Signs of Spring 2: Daylight Savings Time

Sunrise over the Mojave Desert. Photo by J. Eastland. Wikimedia Commons

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Last weekend we changed over to Daylight Savings Time (DST). The “spring ahead” change in our clocks does nothing to alter the total amount of daylight we get in a day, but it does change our perceptions of lengths of day and night. Supposedly, we quickly compensate for our lost hour of sleep on that first Sunday morning after the time change, but many of us, I am sure, spend that day and the next night (and maybe a few more days and nights after that) feeling edgy and groggy. Most of us will return to “normal” in a few days, although I did have a roommate at college who took weeks to recover from either the spring or fall time changes.

All sorts of studies have explored the impacts of the fall and spring time changes The fall, with its promise of an extra hour of sleep, seems more benign than the spring change which takes that hour away. One researcher referred to both changes, though, as a type of “jet lag.” Sleep pattern disruptions, headaches, and mood changes were the dominant symptoms, and like jet lag the symptoms fade within a few days.

The spring change, though, has some potentially serious consequences: for several days after the “spring ahead” clock change there are increases in work-related injuries, and, possibly (although there are conflicting data on this) an increase in morning traffic accidents. Interestingly, according to a 2012 study published in the Journal of Applied Psychology, for several days after the spring time change office workers also increased their on-the-job “cyberloafing” Internet time. Maybe web surfing is an adaptive way to avoid accidents and injuries!

Mornings are suddenly darker than they were. We have been on a steady march to more and more sunlit hours and minutes ever since the sunlight minimum (nine hours and sixteen minutes and fifty-six seconds) of the winter solstice last December 21. Today (March 14) there will be eleven hours and 51 minutes and 56 seconds of sunlight, and thanks to DST most of those added 155 minutes of sunlight will be visible in the late afternoon and early evening. My neighbor is very excited to have later sunsets. She regularly sleeps through most of the morning hours, and the time change makes the waking part of her day much more sunny and useful! It is, however, no fun to walk a dog in the cold morning by flashlight. We are all pleased, though, to be moving toward the Summer Solstice on June 21! We will have 15 hours and 3 minutes of sunlight that day. That will be plenty to go around for both sunlit mornings and evenings.

Silver maple in flower. Photo by D. Sillman

Anyway, our shift to DST does not affect organisms other than humans, but the on-going increase in the ratio of light to dark minutes during a day  does affect almost every plant and animal species around us. The flower buds on the silver maples and the red maples are swelling and will burst open possibly in just another week. The male bluebirds are getting cranky with each other and are partitioning off the territory they had willingly shared through the winter. Migrating males are also arriving making the territory partitioning even more intense. Our summer migrants (the tanagers, grosbeaks, buntings and orioles) have felt the daylight changes, too, and are starting to gather themselves for their long flights north!

Where did DST come from?

Painting by J. Duplessis. Wikimedia Commons

Most histories on the subject start with Benjamin Franklin and his letters to the French authorities in Paris describing the inefficiency of unused daylight in the early morning and the “candle cost” of the early darkness in the late afternoon and early evening. Shifting clocks ahead by an hour, he contended, would more appropriately align the available daylight hours to the activities (and candle usages) of the citizens of Paris.

In World War I Germany shifted its national clocks to extend the daylight period into the evening in an attempt to save energy, and quickly other nations of the world on both sides of the conflict did the same. Retailers in large cities noticed that more people were out walking (and shopping!) on the days with extended afternoon sunlight and lobbied to keep DST after the war. Similar energy arguments were made in World War II and the seasonal return to DST became institutionalized in many national cultures. In fact, the most cogent argument in favor of DST is that it stimulates the consumer economy. Farming interests were quite opposed to the shift to DST and the attempts to portray it as a benefit to farmers are tortuous in their logic and foundations.

In the United States the passage of the Uniform Time Act of 1966 required states to conform to their respective Standard Time zones but allowed them some flexibility with regard to DST. Only Arizona, Hawaii and Puerto Rico, however, have opted not to “spring ahead” into DST each March. There are also several states that have made attempts to make DST a permanent, year-round clock setting although the Uniform Time Act does not allow states the freedom to make these type of changes. It is argued by the permanent DST advocates, though, that shifting daylight minutes and hours into the more highly used afternoon and evening time periods is a better use of sunlight resources. As one DST researcher put it “everyone loves DST!”

Does DST save energy?

Photo by Pixabay

The simple answer is “yes and no.” Less energy is used for artificial lighting (Ben Franklin was right about the potential “candle” savings!), but more energy is used for almost everything else! People waking up in the cold, dark early morning hours use considerable amounts of energy for heating. People taking advantage of the extra daylight in the afternoon and evenings are most likely to drive somewhere (a park or a mall or a shopping district) to enjoy the extra sunlight (and gasoline usage does increase when DST is introduced). Also, air conditioning usage goes up in the warmer afternoons and evenings. A 2006 study in Indiana found that electricity usage increased by 1% when DST was  introduced (estimated cost: $9 million!).

As I said at the beginning of this essay, the shift to DST affects humans but not the plants and animals around us (except for our poor dogs, of course, who now have to do their morning walks in the dark). This fact, though, is not always clear to people who, understandably, have a difficult time grasping just how the idea of “an hour more daylight” is actualized. Concerns have been raised that this extra hour will cause lawns and crops to wither and die, and that it will so disrupt the feeding and activity schedules of farm animals that milk production, egg laying and meat production will suffer. Possibly even wild birds will begin to migrate or nest at inappropriate times just because of this “unnatural” disruption of our clocks.

Anyway, most of us will stop noticing the time change in a day or two. I also guarantee you that the birds out in our yards and fields and the other animals out in our woods never noticed any of these changes to begin with!

 

 

 

 

 

 

 

 

 

 

 

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Signs of Spring 1: Monarchs!

Photo by D. Sillman

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As I reported last summer (Signs of Summer 8, July 25, 2018) monarch butterfly numbers and their reproductive efforts here in Western Pennsylvania looked good.  The fields at Harrison Hills Park, for example, were loaded with butterfly weed and milkweed and also a great diversity of flowering plants that serve as nectar sources not only for monarchs but also for many other important insects and birds. In July Deborah and I spotted several large (possibly 5th instar) monarch caterpillars on these milkweed plants. Also, a friend down in New Kensington reported monarch eggs on her milkweed, and some other friends who live along the Allegheny River near Freeport reported abundant monarch eggs and caterpillars on their milkweed! Monarchs were also frequently seen flying through Lower Burrell, Upper Burrell, Vandergrift and Apollo all through the late summer and early fall.

We speculated that the warm weather last spring in Texas might have given the migrating monarchs a boost (March 2018 in Texas was 5.3 degrees F warmer than average!). It might even have kept them from flying into the unseasonably cold March weather in the eastern United States. When the migrating monarchs from Mexico stayed in Texas longer than usual they responded with a population boom! Although limited by the available milkweed, the Texas monarchs multiplied and then, as the weather in April began to moderate, surged out across the eastern  and midwestern United States.

