Signs of Spring 10: Vernal Pools (and more!)

H. crucifer Photo by USGS (Public Domain)

H. crucifer Photo by USGS (Public Domain)

Spring frogs are important harbingers of the season in Western Pennsylvania, and Deborah and I listen for them carefully. The Spring Peepers (Hyla crucifer) are usually the first frogs to make their presence known. They begin their soft, peeping group choruses in and around small ponds and wetlands as soon as there are some warm, spring evenings. This year, however, we didn’t hear any peepers out in the usual places around our home.  This past winter’s lack of snow fall (leading to a low level of spring snow melt) and our very dry March and April may have cut into available water habitats for these little frogs to use as mating sites.

Gray tree frogs (Hyla versicolor) typically start their resonating trills soon after the peepers. This year we did hear some tree frogs out around our house in spite of absence of peepers, but their numbers and volumes were greatly reduced from previous years.  In some years the tree frogs continue to trill well into the summer. We’ll see if they can re-group or gather new strength.

There is a third frog that we regularly look for in this winter-to-spring transition: the wood frog (Rana sylvatica). We have to drive some distance, though, in order to see and hear wood frogs because they don’t do well in areas that have too many people.  They need dense, quiet woodlands with lots of leaves to hide under and lots of low spots for their spring mating pools!

Photo by D. Sillman

Photo by D. Sillman

So, Deborah and I drove down to Ohiopyle last weekend and met up with Rob and Michele for our annual, spring hike around Ferncliff Peninsula. We were looking for any new (or different) signs of spring, but in particular we wanted to see if we could find the wood frogs that were so abundant here three years ago (on a warm afternoon hike in late March 2013). The timing of the emergence of the wood frogs from hibernation and their frenetic mating in the temporary, spring (or “vernal”) pools of water (accompanied not by trilling or peeping but by a call that sounds like the quacking of a duck!) are all influenced by air temperatures and the abundance of surface water. Because of our very non-typical winter and spring, we were curious if there would be any amphibians at all! Also, incompletely filled pools might dry out before the aquatic larvae of the breeding amphibians have had sufficient time to develop legs and lungs. This disastrous outcome could wipe out an entire year’s crop of young amphibians.

Photo by D. Sillman

Photo by D. Sillman

We walked out onto the Ferncliff Peninsula at Ohiopyle. The day was getting warm, and it felt good when the sun finally came out from behind the clouds. The first part of the hike was over the far shore’s rocks and boulders along the Youghiogheny River at the Ohiopyle Falls. There was quite a bit of new flood debris along the shore, but Rob commented that the water level seemed lower than usual and the river rocks seemed more exposed and extensive than in previous years. Possibly in response to our near-drought more water is being held back behind the Youghiogheny Dam.

The isolated pools up and around the shoreline rocks, though, were full of life. Hundreds of tiny, black tadpoles were clustered together in the sunlit sections of the pool. Water striders were whirling and skimming across the still water and were actively bouncing into each other (establishing territories or mating?) and searching for food.  There were several types of eggs in the pool including the very distinctive cloudy and opaque eggs masses of the spotted salamander. Rob saw a small, brown salamander hiding in the brown leaves at the bottom of one of the pools. He poked it with the tip of his hiking stick (very gently!) and it swam to the back of the pool and buried itself in the leaves.

Photo by D. Sillman

Red Trillium Photo by D. Sillman

 

The trail climbed up away from the rocks and headed out along one side of the peninsula. The red maples and yellow poplars were all just starting to leaf out. They were covered with light green halos of tiny leaves. The abundant hemlocks and the scattered white pines made dark, bordering lines of green around the spindly hardwoods, and thick bunches of rhododendron bushes added their waxy deep greens to the landscape. The greens stood out sharply against the overwhelming brown ground cover of scattered, dead leaves. We also saw some spring wildflowers: red trillium, sessile leafed bellwort, and star chickweed (all pictured above and below).

 

Sessile leafed bellwort Photo by D. Sillman

Sessile leafed bellwort Photo by D. Sillman

Every time we hike this trail something happens to separate Deborah and Michele (who inevitably walk out ahead at a rapid pace) from Rob and I (who lumber along at our slow (but steady!) pace). When we made the big turn in the trail after inching along a narrow rock side trail that ran along a steep drop to the river, we got a glimpse of two people walking up and over a trail that ran up to the top of the peninsula. We thought that Michele and Deborah had taken the turn to go up, so we did too. Unfortunately we realized (after fifteen minutes or so of scrambling up the rocky trail) that the people we were following were not Michele and Deborah. We hope that they didn’t notice that we were stalking them!

