the milk of a cow (or any other lactating mammal that might ingest the plant) and can cause “milk sickness” syndrome. Milk sickness is a very serious and potentially fatal condition. Extirpation of this plant from areas inhabited by grazing animals is extremely important. Animals are especially likely to consume white snake root during drought years as failing pastures force them to forage on less and less palatable plants. A historical note:  Abraham Lincoln’s mother, Nancy Hanks, died of milk sickness when Lincoln was nine years old.

Photo by J. Grandmont, Wikimedia Commons

Photo by J. Grandmont, Wikimedia Commons

Witch hazel (Hamamelis virginiana) is another notable plant of autumn, although we have to walk out into the woods in order to see it. Witch hazel is a large shrub (or small tree … the debate about this classification rages on!) found extensively throughout Western Pennsylvania. A witch hazel shrub (I fall into the “shrub” side of botanical argument!) has numerous basal branches that are six to eight inches in diameter that spread out laterally into an arching,

Witch hazel flowers Photo by D. Sillman

Witch hazel flowers Photo by D. Sillman

dome-like shape. It can grow twenty to thirty feet tall (OK, a thirty foot tall, woody plant sure sounds like a “tree” to me!). Witch hazel shrub/trees flower in the autumn, long after the flowering season has passed for most trees (or shrubs). Its flowers are bright yellow and complete and, so, are potentially self-pollinating. Pollination is usually accomplished, however, by a wide variety of insects. Although pollination occurs in the autumn, fertilization of the ova does not occur until the next May. The developing fruit, then, coincides with the timing of fruit formation seen in most of the other fruit producing plants of the ecosystem. Humans in many cultures utilize witch hazel for a variety of medicinal purposes. The bark and leaves are used to make topical medications for the treatment of cuts, abrasions, hemorrhoids, eczema and other skin conditions. Native Americans also brewed a medicinal tea with its leaves.

Witch hazel has been described as a “docile” plant within its natural communities (sort of the opposite of the invasive knotweed!). Its slow rate of growth and spread make it an unlikely ecosystem invader and often restricts it to stable, long-undisturbed forest sites. Out on the Penn State New Kensington Nature Trail, we have a beautiful witch hazel thicket on the far side of the stream that has not appeared to change over the thirty years I have been monitoring it! Slow growth, slow reproduction and its steady equilibrium within its habitats are the hallmarks of this interesting shrub/tree! It is worth the long walk down the Nature Trail to the ravine and the stream to see its yellow, fall flowers.

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Signs of Fall 5: Updates on Amphibians

H. crucifer Photo by USGS (Public Domain)

H. crucifer Photo by USGS (Public Domain)

Back in April I wrote about my spring observations on our local amphibians. Neither spring peepers (Hyla crucifer) nor wood frogs (Rana sylvatica) were very abundant in Western Pennsylvania this year. Low winter snow fall totals (thanks, El Nino!) led to a very small spring snow melt. When these low melt volumes were coupled with a much lighter than average spring rainfall, the wetlands and vernal pools on which these frogs rely for reproduction became both very reduced in size and also fleetingly transient. Gray tree frogs (Hyla versicolor), though, were out in force at night trilling both in the spring and on through the summer. These tree frogs may be somewhat less picky than peepers or wood frogs in choosing their breeding ponds, and, so, may have been less impacted by the low volume of the seasonal pools.

Photo by D. Sillman

Photo by D. Sillman

Out at Todd Nature Reserve pond, both bull frogs (Lithobates catesbeianus or Rana catesbeiana)  and green frogs (Lithobates clamitans or Rana clamitans ) were very abundant and active this year. Their populations seemed unchanged from previous years. The water level of the Todd pond was high in spite of the dry winter and spring, and these frogs showed little sign of environmental stress.