Female Monarch (photo by K.D.Harrelson (Wikimedia Commons))

On-line monarch migration maps showed the steadily expanding line of migration of the butterflies: In March they had reached a line between Texas and Florida, by April they had traveled north to a line roughly between Oklahoma and South Carolina, and by May they were up to a line between Kansas and Maryland. By early June they had reached a line between Iowa and Ohio, and by late June had finally gotten to Pennsylvania, New York and New England.

The monarchs reproduce all along their migration route (so milkweed is critical at each step!). At each milkweed stop females, after mating, lay three to four hundred eggs on the milkweed (spreading their eggs out over a large number of plants). Then the adult monarchs die. The eggs hatch in three to five days depending on the temperature, and the emerging larvae (the “caterpillars”) feed first on the egg capsule and then begin to eat the milkweed leaves. They molt five times during their larval life stage and increase their body mass more than two thousand times. The caterpillars take between 9 and 14 days to go through their five growth phases.

Monarch caterpillar. Photo by D. Sillman

By late July, migrating adults and caterpillars in many stages of coming and going were all over Western Pennsylvania. Pennsylvania is just one of stops on this seasonal northward surge and eventual southward retreat of monarchs. Some of the adult monarchs that hatch here in mid-summer might, in a typical year, continue on north to lay more eggs on the later growing milkweed in New York and New England. Other monarchs that mature here in late summer, though, will turn around and begin the long journey back south. These late summer/early fall born monarchs are part of the overwintering cohort that tries to find its way to the coniferous forests in the mountains of the Mexican states of Michoacán and Mexico. These overwintering monarchs live 8 or 9 months (compared to 2 to 5 week life span of the “summer” monarchs) and will be the individuals that push back north into Texas next February and March where they will mate and lay eggs and start the migration cycle all over again!

This past fall reports from all over the eastern and midwestern United States matched what we had observed here in Western Pennsylvania. Numerous migration roosts (resting gatherings of migrating monarchs) were reported in New York, Ohio, Michigan and all across the upper Midwest. Many of these roosts contained more than a thousand individual butterflies!  There were more monarchs migrating south this past year than had been seen in many years! Also, the Fall 2018 weather here in the East was quite mild. Summer-like conditions hung on well into the fall and may have given the migrating monarchs another boost!

Photo by T. Hall, Flickr

One of the most accurate ways to access the monarch butterfly population is to count them when they are in their overwintering forests in Mexico or, even easier, to measure the area of the forests that they occupy. The most recent overwintering data has just been released. For the 2018/2019 season 6.05 hectares (16.3 acres) of forest were filled with overwintering monarchs! This is represents a 144% increase over last year’s occupied forest area and is the largest forest area occupied by monarchs since 2006/2007!

 

The Eastern monarchs, then, finally had a good year!

There is also a western population of monarchs that is separated from the eastern monarchs by the Rocky Mountains. These western monarchs overwinter in the coastal forests of California rather that the mountain forests of Mexico. The Xerces Society for Invertebrate Conservation conducts a yearly census of these western monarchs. Their findings this year are very disturbing. They counted only 28,000 overwintering monarch butterflies in their study sites. This represents an 86% decline from the 2017/2018 count and a 99.4% decline from the 4.5 million monarchs that overwintered on the California coast back in the 1980’s.

This decline in monarchs is attributable to many factors. There has been a precipitous drop in the total area of milkweed patches throughout the west primarily due to herbicide use and urban development. Also, the continuing hot weather and drought, thought to be directly attributable to climate change, has led to extensive wildfires that have destroyed vast areas of forest and wild plants needed by the monarchs for roosting, cover and nectar. Under the stress of all of these pressures, the western population of monarchs could, according to some experts, be extinct in less than twenty years!

So many people around the country are trying to pitch in to save the monarch! Monarchs, though, all across our country, are still gravely threatened by habitat loss, pesticide and herbicide use, and climate change. Plant some milkweed! Plant native plants (for nectar fueling sites!)! Use fewer herbicides and pesticides! All of Nature will benefit from these steps, and we will continue to help to bring the monarchs back!

 

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Signs of Winter 14: More on White-tailed Deer!

Photo by Pixabay

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White-tailed deer form large herds in the winter. These herds are made up of several family units that had been relatively independent of each other throughout the spring, summer and fall months of food abundance. It may seem paradoxical that when food resources become limited the deer bunch up into large groups, but by confining themselves to the most sheltered and protected sub-sections of their broader summer ranges they reduce some of the stress of the cold season and also gain some security from predators. The entire herd may also gain some benefit from the leadership and knowledge of the older does (which I will talk about below).

Mostly, deer rely on their fat deposits for their metabolic energy in the winter. At the start of the winter a deer in prime condition may have as much as 30% of its body weight in fat! The fat is subcutaneous (which also adds to body insulation) and is also found extensively around the internal organs of their bodies. This is their “fuel tank” carefully filled through the spring, summer, and fall. In normal years these fat deposits represent enough calories to carry the individuals through to the next, bountiful spring.

Deer, though, also consume low caloric browse throughout the winter. Preferred winter browse include cedar (like the arbor vitae on the east side of my property!), sassafras, apple, most types of maples, basswood, and flowering dogwood. Secondary browse includes hemlock, honeysuckle, mountain ash, willow, white oak, and many other deciduous trees. Last resort choices for browse (sometimes referred to as “starvation food” because if you see these trees being browsed by deer you know that the herd is in trouble!) include pines, mountain laurel, beech, aspens, poplars, black locust and birches. (This browse data is from the New York State Department of Environmental Conservation).

Public Domain

I have observed some very interesting aspects of deer behavior in the large, composite herd that crisscrosses through my yard and field throughout the winter. The group is made up of four older does, four yearlings and this year’s now well grown fawns. In the afternoon or early evening the largest doe (who I assume to be the oldest in the group) leads the other deer in single file around the yard and field sampling a great variety of plants. The lead doe browses on the vegetation (the low hanging apple tree branches, the bushy crabapple tree twigs, the arbor vitae, the oak saplings, the hemlocks, the honeysuckle bushes, and so on) and one by one the members of the group walk up to the same spot after she has moved on, feed for a few minutes, and then move on to the next vacated feeding station. The orderliness of the process is amazing.  It has occurred to me that the lead doe possesses the “group knowledge” of what browse is best to take or possibly what order of browse is most digestible. She may also have some knowledge about what intensity of browsing is suitable for the long-term, sustainable productivity of the habitat (but, probably, that is hoping for too much!).  Possibly these feeding behaviors have been habituated in the lead doe by example and repetition in her youth, and, hopefully, they are being drilled into the younger deer. The winter diet of this group (significantly augmented by the sunflower seeds from my bird feeders, of course) has maintained a good number of generations of these animals very well over the twenty-eight winters that I have observed them!

Public Domain

The deer that live in my fields and woodlots are very accustomed to people. They are examples of the “city deer” I wrote about a year or so ago (see Signs of Spring 1, March 1, 2018). These city deer are larger than their “country” cousins and have a much shorter “flight initiation distance” (FID) in response to human approach. The city deer also eat different foods than their more rural counterparts.  A study at Georgia found that city deer consumed a diverse array of often non-native landscaping plants from their urban and suburban habitats. These plants provide them with a diet that is richer in calories and possibly even richer in nutrients than the wild foods of the surrounding rural ecosystems. In  a study in Massachusetts city deer were shown to have ranges that were one tenth of those of rural deer, indicating a much higher quality of habitat and, possibly, a reduced probability of chance encounters with either cars or predators.