We cut back down to the lower Ferncliff Trail, but by then were hopelessly separated from Deborah and Michele. Rob’s cell phone died in mid-text “where are…?” and so we plodded on following a couple and

Star chickweed Photo by D. Sillman

Star chickweed Photo by D. Sillman

their three little girls trying not to fall too far behind them!  Rob and I continued on the Ferncliff Trail and eventually re-made contact with Deborah and Michele near the trail’s end parking lot.

The Ferncliff Trail connects to the Great Allegheny Passage Trail. This is where we had seen the series of vernal pools full of wood frogs back in 2013. We checked them out very hopefully but were very disappointed by the water levels and quality. The pools were about half of their widths and depths of three years ago and were choked with algae and sediment and bits of litter and tossed debris. We saw neither frogs nor any egg masses nor any tadpoles. I don’t think that it will be a good year for amphibians in Western Pennsylvania!

Vernal pools are an important part of the forest habitats throughout the Eastern United States. They are small, shallow bodies of water with fluctuating water levels. Typically, these pools attain their maximum depths and volumes in the spring and their minimum depths and volumes in the summer. Many of these pools completely dry up especially in drought years or years of meager snow fall (like 2016!). A vernal pool must, according to Elizabeth Colburn in her excellent book Vernal Pools: Natural History and Conservation (2014), stay flooded for two or three continuous months, so it is, indeed, something more than just a rain puddle.

Vernal pools have no continuous inflows or outflows. They exist as isolated basins in the midst of their woodland ecosystems. This disconnection to streams and the possibility (or, more appropriately, the probability) of drying out generates a critical ecological feature of these pools: they do not have fish. And, this distinctive absence generates an aquatic habitat especially conducive to the development of a wide variety of amphibians whose eggs and immature life stages are heavily preyed upon by many fish species.

Vernal pools are greatly affected by the types and densities of the trees that surround them.  The chemical nature of the prevailing leaf species influences the acidity, turbidity and nutrient levels of the pool waters.  The history of a pool and the regularity and predictability of its occurrence and duration also has profound influences on the diversity and abundance of its breeding amphibians.

These pools in the Ohiopyle forests have been in place for many years and rely on sufficient melt and spring rain to fill them sufficiently. Let’s hope that next winter is a bit more snowy and that the March and April rains are more abundant. We need to hear ALL of the spring frogs next year!

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Signs of Spring 9: Red Maples (part 2)

Photo by D. Sillman

Photo by D. Sillman

I am looking out across a broad river valley here in Western Pennsylvania. At least one third of the trees I see are red maples (the photo to the left was taken about a month after the photo in last week’s blog). Last week I wrote about the amazing reproductive potential of the red maple and the readiness of its seeds to germinate and survive as seedlings in almost any natural and human generated habitat. Now let’s talk about the ultimate forest sculpting force in Pennsylvania today: the white-tailed deer.

Red maple seedlings are extensively browsed by deer in the winter. So, there is a large advantage for a seedling to grow as fast as possible in order to stretch itself above the browse level. Growth rates of red maples are prodigious: one foot height increases in the first year, two feet per year after that. Red maples, though, are also able to sprout after the above ground stem has been damaged. After a seedling has been browsed by a deer, for example, that individual can actually re-sprout at a growth rate of three feet per year! Sprouts, initially, have a faster growth rate than seedlings! There may actually be a selective advantage for a seedling to be browsed so that this accelerated growth spurt can be achieved!

Photo by D. Sillman

Photo by D. Sillman

The symbiosis between deer and red maples, then, is complex and, on the surface, seemingly contradictory. Deer eat red maples voraciously in the winter. But this winter browsing may actually stimulate those red maple individuals that are capable of the most robust sprouting response, to attain dominance in their ecosystem! Further, the sheer numbers of red maple seedlings in a forest floor community make it likely, especially in years of abundant browse, that at least some of the red maple seedlings will be passed over by the deer and, thus be able to survive to grow. Tree species that generate smaller numbers of seedlings are less likely to survive this intense survival filter of deer browsing.