A sixth amphibian that made a late appearance in our field was the American

Photo by Scrumshus, Wikimedia Commons

Photo by Scrumshus, Wikimedia Commons

toad (Anaxyrus americanus, formerly  Bufo americanus). For years, large “bufo” individuals have inhabited our garden and flower beds turning up unexpectedly when we were pulling weeds or digging potatoes. When Deborah and I taught “Kids in College” summer classes at Penn State we could count on going out the night before the class sessions started and turning up a large, mature American toad usually lurking in our front flower bed. The kids really loved watching these toads eat insects in the lab and they were wonderful living foci for so many interesting biological and natural history discussions! American toads can live for up to thirty years, so I like to think that all of our Kids in College years might just have featured a single, very gregarious individual who regularly summered in our front flower bed!

Anyway, early in August an army of small, immature American toads showed up in Izzy’s side yard! They were just a bit smaller than the end of my thumb, and they hopped about furiously (and randomly) whenever Izzy put her nose to the squirming grass! The adult toads must have found the slow, shallow stream down at the bottom of the field (and each other!) and created a bumper crop of tadpoles which developed into little toads. The tiny toadlets are now spreading out from their freshwater nursery and were gobbling up any insects that stumbled into their paths. A very small percentage of them will survive to late fall when they will dig down into the leaf litter and soil to hibernate their way through the winter. They will reach reproductive maturity after two or three years of wandering, eating, and digging and will then find their mating puddle or pond and start the cycle all over again. These truly wonderful toads just need some cover (woods or gardens), insects and other invertebrates to eat and a reliable source of clean water for mating.

Last year we went on a salamander hunt in Harrison Hills Park, but we didn’t find any in spite of the abundance of perfect, amphibian habitats throughout the park. This year was so warm and dry that we didn’t even go out and look.

Photo by D. Sillman

Photo by D. Sillman

I have occasionally seen salamanders in the persistently wet drain at the bottom of my driveway, but this year due to re-construction of the driveway retaining wall and also our very dry April through July, I saw no salamanders at all until the first day of October! Deborah and I were out moving a few of the rocks we had placed on the landscaping cloth to hold it and its covering pine mulch in place. We lifted up a rock to re-position it when this fellow pictured above wiggled out into view. He was as fine a northern slimy salamander (Plethodon glutinosus) as you could ever expect to see! After he posed for a few pictures he dove back under some of the undisturbed rocks. I hope that he sleeps well this winter and finds a mate so that they can fill up my driveway drain with eggs!

This past May the results of a major U. S. Geological Survey study on global amphibian populations was published in the journal Science Reports. David Miller a Penn State assistant professor of wildlife biology and Staci Amburgy, a Penn State doctoral candidate in ecology were both important participants in this study. Their findings include a very precise estimate of the rate of the world-wide decline in amphibians (populations are shrinking at a rate of 3.79% per year!), and an analysis of the causes of this observed decline (chytrid fungal infections, urbanization and agriculture (causing habitat loss), pesticide pollution, and climate change). The report also noted that the rates of amphibian decline are different in different parts of the world, and that the relative significance of the causal agents of these declines are also different in different places. In the United States, for example, amphibian numbers are declining most rapidly in the Rocky Mountains (primarily due to the effects of pesticides) and on the West Coast(primarily due to the effects of climate change).

There are 7000 known (living) species of amphibians. They have existed on Earth for three hundred million years. They were the first truly terrestrial vertebrates! In the last twenty years, 168 amphibian species have gone extinct and 2469 species have declining population numbers (of these declining species 1856 are under the threat of extinction). In North America there are 440 amphibian species, and 41 of these have either gone extinct or are critically endangered and another 107 are threatened by or vulnerable to extinction.

If we look at the amphibians here in Western Pennsylvania we see in miniature the problems facing amphibian species around the world. Our salamanders have succumbed to the stresses of habitat destruction and, possibly, acid rain. Our spring peepers and wood frogs have declined because of habitat destruction (especially the human generated landscape erasure of their vital vernal pools). Our great generalists (the American toads) and large pond dwellers (bullfrogs and green frogs) are hanging in there, but I am sure are in some decline because of habitat degradation and water pollution.

The Spring sounds empty without the choruses of the peepers, and woods seem less alive without the thrashing and “quacking” of the wood frogs. Everyone needs to do more to help these species survive!

 

 

 

 

 

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