City deer in Georgia had low mortality impacts from both natural predators and also human hunters, and a study in Minnesota indicated that city deer not only have a very high survival rate but also that city does have a 93% pregnancy rate typically with twin and even triplet fawns. In Indiana fawn survival rates to 32 weeks were 70% in urban areas (primary cause of fawn deaths were cars) but only 44% in rural areas (primary cause of fawn deaths were coyotes).

In light of all of these benefits to city life it is not surprising that Clark Adams (in Urban Wildlife Management (3rd edition, 2016)) states that 82% of the white-tailed deer in the United States live in urban areas.

Photo by D. Sillman

Some recent research by wildlife biologists at Penn State also looked into the influence of human modified habitats on fawn survival rates (see Penn State News, May 1, 2018). They found that overall only 41% of fawns survive to six months of age, but the more the habitat in which the fawns are reared has been changed by humans, the greater the rate of fawn survival. In fact, for every ten percent increase in human landscape alteration there was a five percent rise in fawn survival rates! Primary factors causing fawn mortality were predators (black bears and coyotes) with collisions with vehicles or farm machinery taking on a much less significant role. Vehicle and machinery deaths rose in more human modified landscapes, but this rise was more than offset by the precipitous decline in losses to predators. Further, these researchers noted that pregnant female deer were actually observed moving from forested, non-human modified habitats into more human modified landscapes where they then had their fawns in the less predator-intensive environment.

Humans are changing so many aspects of the natural word. Cities are sites of intense adaptation, selection and evolution! White-tailed deer (like many other mammals, birds, insects, plants and more!) are taking on distinctive urban traits as they try to live in the developing Anthropocene!

 

 

 

 

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Signs of Winter 13: Where the Wild Things Are Not!

Photo by Benh Lieu Song, Wikimedia Commons

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The World Wildlife Fund for Nature (the “WWF”) released a report this fall (October 2018) that analyzed the 2014 populations of 17,000 vertebrate animal species around the world. This report (the “WWF Living Planet Index”) noted that 4,000 of these vertebrate species showed population declines of 60% or more since 1970.  The causes of any species’ decline are complex, but, according the report’s authors, the overwhelming factor that led to the loss of so many animals was the human destruction or degradation of their natural habitats for agricultural purposes, resource acquisition or industrial development. The most serious declines were observed in Central and South America and in the islands of the Caribbean where wild, vertebrate populations showed a nearly 90% reduction in their numbers of individuals.

The report notes that freshwater vertebrates were particularly hard hit by the consequences of human activity. Further, the authors predict that by 2050 the amount of land area on Earth that is unoccupied by people and unaffected by human activity will fall from the present day’s 25% to just 10%. There will be little room for species that are unable to tolerate the presence of humans and the consequences of human activities.

Vertebrates (mammals, birds, reptiles, amphibians and fish) are the organisms most people recognize as being “animals.” Vertebrates, though, make up a tiny fraction of the numbers of species and total numbers of individuals found in the Kingdom Animalia. There are, by conservative estimates, 1.5 million living animal species on Earth. Of these just a bit over 66,000 are vertebrates (about 4% of the total!). The remaining 96% of animal species are lumped together into an imprecise classification called the “invertebrates.”

Pacific oyster,. Photo by Pixabay

Many of these invertebrates include some of my favorite creatures: earthworms, polychaete worms, clams, oysters, crabs, spiders and mites! But, if we want to find the “poster organisms” for this invertebrate group, the logical animals are the ones that make up 70% of the group’s known species (over 1,000,000 identified to date!). These are, of course, the insects, the most successful group of animals that has ever existed on our planet! Sadly, it turns out that insects are even faring worse than the vertebrates in dealing with the changing features of our “Anthropocene” world!

As I reported this past summer (Signs of Summer 5, July 5, 2018) insect populations declined 76% over the past few decades in the natural preserves around Krefield, Germany. The causes of this decline were all human related: habitat destruction, pollution, pesticide use, etc.  As I wrote in the Signs of Summer post, the relationship between insects and humans is complicated. Many people initially respond or react to the word “insect” with the image of household vermin, a biting/stinging nuisance, a disease transmitting vector, or a crop/garden destroying pest. This emotional reaction might then give way (or in many cases it might not!) to the recognition of all of the “good” that insects do (pollination, decomposition and functioning as a broad base for many important food chains). One third of the food we consume require insect pollinators. That service alone has been assigned a $500 billion a year value, and the monetary calculations for all of the wild plants that are pollinated and all of the food chains fed by insects would probably dwarf that human-food value estimate.

An example that might help to illustrate the importance of insects in decomposition can be found in the history of the European colonization of Australia. The cattle industry in Australia nearly came to an end because native insects were specialized to break down the very fibrous feces of marsupial grazers and could not decompose the dense, wet piles of feces produced by introduced cattle. Dung piles accumulated in the fields and around watering holes driving the cattle away from grass and water. Dung beetles had to be imported in order to clear the fields so that the cattle would freely graze and drink. Dung beetles in the United States, by the way, thankfully a group of native species, are estimated to benefit cattle ranchers to the tune of $380 million a year!

Insects are worth many hundreds of billions of dollars to the world’s economy and make the Earth both productive and inhabitable for all of the other living organisms on it! It turns out, however, that the Krefield, Germany observations are just the beginning of worldwide observations of an ongoing insect apocalypse (see B. Jarvis’ article in the November 27, 2018 issue of the New York Times).

Photo by D. Sillman

In the United States, monarch butterflies have decline 90% in past twenty years (see Signs of Summer 8 (2018) and Signs of Summer 15 (2016)), and the rusty patched bumblebee has declined by 87%. In Great Britain 30 to 60% of the native insect species have significantly reduced ranges, and in California a 46 year butterfly census has shown declines in many species and local extinction of many others. Around the world honey bee hives are being decimated by Colony Collapse Disorder (see Signs of Fall 7,  Signs of Fall 8 and Signs of Fall 11 (2018)), and an article published in Science in 2014 that analyzed insect data from a wide range of published papers concluded that insect populations in these long term studies have declined by 45%.

These declines in insect populations then have reverberations that echo through their ecosystems. In France a number insectivorous bird species that live in farmlands have had precipitous declines in numbers over the past few decades. Partridges were down 80%, nightingales were down 50% and  turtledoves were down 80%. Initial analysis of these data indicated that habitat loss or the increased use of agricultural chemicals were the most likely direct causes of dwindling populations of birds. Later considerations, though, refined these conclusions and indicated that, in fact, these primary causes reduced insect numbers and that these birds then declined due to the lack of food.