Many insects feed on red maples, but few of these insects are serious, lethal pests. Gypsy moth larvae, for example, feed preferentially on oak leaves over red maple leaves possibly because of certain alkaloid chemicals that are present in the red maple leaf tissues. These alkaloids may also be an important in the red maple’s resistance against excessive summer leaf browsing by deer.

Public Domain

Public Domain

Red maples are extremely sensitive to fire. All of its life stages (seedling, sapling, “pole” tree, and mature tree) are easily damaged and killed by forest fires. Fire is a very effective way by which a forested ecosystem can be scoured clean of red maples! The minimal presence of red maples in pre-settlement forests and their predominant confinement to very wet habitats may be explained by the regular occurrence of fires in the drier habitats. Some of these fires, in fact, are thought to have been set by Native Americans in a management strategy that increased the dominance of oaks and sculpted the physical structure of the forest itself into a configuration more conducive to hunting and the support of deer populations. The wide-spread suppression of forest fires throughout the twentieth century may be an extremely significant factor in understanding the expanding distribution and abundance of red maples.

The pre-settlement forests of Pennsylvania were dominated by oaks (especially white oak), American chestnut, eastern hemlocks, and white pines. All of these tree species were extensively cut for timber, mine props, railroad ties, firewood, charcoal, tannins and other wood chemicals, and paper pulp. The oaks in the re-growing, secondary forests were then exposed to intense browse pressures by the re-surging white-tailed deer populations, and defoliated often fatally by the explosive outbreaks of the introduced gypsy moths. The suppression of forest fires also removed an on-going environmental factor that favored the dynamic persistence of the oak forest. The American chestnut was functionally exterminated as a potential canopy tree by the twentieth century expansion of the introduced fungus that caused chestnut blight. Eastern hemlocks were logged into near extinction in the state and, most significantly, the moist, highly shaded forest floor microhabitat in which their extremely specialized seeds and seedlings could germinate and grow was destroyed by the clear cutting and subsequent soil and litter erosion and drying exposure to direct sunlight. White pines thrived on sites with coarse, well drained soils and relied on periodic fires to reset their successional sequences and maintain a site consistency of white pines. Fire suppression, then, also limited the ability of white pines to reestablish their “pineries.”

Photo by D. Sillman

Photo by D. Sillman

The pre-settlement forests, then, were densely populated with highly specialized trees that had established and maintained themselves in their habitats. These tree species modified the characteristics of their habitats to favor their growth and survival. These species were also adapted to respond to the catastrophic but regularly occurring disturbance events that beset their ecosystems. Settlement, then, changed everything. The suppression of fire, the destruction of the ancient, persisting seed beds of the forest floor, and the introduction of exotic insects and diseases altered the stress and selection matrix of these forests possibly forever.  Tree species with broader tolerance ranges especially with regard to reproductive processes and stages were now favored. And, the red maple is acknowledged to be the “ultimate generalist.”

So, the question I have been pondering here in the shade of this wonderful red maple in the company of generation after generation of red maples, is “why are they here?” and “why are they everywhere I look?”

The destruction of the pre-settlement forest opened many niches. The failure of the hemlocks and white pines to reproduce, the loss of the American chestnut, and the on-going failure of the oak forest to re-establish itself reduced competition, and the incredibly fecund and adaptable red maple swept into the available ecological spaces.

Will other tree species succeed the red maple? Will northern red oaks, sugar maples, or American beeches (all slow growing but very shade tolerant species) become established in the understories of the red maples and eventually grow into the canopy? Or will the red maples maintain their dominance via their staggering numbers and ecological tenacity? Check back in hundred years or so to see!

 

 

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Signs of Spring 8: Red Maples (part 1)

Photo by D. Sillman

Photo by D. Sillman

There is a trail that Deborah and I have hiked many times over the years. We call it the “Up and Over,” and it runs up the north side ridge of the Kiski River and then down into the ravine of Roaring Run Creek. It is a very seldom walked trail although there are a few mountain biking paths that get some activity especially on nice, sunny weekend days. A great thing about hiking familiar trails is that you have a mental map of all of the nice spots where you can take short rests along the way. One of these places on the Up and Over is a sitting log under a large red maple way up on the crest of the Kiski Ridge. When you sit on the log (munching some favorite snack and having a cool drink from your water bottle) you look down over the Kiskiminetas River which runs fast and shallow over its red-brown, silt covered rocks and out across the tree covered framing hillsides and the distant ridges. Deborah’s picture above shows the scene from this spot in early April (next week I’ll show you what it looks like a month later!).