Lizard in El Ynque Rain Forest, Puerto Rico. Photo by Jami430. Wikimedia Commons

In the Puerto Rican rain forest as part of a 40 year study of insectivorous lizards, total biomass of insects was regularly collected. In the 1970’s standard insect monitoring methods at specific spots in the rain forest generated 473 mg of insect biomass per collection. Now using these same collection methods at these same sites only 8 mg of insect biomass is collected. The surrounding rain forest seems pristine and undamaged, but its vital insect community is eroding away possibly toward some calamitous, ecological tipping point. The cause in these protected Puerto Rican rain forests is thought to be the rising temperatures due to climate change. The average temperatures in these sites have increased two degrees C over the four decades of the study and extreme heat waves have become more frequent!

Imagine the bleak, post-insect- apocalyptic world that would inevitably follow this massive die off of insects. E. O. Wilson in his 2006 book The Creation: An Appeal to Save Life on Earth does just that:

“The human species survives, able to fall back on wind pollinated grains and marine fishing. But amid widespread starvation during the first decade, human population plunges to a small fraction of their former level. The wars for control of the dwindling resources, the suffering, and the tumultuous decline to dark age barbarism would be unprecedented in human history. Clinging to survival in a devastated world, and trapped in an ecological dark age, the survivors would offer prayers for the return of weeds and bugs.”

Wilson feels that a better name for the Anthropocene (“the age of humans”) is the Eremocene (“the age of loneliness”). It would be the ultimate dystopia!

 

 

 

 

 

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Signs of Winter 11: The Great Backyard Bird Count!

Photo by USFWS, Public Domain

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Starting tomorrow (February 15th) and running until Monday (February 18) the Cornell Laboratory of Ornithology, Birds Studies Canada and the National Audubon Society are sponsoring their annual “citizen’s science” project called “The Great Backyard Bird Count” (GBBC). This word-wide count of birds began in 1998 and has grown in scope and in participation with each passing year. Participants are asked to spend fifteen minutes either stationary at some observation point or walking through a habitat counting and identifying the birds they see. On-line checklists developed by eBird facilitate the reporting of these observations, and the compilation of the data from the observers seems to be nearly instantaneous!

If you are interested in participating in the count click here for more information!

Some highlights of the 2018 bird count include the number of checklists (180,516) and the total number of species observed (6458). Also 28,888,454 individual birds were counted! The number of checklists and the total number of individuals counted were slightly down from the record levels of the previous year, but the total number of species observed in 2018 was significantly greater than 2017.

Northern cardinal (male). Photo by D. Sillman

There was a distinct North America bias to the 2018 count (as has been the case since the count began) because almost two thirds of the checklists come from the United States. The ten most frequently mentioned species on the lists were all very common North American species (led by the northern cardinal, the dark eyed junco, the mourning dove and the American crow), and all of the top ten most numerous birds in the count were also North American species found in large flocks (the count of nearly 5 million snow geese topped this list with 1.6 million Canada geese in second place!). Pennsylvania, by the way, was fourth last year in total number of checklists per state submitted to the count and looking down the list of names of participants who submitted check lists from Pennsylvania counties I found a number of regular readers of this blog! In 2017 Pennsylvania was number two on the checklist list well behind the much more populous California! We need to get more of us out there this year (California may be out of reach, but we can’t let New York and Texas edge us out again!).

Some observations from the 2018 GBBC include the continued southern distribution drift of a number arctic and northern forest dwelling bird species. The pink-footed goose, for example, a Greenland species that a few decades ago was almost never seen in North America now is regularly observed by GBBC participants in Nova Scotia, Connecticut, New York and New Jersey! The Greenland goose, the barnacle goose, and the greater white-fronted goose also were observed in the northeast United States.

Snowy owl. Photo by P. K. Burian. Wikimedia Commons

Snowy owls were abundant in the eastern U.S. and in the Great Lakes region. Red crossbills moved south out of their northern coniferous forests possibly in search of food after a poor seed cone year and were observed all across the United States.  A number of Rocky Mountain species (including Stellar’s jay and the mountain chickadee) were found abundantly in low altitude locations throughout the Great Plains. It is speculated that these birds were also moving because of shortages of food in their higher altitude habitats.

An exotic species, the Eurasian collared dove continued its northwestern spread across the eastern United States and on up into Canada (it has now been repeatedly observed in Nova Scotia). This dove (a native of Europe, India and southern Asia) escaped from a pet store in Barbados in the 1970’s. It has been steadily expanding its range across North America ever since.

Last year’s bird count also detected a number of early “spring” migration pushes. Several species of geese and the sandhill cranes all had begun moving far to the north in spite of the “winter” time frame of the February bird count.

Explore the data and read more about the 2018 GBBC at the GBBC website!

Dark eyed junco, Public Domain

The species that I counted for my two Great Backyard Bird Count lists in 2018 were as common as could be. Most made it onto to top ten “most frequently listed” species. My birding experience didn’t range into wild, exotic discoveries. My birds were cardinals, juncos, blue jays, titmice, chickadees, and crows, and I was very pleased to see them!

Some years ago I was giving a talk at a conference about Deborah’s and my Virtual Nature Trail and the actual, physical nature trail on our campus that was the inspiration for it. At the end of my presentation I was asked a question, “what is special, or unique about this nature trail?” I sensed an undertone to the question of “why would anyone want to go see this trail?” Usually you come up with answers to questions like this much later, but somehow I found the answer right away: There is nothing particularly unique or “special” about this trail, and this is what made it so important. It is the beauty in the ordinary, as Bill Bryson once put it “the low level ecstasy” of the common species and common terrain that make this site so wonderful. Sitting back and seeing what is around you in nature always elevates and inspires you!

And, to me, this appreciation of the “ordinary,” this sense of awe and wonder in the everyday world around us, is what makes the Great Backyard Bird Count and the sight of all of those birds that day in and day out gobble down my sunflower seeds, corn, peanuts and thistle, so special.

 

 

 

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Signs of Winter 10: Winter Hummingbirds!

Photo by D. Sillman

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Here in Western Pennsylvania, no matter how much we might want them, there are no hummingbirds in our yards and gardens during our winter months. Our hummingbirds left back in September or early October  and flew south to Mexico and Central America where they are now feasting on insects, spiders and plant nectar in warm, tropical luxury. Their fall migration is hardwired into their genes and is absolutely essential for their survival. They could not find sufficient food in our cold, snowy winter ecosystems. Shortening day length triggers physiological changes that causes these tiny birds to accumulate fat that will help to power their long flight south. The changes in day lengths also alter the hummingbirds’ behavior making them increasingly restless. Eventually, they reject the full nectar feeders and the flower beds that they had so vigorously fought over all summer and give into an overwhelming urge to fly south.

I have written about our Western Pennsylvania hummingbirds before (see “Hummingbirds”(July 7, 2012) and “Hummingbird Migration”(September 5, 2013)). They are a lively part of our summers. Their departure is an important Sign of Fall and their return is a glorious Sign of Summer!  Imagine how surprised I was out in Seattle in November, 2012 when a robust, male hummingbird dive bombed me while I stood on the balcony of our Air B and B! The hummingbird was the non-migratory “Anna’s hummingbird” (Calypte anna), and its story is a very neat example of the impacts humans can have on the ecology and evolution of another species.