I remember sitting in this spot a couple of years ago in the third week of March before any of the trees had leafed out. It was a sunny day but damp and cold. There were even a few lingering patches of snow on the north-facing slopes and in some of the more shaded hollows.

Red Maple flower Public Domain

Red Maple flower Public Domain

About a third of the trees had a fuzzy, reddish glow around their sun-lit branches. These were the first flowering trees of the season and quite obviously from this high vantage point the single most abundant type of tree throughout this river valley. These gently glowing, red flowering trees were red maples.

The other common names of red maple describe important aspects of its ecology and uses. “Swamp maple” and “water maple” tell us that this species is a tree of wet soils. “Soft maple” indicates that the wood is easily worked (and maybe not as strong as the wood of some other types of trees), and “scarlet maple” is a name for those who maybe crave more elegant adjectives!    The presence of red maple all along the river and up the creek-cut hollows made sense relative to the tree’s ecological names, but the abundance of the tree along both the north-facing and south-facing ridges doesn’t seem to fit. Red maples were everywhere. Why?

Through the twentieth century, the red maple became one of the most widespread and abundant trees in eastern North America. In the pre-settlement forest, red maple was found in the places described by its many common names. It was a relatively minor tree of the overall forest and was concentrated in wet, poorly drained sites. How and why did this species proliferate so greatly? How and why did it spread over most of the available landscape?

Looking around from my sitting log I see red maples of all sizes and ages. Thousands of tiny seedlings fill up the spaces around the larger trees, hundreds of its thin saplings rise several feet up above them, and dozens of its skinny “pole” trees in turn rise up over them. This is a red maple forest in a robust state of reproduction. Again the question, “why red maple?”

One of the reasons that explain the “why and how” of red maples is the tree’s great ability to make seed. Flowering and seed production can begin in a red maple as young as four years of age. Young trees that are two to eight inches in diameter can make tens of thousands of seeds each year. Older trees that are a foot or more in diameter can make a million seeds in a single year. Bumper crops of seeds are produced every other year, but every year is a good seed year for red maples.

Photo by Dcrjsr, Wikimedia Commons

Photo by Dcrjsr, Wikimedia Commons

The seeds mature in double, winged samara and are shed from the parental tree in late spring. There are very few germination requirements for the red maple seeds. They can germinate in the shade under the parental tree, or in the direct sun many hundreds of yards away. They can germinate in very wet conditions or in very dry conditions. They can germinate on piles of leaf litter, on bare mineral soil, in cracks in sidewalks and driveways, in rain gutters, and even under the windshield wiper blades of a 1990 Geo Prism (personal observation). Ninety percent of the seeds produced can germinate and they are able to do so almost immediately after flying away from the parental tree.

The small seeds in their samaras can fly great distances in a strong wind. Any area with red maple trees will fill up with red maple seeds and seedlings, and this system saturation will be renewed each year! Most of the first year seedlings will not survive, but since there are so many of them each, and since each passing year adds countless more to the population, in a short period of time the forest understory will be full of red maples.

What is the nature of the competition and stress matrix affecting a red maple seedling?  First of all, there are the thousands of other red maple seedlings. For an individual seedling to prevail its genetic make-up and physiological potential must match up with the restrictions and factors of its environment.  Many studies have described the broad genetic range of red maple populations: different genetic types are found (and, therefore, have succeeded) in wet lowlands and in dry ridge ecosystems. Root growth patterns in these extreme sites are different (deep roots are favored in dry sites but shallow, spreading roots are favored in wet). Secondly, the seedling’s energy potentials must match the restrictions of its site. If it is in the deep shade of a closed canopy forest, the seedling must be able to live at low photosynthetic activity (and comparably low respiratory and growth activity) for many years. If the seedling is out in the full sun, it must be able to handle the large energy input of the full sun exposure and the potentially dry conditions that full sunlight exposure might generate.

(Next week: deer and red maples, a complex symbiosis!)