Anna’s hummingbird (male). Photo by USFWS, Public Domain

Anna’s hummingbird’s natural range was the relatively small area of extreme southern California and the northern-most parts of Baja California. In this compact area the birds consumed a wide variety of types of insects and arachnids and drank nectar from a diverse group of flowering plants. They also drank tree sap (especially from trees whose bark had been fractured by feeding woodpeckers or sapsuckers) and readily ate any insects that might have gotten caught in the sticky secretions. Anna’s hummingbird was by necessity an extreme generalist with regard to their dietary preferences because no one plant or insect was present in sufficient abundance to support their entire population, and for similar reasons they were not terribly picky about where they built their nests. The desert to the east and the dry chaparral to the north very effectively restricted their dispersion out from their natural range. Humans, though, eventually changed the vegetational map of both the west coast and the southwest desert and freed Anna’s hummingbird from its ecological confinement.

As people moved into California they planted more and more nectar producing, often exotic, plant species in their yards, parks and gardens. They also planted large numbers of exotic trees which were sources not only of insects but also nectar and tree sap. One type of tree around which large numbers of Anna’s hummingbird are regularly found is the eucalyptus, and eucalyptus trees were extensively planted in California starting in the mid-1800’s.  By the early 1900’s, Anna’s hummingbird had spread out from its restricted habitat range. Its ability to consume so many different types of plant nectars and insects and its broad tolerance of nesting sites allowed it to establish itself in almost any human modified habitat that it encountered.

Anna’s hummingbird (male),. Photo  by B. Matsubara, Wikimedia Commons

Anna’s hummingbird spread north up the coast of California and now is found in abundance up to Vancouver, Canada (with occasional birds found even further north all the way up into Alaska!). To get an historical time perspective on the rate of this spread, Anna’s was first recorded in the Puget Sound area around Seattle in 1964. Anna’s eastward movement through the desert (from one human manufactured oasis to the next) now stretches across Arizona and New Mexico into the western-most reaches of Texas and up into southern Nevada and Utah. Because of their ability to utilize the human constructed, exotic species dominated plant communities of yards and parks, there are many more Anna’s hummingbirds today than there were prior to European colonization of the west coast!

My son and his partner bought a house this summer on the northern edge of Seattle’s city limits. Their yard is a lush garden of flowering plants and shrubs, succulents, and tall evergreen and deciduous trees including many fruit-bearing trees. All summer, the blooming flowers in the yard drew in significant numbers of hummingbirds, and in the fall, Joe and Marlee hung nectar feeders outside their front window and began to draw in even more.

There are two species of hummingbirds that are resident in the Seattle area: Anna’s hummingbird and the rufous hummingbird (Selasphorus rufus). Anna’s is larger (almost four inches long compared to the just under or just over three inch length of the rufous), and the Anna’s males are distinctively marked with metallic green backs, heads and sides and bright red throats and crowns. The female Anna’s also have green backs but with much more subdued gray bellies. The female Anna’s, though, unusually for female hummingbirds, may also have some spots of red on their throats. The male rufous hummingbird glows bright orange in the full sunlight and has an iridescent red throat. The rufous females are more muted in color with green backs and heads and rust colored sides. The immatures of both Anna’s and rufous resemble the females in plumage.

Rufous hummingbird (male). Photo by A. Reago and C. McClarren, Wikimedia Commons

The rufous hummingbird, unlike Anna’s, is migratory. It leaves its northern breeding regions in the fall and flies to the southwestern rim of the United States and northern Mexico to overwinter. Migration in this species, like our ruby-throated hummingbird here in Pennsylvania, is obligatory. So as winter comes on, the only hummingbirds visiting the nectar feeders in Seattle will be Anna’s, but the mix of adult males, adult females and immatures may make the flock of hummingbirds seem diverse even though it is a monospecific assemblage. A flock of hummingbirds, by the way, can be called a bouquet, or a glimmer, or a glittering, or a shimmer!

The Pacific Northwest in spite of its high latitude is kept relatively warm in the winter by the proximity of the Pacific Ocean. There are some days, though, and many nights when temperatures drop below freezing and when snow may actually fall on coastal locations. Anna’s hummingbird is able to tolerate these extreme conditions by utilizing two physiological adaptations: 1. It can quickly convert the sucrose that consumes during the day into fat (which then serves as both a body insulator and also an efficient metabolic fuel for the long, cold night), and 2. It can go into a low metabolic rate torpor at night to conserve energy.

Witch hazel in winter bloom. Photo by Downtowngal, Wikimedia Commons

Humans can reduce the metabolic stress on Anna’s hummingbird by planting winter blooming plants in their yards (plants like winter jasmine, winter blooming grapes or witch hazel), or by maintaining outside nectar feeders throughout the winter. Keeping the nectar bottle from freezing is vital and the Seattle Audubon Society recommends using either plumber’s heat tape, a hanging, shop “trouble” light, or even a coiled up mass of outdoor Christmas lights to keep the nectar above freezing. Duct taping a hand-warmer packet to the side of the feeders is also a good short-term heat fix against nectar freezing! Taking the feeders in each evening is also a possibility, but you have to remember that hummingbirds get up VERY early in the morning!  The Seattle Audubon also stresses that the nectar should only be made with cane sugar (sucrose) and only be mixed in a one part sugar to four parts water ratio. Higher sugar concentrations may actually make it hard for the hummingbird to suck the sugar water up across their tongues and may even do damage to the bird’s kidneys and liver.

There are so many wonderful things about the Pacific Northwest! The mountains, the rocky ocean shores, the vast forests, the hiking, the food, the craft beers and the coffee! It seems unfair that they get to have winter hummingbirds, too!

 

 

 

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Signs of Winter 9: Seventh Annual House Cat Day!

Taz. Photo by D. Sillman

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Six years ago I wrote about Groundhog Day and suggested that we change this early February day-of-prediction to focus not on an animal that is sound asleep in his grass-lined burrow dreaming of gardens to ravage, but instead that we look at an animal with whom we could more naturally base an ecologically or culturally significant day of hope for the coming spring.

I went through the cases for using a number of different species for our new holiday. Robins, for example, are the classical spring arrival species, but many of our Western Pennsylvania robins spend the winter locally in nearby refuges. On mild, sunny days throughout the winter flocks of robins drop into my yard and check out the leaf piles, but then they quickly depart especially if it starts snowing on them! With their sudden appearances and departures, robins might not be a reliable enough species on which to base our new holiday.

Bela. Photo by M. Hamilton

I also suggested that bumblebees might be an excellent indicator species in recognition of the early emergence of the hibernating queens and their remarkable ability to generate body heat and survive (usually) that initial cold flight of early spring. If we force the queen bumblebees out on early February flights, though, they probably would all freeze to death. Not a very happy thought for a day of celebration!

I also thought about scarlet tanagers as a species representing the long distance migrators that return to our northern habitats after a winter respite in South America. The scarlet tanagers, though, will not be around until April (much too late to get any publicity about the coming spring).