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Signs of Spring 7: Multiflora Rose

Photo by D. Sillman

Photo by D. Sillman

The color green is returning to our winter gray-brown ecosystems. The grass in our yards is starting to grow at an interestingly uneven rate. In my own yard places where Izzy has “visited” over the winter seem to be greening up faster and growing more robustly than the place not graced with her “presence (or should I say “presents?”). Lawns are looking shaggy all up and down my street, and they are getting more and more unkempt (or should I say more and more natural?) with each passing day. Some of my neighbors have been out mowing three or four times this season. The sound of their riding mowers roaring past my open windows with their distinctive Doppler whines makes me miss winter and its glorious quiet! Lawn grass that doesn’t look like carpet, for some people, is absolutely intolerable, but the energy and resources that our society pours into lawn care is obscene!

But don’t get me started on lawns!

Photo by D. Sillman

Photo by D. Sillman

The woods are greening, too, but much of this is actually not a welcome sign of spring. The first green in the understory of the forests around here is almost all due to the early leafing out of one particularly, noxious,  invasive plant: multiflora rose.

Multiflora rose (Rosa multiflora) is an introduced plant species that is native to Japan, Korea, and Eastern China. It was first brought to the United States in the 1860’s for use as root stock for ornamental roses. It was subsequently used as a “living fence” plant, as highway buffer vegetation, and in a variety of disturbed land reclamation programs. Soon, though, the invasive and destructive potential of this plant was recognized. Most states have placed multiflora rose on the “noxious weed” or “banned invasive” lists and are not only preventing its sale and planting and also actively attempting to extirpate it from areas in which has become established.

Multiflora rose can be found throughout the United States except for the Rocky Mountain region, the extreme desert southwest, and most of the state of Florida. It grows rapidly in fields, pastures, roadsides, and sun-lit edges and spaces of a forest. It is especially common in forest sun gaps that are generated by fallen trees. Its rapid growth and tendency to form dense, monocultural thickets allows it to out-compete and over-shade most native plants.

Photo by J. Mayer flickr

Photo by J. Mayer flickr

Multiflora rose is a perennial that grows in long (up to 15 feet), arching, thorny stems that are called “canes.” It has compound leaves that usually are divided into 7 to 9 serratedly edged leaflets. The leaves arise alternately on the long canes. Flowers (which form in May or June) are pink or white and very fragrant. They are pollinated by a diverse array of hymenopterans. A pollinated flower will eventually form a small, leathery, red fruit around a single, hard seed. This fruit is called a “hip,” and hips may persist on the

Photo by Vllseskoser flickr

Photo by Vllseskoser flickr

plant through the next winter and, possibly, for several years. Hips are consumed by a wide array of birds (including American robins, cedar waxwings, and northern cardinals). Passage of the seed through the digestive tract of a bird significantly increases the likelihood of the seed’s germination. Birds, then, represent significant ecological symbionts for the multiflora rose by accomplishing both seed dispersal and scarification.

In addition to developing from seed, multiflora rose is also capable of rooting from the tips of its arching canes. New canes grow up and over older canes, then, and form an expanding, dense mass of heavily thorned stems. These thickets allow very little other vegetative growth within them and, thus, represent an ecological disaster for native plant species. These thickets, though, do represent a highly protective microhabitat for many small mammals (like cottontail rabbits and woodchucks) and birds (including bobwhite quail, pheasants, and many small song birds).

Multiflora rose is one of the first plants to leaf out in the early spring. This early start on photosynthesis gives the plant an energetic advantage over its many potential competitors. The shade generated by the its leaves also acts to inhibit the growth and survival of many other spring plants. This is the time of year to look our across our wooded valleys or up and over our forested ridges to get an appreciation of just how much multiflora rose there is in our ecosystems! The early green we see is almost all this invasive plant species (along with some similarly invasive honeysuckles!), and it is shading and crowding out a huge number of our diverse, native plant species!