Someone last year suggested stink bugs emerging from their hibernation hideouts in our houses might be a “good” sign of spring. I am of the opinion, though, that stink bugs are not a “good” sign of anything and am not seriously considering that well intentioned but obviously misguided suggestion.

Mora. Photo by M. Hamilton

Taking all of this into consideration, I settled on what was, to me anyway, the most logical and most reliable and most available indicator species among us. That species, of course, is the housecat (Felis catus).

Cats are the most popular house pet in the United States (the Humane Society estimates that there 74 to 86 million house cats in the U.S. (as compared to “only” 70 to 78 million dogs)). As I wrote in my November 24, 2016 blog (“Our Other Best Friend”) cats have a complex relationship with humans and may be the only animal species that has chosen us as a co-evolutionary partner rather than vice-versa (hence the hypothesis that cats are not really domesticated at all but are wild animals exploiting our habitats and resources!). The resemblance of domesticated cats to their closely related wild species, the focus of many cats on places rather than people, and their perceived aloofness and self-absorption are factors that cause people to have intense feelings (both positive and negative) about cats.

A cat’s inherent love of sunshine and warmth, though, make them a perfect biological agent to help us predict the nearness of the coming warm seasons! And, since they are living in our houses year round, they are available for predictive experimentation!

Mazie. Photo by D. Sillman

So, six years ago on February 2, 2013 I took one of my cats, Mazie, out into the snow-covered front yard (I tried to take both of my cats, but Taz sensed that something was up and disappeared into one of her magical hiding places somewhere in the house). I put Mazie down in the yard (on a nice dry towel!), and left the front porch door open. If Mazie ran for the porch, then we would have six more weeks of winter. If she stayed on her towel or started walking around in the yard thus avoiding a dash back into the house, then spring was just around the corner.

I was amazed how fast she ran back into the house! But, that year the weather suddenly turned warm. March temperatures set record breaking highs (I even remember a day when it nearly got up to ninety degrees!).  Maybe our predictive model was not articulated correctly.

Binx and Mora. Photo by M. Hamilton

In 2014 and 2015 I followed the same experimental procedure, and Mazie, as I reported on this blog, responded with equal speed and agility and got back into the house almost before Deborah could take the lens cap off of her camera. In both of these years winter hung on grimly well into March. Mazie’s predictions, then, fit the observed phenomenon.

In 2016, though, Mazie’s response to the front yard was entirely different. She stepped off her towel and explored the front flowerbed, jumped at some little Pardosa spiders that were running around in the grass and seemed to enjoy herself very much. The early onset of spring that this behavior predicted came about! We had a mild, pleasant March and April and eased our way into a warm, early summer.

A definite “no!” Photo by D. Sillman

In 2017  Mazie not only ran back into the porch but she headed straight for the basement and hid in a box in the furnace room for several hours! Her reaction, though, did not match the resulting weather as both February and March had average monthly highs of 66 and 67 degrees! Definitely an early (and sustained) Spring!

Last year (2018), Mazie ran from the cold and snow and predicted six more weeks of winter. The rest of February was a roller coaster of temperatures bouncing from the teens all the way to 77 degrees on Feb 20! March, then, was colder than February with quite a bit of snow. The month ended, though, with temperatures in the 60’s. Sounds like Mazie nailed her prediction again!   Our grand-cats (Bella and Mora) in Denver were split on their predictions, and our cat reporters in California told us “what winter?”

So Mazie has been correct about the onset of Spring 4 out of 6 times! We’ll see how it goes this year!

Send on your own experiences and observations!

Happy Winter, everyone! (But, it’s almost time to start thinking about Spring!)

(House Cat Day 2019 is once again dedicated to Taz and Binx. They will be greatly missed forever!)

 

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Signs of Winter 8: Beavers of Roaring Run!

Photo by D. Sillman

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The Roaring Run Trail runs along the northern bank of the Kiskiminetas River just outside of the town of Apollo. A few weeks ago, Carl Meyerhuber and I were walking the trail and noticed abundant beaver sign along the stream bank starting about a quarter of mile from the parking area. Numerous small trees (mostly red maples, yellow poplars and yellow birches) were cut down to pointed stumps a foot to a foot and half tall. Piles of fresh wood chips surrounded each stump, but the rest of tree and all of its canopy branches were gone. There was also fresh gnaw sign on the trunks of several large (a foot and half trunk diameter) black cherry trees and a number of medium sized maples and birches. I hadn’t see any of this tree damage through the fall even though I had been down on this trail almost daily either walking or riding my bike. Possibly, the seasonal die-back of the Japanese knotweed that thickly covers most of this bank has proceeded just enough to let us glimpse what is happening to the trees.

We can now see, though, that the Roaring Run beavers are active!

Photo by Steve, Wikimedia Commons

North American beavers ( Castor canadensis) are the second largest, living rodent in the world. Adult beavers average between thirty-four and sixty-five pounds (although, according to the Pennsylvania Game Commission’s 2011 report on beaver management in the state, several beavers over seventy pounds have been trapped in Pennsylvania). They are considered to be obligatorily vegetarians although there are reports of them opportunistically scavenging dead fish and other carrion in their stream-side habitats. All spring and summer they eat a wide variety of water plants but survive through the winter by consuming the inner bark of large number of tree species (especially aspen, red maple (and other maples, too), willow, birch and alder).

In the early winter months beavers forage out from their dens and take down as many small trees as they can. They may immediately consume the inner bark of some of these trees, or they may collect and cache the cut sticks, branches and slender, tree trunks in the rivers or ponds near their dens. They rely on these underwater caches for their winter food when conditions do not allow them to forage freely about.

Beavers were once extremely abundant in Pennsylvania and all across North America. Uncontrolled trapping through the Eighteenth and Nineteenth Centuries, though, nearly drove them into extinction. There were once twenty-four or possibly twenty-five subspecies of North American beavers across the continent. Many of these subspecies have been lost in part due to their local extinction by trapping and also as a consequence of uncontrolled re-introduction programs that have led to the extensive inter-mixing of different genetic lines. It is estimated that prior to European colonization of North America there were 200 to 400 million beavers in a wide range of habitats from far northern Canada and Alaska down into Mexico. Today there are approximately ten to fifteen million beaver in North America.

Bank beaver den. Photo by D. Sillman

Beaver are nocturnal and can be observed coming into or out of their dens at dawn and at dusk. Their dens may take on a variety of conformations but are almost always associated with a protective stick-piled, mud-cemented palisade over an underwater opening. Classically, beavers build dams across small streams . These dams then back up stream water to generate a protective pond. The den is then built right into the superstructure of the dam itself. Beavers also, though, build dens on small islands in ponds and lakes (like the one at Harrison Hills Park that I wrote about in January 2016 (Signs of Winter 8)). They also build dens on larger rivers, like the Kiski. These rivers are too broad and too fast flowing to be dammed up so the beavers dig burrows into the stream bank (hence the common name “bank beaver” for these large-river dwelling beavers). They then shield the burrow entrance with a cemented pile of sticks. It is remarkable how this rodent is able to create such different functional constructions in such a wide range of different conditions!

Beaver dams and ponds are extremely important components of their ecosystems. They help to control high water flow rates in the spring and store water to keep streams flowing in the summer. They greatly improve water quality by facilitating  sedimentation and the control of pollutants (including bacteria from the feces of wild and domestic grazing animals and nitrogen and phosphates from agricultural field runoff). They generate vast areas of open water that support a wide variety of birds, mammals, insects and fish. Beaver dams and ponds have been shown in numerous studies to be extremely important factors in the overall abundance and success of wild trout and salmon throughout North America. They are also extremely important in stream rehabilitation programs.

Photo by D. Sillman

Although the bank beavers do not have these same kinds of impacts on their streams as the dam and pond building beavers, they still make significant contributions to the overall vitality of their ecosystems. Beavers grazing on trees in the stream-side forest generate sun gaps and stimulate seed dispersal and germination. The edges of these sun gaps form dense, vegetative ecotones that are prime nesting and feeding habitats for many species of birds. Also, many of the tree species that the beavers take down stump or root-sprout to form dense coppices of young trees along the stream bank. These tree thickets are also ideal habitats for many species of birds. Also large trees

Beaver sign on black cherry tree. Photo by D. Sillman

that are girdled and killed by beavers (the likely fate, for example, of those large black cherry trees that have gnawed on along the Kiski) become prime feeding and nesting habitats for woodpeckers. The holes the woodpeckers make in these trees can then be utilized by a myriad of cavity nesting bird species.

The entire forest ecosystem becomes more dynamic and diverse because the presence and activity of the beavers!

We’ll keep an eye on the tree growth in the beaver trimmed bank section of the Kiski! Hopefully, we’ll see more growing there than just knotweed!

And, just to finish up this discussion about beavers: In an article in the Washington Post last summer (August 9, 2018) the impact of beavers introduced into the forests at the southern tip of South America was described. In 1946 a small number of North America beavers were released in the Argentinian side of Tierra del Fuego in order to “enrich” the local wildlife.” These beavers quickly established themselves and began to remake the Tierra del Fuego landscape. They also swam across the Strait of Magellan and invaded the shrub and grasslands of Patagonia. There are now 200,000 beavers in southern Argentina and Chile! Interestingly, these beavers are even damming rivers in places where there are no trees! They weave grasses and shrub branches together to make their dams and dens!  The cost of removing these beavers from these ecosystems is being balanced against the on-going destruction of the habitat structure and species composition of the original ecosystems!

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Signs of Winter 7: A Snow Hike at Laurel Hill

Photo by D. Sillman

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The winter is a time when many of us don’t even think about going outside to walk or hike. Much of this behavior is habit, I think. It is more than possible to layer up with comfortable, warm clothing and put on suitable boots that will stand up to even the coldest days of our winter. Properly clad you can get in some very nice miles along your favorite trails and paths. You need to watch for ice patches and avoid slips and falls, of course. You also need to anticipate steep slopes and maybe find routes that are relatively level. One cold, January afternoon many years ago I got stuck in the ravine of our campus’ Nature Trail unable to climb up the icy path (I was wearing some smooth bottomed tennis shoes!). I ended up pulling myself up through the scrubby underbrush well off the trail. Hanging on to the woody stems was the only thing that kept me from continually sliding back down the slope toward the creek.

Some of trails near rivers and creeks get a thick coating of ice that can persist until March. You need to find trails that stay clear or ones that are simply snow covered. A good winter hiking stick with an ice-tip is a great tool for a winter walk. Wool socks are also a good idea, and you want to be sure that your hands and face are well covered so that there are no problems with frostbite.

There are many advantages to winter hiking: the lack of crowds, the lack of ticks and biting flies, and the incredible quiet and peacefulness of the winter woods! Deborah and I have done a number of “snow hikes” with our friends Rob and Michele and have written about them on this blog. Take a look at the Wolf Rocks hike (November 14, 2014) or the Spruce Flats Bogs hike (November 21, 2014) or the Hemlocks and Snow Fleas hike (February 2, 2014) for a feel of some really nice winter hikes in the woods.

Keeping this history alive, the four of us decided to go for another winter hike back in mid-December!

Photo by D. Sillman

Earlier in the week it had sleeted and snowed, so there was ice on the roads and parking areas and a couple of inches of crusty snow on the trails. It was cold (the high that day was about 19 degrees F), but it wasn’t windy, and we were all well wrapped in our winter gear. Deborah and Michele even had glove warmers (which stayed hot well into the evening!).

We drove down to Laurel Hill State Park. The original forest on Laurel Hill had been dominated by eastern hemlocks, and there is a small stand of surviving hemlocks that we often visit but decided that the climb up and down that trail might be too icy today.

The site’s primal forest was clear cut in the late 1880’s leaving almost all of Laurel Hill a dry, brushy wasteland. The piles of discarded branch wood regularly burned often in extensive wildfires that spread over the ridges and valleys. In the early decades of the Twentieth Century the view of this ravaged ecosystem led Gifford Pinchot (the founder of the U.S. Forest Service and an eventual governor of Pennsylvania) to describe the uncontrolled logging of the Pennsylvania forests as “an orgy of forest destruction.”

It was also a fundamental lesson in forest ecology. The lack of trees allowed the rain to breakup and erode the underlying soil not only removing vital nutrients from the terrestrial ecosystems but also silting up the local streams and killing off fish and aquatic invertebrates. Further, the lack of water retention in the terrestrial ecosystems allowed rainwater to run unchecked into the rivers causing massive flooding with great property and human life losses. The Johnstown Flood of 1889 was at least partially attributable to the massive deforestation of these and neighboring ridges.

Photo by D. Sillman

We are fortunate, though, for two things: 1. Our climate and surrounding ecosystems enabled certain tree species (like the red maples, black cherries, and red oaks) to rapidly re-establish themselves in the charred habitats, and 2. There were people (like the Western Pennsylvania Conservancy) and programs (like the Works Progress Administration and the Civilian Conservation Corps (or “CCC”)) that invested time, money, and energy into the rehabilitation and resurrection of these ecosystems. What we see around us today is the result of their foresight and efforts.

Many of the trees that make up this incredibly evenly aged secondary forest are relatively short lived. Black cherry trees, an important part of the “Allegheny Hardwood” association, live on average 100 years. Very few specimens of black cherry are ever found older than 130 years (tree life estimates are from Virginia Tech’s Department of Forest Resources web site). Along the trails of Laurel Hill Park (and almost everywhere else in Western Pennsylvania, too) you see abundant woodpecker damage to standing black cherries and increasingly large numbers of standing, dead trees. Red maples are the most numerically abundant trees in our Western Pennsylvania forests. They have an average life span of about 130 years and seldom live to be older than 150. These trees, then, are also well past their primes! These rich, apparently healthy forests around us are nearing the ends of their expected life spans.

What these forest will turn into next is a topic of great interest and concern!

We drove to the Pump House Trail and parked in a very icy parking area. It was comically difficult to walk across the iced-up gravel to get to the trail head! There were a couple of pickup trucks in the lot when we arrived and one deer hunter coming in out of the woods (empty handed). Rob had hooked his orange hat onto his coat, and I thought about the orange vests I had intended to bring (they were hanging warm and safe in my garage back home). We planned to stay on the large trails and make as much “people” noise as possible. We could always hide behind Rob and his hat at need! We spent two hours walking the loop down to the pump house pond and up onto the ridge. When we returned all of the pickups had gone.