Photo by D. Sillman

Photo by D. Sillman

I have a large multiflora thicket at the bottom of my grassy field. I remember consciously avoiding mowing a spindly little rose cane that was growing out in the field about 25 years ago. I subsequently jogged my mower around the larger and larger and more and more highly branched rose bush, then rose patch, then rose thicket over the coming years. I don’t remember what I was thinking when I let that tiny plant live, but it is now a building sized, dome-shaped mass of heavily thorned, intertwined canes that serves as a roosting habitat for cardinals, a protective cover for a large woodchuck and a couple of rabbits, and black hole that has captured (and kept!) numerous soccer balls, Frisbees, and baseballs. It has also served as a seedling nursery for two mulberry trees that now stretched out over the thicket. These trees are covered with fruit in June and are a favorite feeding and gathering spot for flocks of American robins and cedar waxwings!

No other plants, though, grow under these rose canes. Carefully pushing the thorny canes aside all you see is bare soil without even a hint of the grasses and weeds that were there when the rose cane got started. The rose thicket is making some ecological contributions to my yard and field ecosystem, but it is also taking an awful lot of resources in return!

 

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Signs of Spring 6: What’s Living in Your Home?

Photo by CGP Grey, Wikimedia Commons

Photo by CGP Grey, Wikimedia Commons

Looking around the inside of your home is a very comfortable way to do some complex observations of nature. A house is a habitat not only for humans and their acknowledged cohabitating species (a wide range of mammal, reptile, bird, and fish pets) but also for many vertebrate and invertebrate species that find the non-stressful conditions of the inside of a house (not to mention the rich food sources and great nooks and crannies for reproduction and hibernation!) incredibly agreeable!

But, I don’t want to talk about the occasional raccoon that wanders into your garage or basement or the odd black snake that slithers in from the deck. We have all had birds and squirrels and bats in our attics, and I have even heard of deer pushing open screen doors and walking into living rooms and kitchens.

None of these species really “lived” in your house. They probably were frantic to get out once they realized that there were humans (probably screaming humans) way too close at hand!

Anyway, there was a research paper published in January in the journal PeerJ that looked at some more persistent fellow-occupants of our homes: the arthropods!

Mathew Bertone of North Carolina State University and his research team sampled for arthropods in fifty homes near Raleigh, North Carolina. They collected more than 10,000 specimens (on average 200 per house!) and found 34 taxonomic orders and 304 taxonomic families of arthropods. They very conservatively estimated the total number of species collected from the fifty houses at 579. On average each house sampled had 62 arthropods families and 93 species. A number of these species (149 to be exact) were quite rare and, as Bertone commented in an interview with The Atlantic magazine, “I encountered organisms I’ve never seen before as an entomologist collecting for 15 years in North Carolina.”

American cockroach, Photo by Sputniktilt, Wikimedia Commons

American cockroach, Photo by Sputniktilt, Wikimedia Commons

Most of these arthropods were not pest species. Cockroaches for example were only found in 6% of the houses, fleas were only found in 10%, and bed bugs (Cimex lectularius) were not found in any of the houses.

Species from twelve arthropod families were found in at least 80% of homes. These included “cobweb spiders” (family Theridiidae) that were found in 100% of the houses sampled , carpet beetles (family Dermestidae) also found in 100% of the houses, and gall midges (Cecidomyiidae) and ants (Formicidae) also found in 100% of the houses. There were also book lice (Liposcelididae) in 98% of the houses, dark-winged fungus gnats (Sciaridae) in 96% of the houses, “cellar” spiders (Pholcidae) in 84% of the houses, weevils (Curculionidae) in 82% of the houses, mosquitoes (Culicidae) in 82%, scuttle flies, (Phoridae) in 82%, leafhoppers (Cicadellidae), and non-biting midges (Chironomidae) in 80% of the houses. Dust mites (Dermatophagoides sp. (Pyroglyphidae)).were found in 76% of the homes sampled and significantly more mites were collected from houses that had carpeted surfaces than those that had hard surfaces (e.g., wood floors).

Common House Fly, Photo by USDA Wikimedia Commons

Common House Fly, Photo by USDA Wikimedia Commons

Four groups of arthropods dominate the average room sampled in this study: flies (23% of collected species), beetles (19%), spiders (16%) and hymenoptera (predominantly ants)(15%). Overall, there are more types of flies associated with human homes than any other group of animals. Book lice were the most ubiquitous indoor arthropod (found in 49 of 50 houses). Book lice are close relatives of the parasitic lice that have a long evolutionary history of living, among other places, in close association with birds, mammals and their nests (including those of primates).