Photo by D. Sillman

On the hike we stopped at the CCC-built dam and crossed the sequence of the narrow, snow-covered, log, foot- bridges that spanned the winding track of the fast-running Jones Mill Run. The run was bordered and, in places, covered with a layer of ice. There were some beautiful icicle sculptures growing beside the fast running creek. In between log bridges the trail was stabilized by a layer of large, ice covered rocks. Walking very difficult. You had to keep your eyes on the path’s surface to keep from falling or turning an ankle. Every once and a while we stopped so that we could look around at the scenery.

Over the two hours of the hike we saw no birds, no squirrels, no deer and very few other people. We didn’t see any “snow fleas” today either. We did meet a young sheepdog (and his owner) to whom we yielded the right-of-way on one of the log bridges. We weren’t sure if the sheepdog would have seen us standing in front of him if we had tried to cross before he did! The thought of being knocked into the cold water of the creek was very unpleasant!

It was an incredibly pleasant hike! We then went to a nice warm tavern and had a sandwich and a glass of local ale. Winter hikes are the best!

 

 

 

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Signs of Winter 6: Chocolate

Photo by 4028mdk09. Wikimedia Commons

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Winter is a great time to talk about chocolate. There is nothing like a cup of cocoa or a heavily-chocolated mocha coffee to help ease away the cold of these dark days. Also munching chocolate bars while hiking in the snowy woods (or even when you are just looking out the window at the snow!) helps you to feel at peace with the season.

Chocolate is the well processed product of the seeds of the cacao tree. Cacao trees are native to Mexico and Central and South America, and the use of chocolate can be dated back to 1500 BC and the Olmec civilization of present day Mexico. Recent genetic studies suggest that the cacao originated in the Amazon basin but spread quickly along the active trade routes between the early Mesoamerican societies.

Cacao tree. Photo by International Institute of Tropical Agriculture, Flickr

The cacao tree (Theobroma cacao) is a small (15 to 28 foot tall), evergreen, understory tree of wet tropical forests. They have very narrow temperature tolerances (optimally 70 to 90 degrees F with 59 degrees F as the lethal low-tolerance point), and require a great deal of moisture (optimally around 80 inches of rainfall a year). Cacao, therefore, can only be grown in the tropics (the 20 degree N and S latitude band around the equator).  Different strains of cacao make different kinds of seed pods, but all of their seeds can all be processed into chocolate.

Chocolate is incredibly popular around the world. An estimated one billion people consume chocolate on any given day! The average American eats between 10 and 12 pounds of chocolate a year (different sources have slightly different estimates!). For comparison, though, the average person in Switzerland eats almost 20 pounds of chocolate a year! Who wants to emigrate?

Although cacao trees are native to the Americas, 75% of today’s chocolate is grown in Africa (the Ivory Coast is the number one producer). Annual worldwide sales of chocolate total to almost 100 billion dollars. It is estimated that 50 million people around the world depend on chocolate for their livelihoods. Many of these worldwide  millions are poor, subsistence farmers, and the rise and fall of the chocolate industry can have significant impacts on these producers!

In the 1940’s chocolate producers settled on a very select array of cacao trees as their preferred sources of the raw material for chocolate manufacturing. The consequence of this was an increase in the quality and reliability of the raw material for chocolate, but this consistency came at the cost of greatly limiting the genetic diversity of the cacao plantations. The narrow set of cacao clones selected and planted around the world set up a potential catastrophe if some pathogen should attack the narrow resistance base of the trees or if some environmental variable should shift conditions away from the very narrow range of optimal or tolerable conditions of the clones.

And, unfortunately, both of these negative scenarios came about!

Frosty pod rot. Photo by G. Cubillo. Scienta Ricerca Open Access Directory

In the 1970’s cacao trees in Costa Rica were attacked by a fungus (Monliophthora roreri) that causes a disease called “frosty pod rot.”  The impact on Central America chocolate production was sudden and severe (there was a 96% decline in cacao production in Costa Rica which effectively destroyed the chocolate industry there!). The fungus spread through Central and South America and even skipped over to islands of the Caribbean (Jamaica reported frosty pod rot in 2016). The barrier of the Atlantic Ocean did not seem sufficient to prevent the spread of this devastating fungus to the susceptible trees that had been extensively planted in Africa.

Fortunately, there were a few people with forethought and a solid grasp of the potential dangers of clonal chocolate agriculture. In Turrialba, Costa Rica there is an arboretum called the “International Cacao Collection” in which 1235 types of cacao trees are grown. This arboretum houses the great range of genetic diversity of  Theobroma cacao. The arboretum , though, is constantly short of funds (most grants from the large chocolate manufacturers go to research on faster growing, more productive hybrids rather than maintaining this fundamental genetic reserve), and it barely has sufficient means to keep the trees alive and healthy.

Dr. Wilbert Phillips-Mora was the head of the Cacao Genetic Improvement Program at the Tropical Agricultural Research and Higher Education Center in Costa Rica up until his retirement three years ago. Dr. Phillips-Mora was featured last year in a New York Times article about chocolate production (September 25, 2017).

In the 1980’s Dr. Phillips-Mora worked to identify specific types of cacao trees that exhibited disease resistance, including resistance to the frosty pod rot fungus. He painstakingly crossbred and hybridized these disease resistant strains of cacao and finally, after decades of work, developed a handful of hybrids that had both disease resistance and high seed yields but also produced high quality, good tasting chocolate. These hybrids (which produce three to six times more cacao than regular trees) are now being planted all across Central America, Mexico and Brazil.

Photo by Nestle. Flickr.

There are many on-going problems with these hybrids. They do not self-pollinate (and, therefore, do not always breed true), some produce very small beans, and some may have adverse reactions to the arrays of pathogens that are endemic in the wide variety of geographic regions into which the trees are being introduced. These problems, though, are being studied and managed.

After his retirement, Dr. Phillips-Mora stayed on in Turrialba to oversee the International Cacao Collection arboretum. He is dedicated to the preservation of this vital resource in the fight to save the international chocolate industry.

Last Spring there was an article in Penn State News (May 9, 2018) about some other attempts to save the cacao tree. Researchers at Penn State are using the gene insertion tool CRISPR to try to breed cacao trees that will be resistant to disease and also tolerant of the warmer tropical temperatures predicted by global climate change models. These researchers recognize that cocoa production has reached a potential limit with regard to land, water and fertilizer use and that the trees themselves must now be changed in order to maintain or potentially increase the worldwide production of cocoa. CRISPR may enable these researchers to find a tree type much more rapidly than if they were still only using classical tree hybridizations methods.

So here we are in the time of chocolate. There are suggestions, though, that chocolate, like coffee (see “Signs of Spring 6,” March 23, 2017), might not survive our ongoing abuse of our planet. Let’s hope we can stay ahead of changes we are causing and enjoy our mocha coffees (and more!) forever!

 

 

 

 

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