Carpet beetle larva, Photo by A. Karwath Wikimedia Commons

Carpet beetle larva, Photo by A. Karwath Wikimedia Commons

Pest species that were collected, though, were quite typical of the same pest arthropods that have been detected in ancient archeological ruins! In other words, these species have been with us for a very long period of time! These pest species included grain weevils (Curculionidae), carpet beetles (Dermestidae), grain beetles (Silvanidae), cigarette and drugstore beetles (Anobiidae), house flies (Muscidae) and lesser house flies (Fanniidae)

Photo by D. Sillman

Photo by D. Sillman

This paper inspired me to do a visual arthropod scan of the rooms in my house. In the window frames of my workroom I found overwintering house flies, two very inactive earwigs, and several hibernating brown marmorated stink bugs. Up in the corners of several of the upstairs rooms I saw a number of small “cobweb” spiders and in the silk of their webs there were a number of small gnat-like flies well wrapped in spider silk awaiting their eventual ends. I have in the past found dust mites in the debris in the furnace ducts, but every other year cleaning of these ducts has greatly reduced this population (and my allergies, too!). Out on the glassed in porch I found overwintering lady bird beetles hiding under the aluminum

S. Williams, Flickr

S. Williams, Flickr

siding, and some more stink bugs under the carpet and in the drawers of a storage cabinet. In the basement I saw a fishing spider, several “cellar spiders,” and two “basement centipedes.” There were also a few drain flies in the basement bathroom and a few more hibernating stink bugs.

So, in a very casual, visual survey I found eleven different arthropods lurking in the corners and crevices of my house. I am far short of the 93 species average in the North Carolina study. If this were summer I know that I would add more flies (especially crane flies and several kinds of mosquito), some beetles, two or three kinds of ants, and probably a couple of kinds of moth or butterfly. Hopefully, there won’t be any fleas this year or ticks (but they almost always show up sometime in the summer!). We have, in fact, throughout the winter found the occasional deer tick on our dog. Dogs and cats are marvelous vehicles for the transport of arthropods into a house!

Finally, just to give you a little more perspective on the numbers of arthropods around us let’s look at some data from the Smithsonian Institution concerning insects (the most abundant and most diverse group of arthropods). According to the Smithsonian there are 10 quintillion (ten to the nineteenth power!!) individual insects alive on Earth at any given moment. That means for each of the 7.4 billion people on Earth there are 1.35 billion insects! Maybe we all need to add some extra rooms onto our houses to make space for all of our friends!

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Signs of Spring 5: Looking out the Window and Walking on Some Trails

Photo by D. Sillman

Photo by D. Sillman

Spring is starting to explode all around us. I have flocks of arriving blackbirds and grackles out under my bird feeders (usually in the afternoon). They chow down on the spilled seed and the leftover deer and squirrel corn and then head off on their way north (or east or west).It is nice to see them, but I hope that they don’t stick around too long. Their noise and aggressive behaviors drive the other birds away from the feeders.

Male cardinals (who have spent the winter very companionably feasting on black oil sunflower seeds together) now are chasing each other around the periphery of the yard. They square off, beak to beak with crests raised and heads slanting forward and low (such attitude!) in attempts to intimidate their opponents and get them to back off and leave the prime breeding spots (and females who are still busily eating their seeds!) to them.

The juncos are still here, so winter has not yet completely disappeared. The red maples are just starting to flower. They are flowering later than most previous years. The big silver maple at the bottom of my field has been in flower for a couple of weeks now. I am starting to feel the tree pollen in my itchy eyes and runny nose.

Photo by D. Sillman

Photo by D. Sillman

Robins have quickly become an expected species out in the field or in the back yard. Their status as harbinger of spring vanished very quickly! They are digging through my leaf piles looking for worms, and singing so beautifully at dusk and at dawn. When I take Izzy for her early morning walk, we are often chorused by a vibrant wall of bird songs. I hear robins, cardinals, titmice, and wrens. The crows and the blue jays add their own rhythms, too.

The scarlet and red oak pole trees all around the yard still have most of last year’s leaves attached to their branches. Passing winds rattle the dry leaves like castanets. Pretty soon the new, emerging leaves will weaken the attachment points of the old sending the old ones tumbling to the ground. Leaf fall as a sign of spring? Sure, why not?

Up at Harrison Hills Park I saw three downy woodpeckers fussing and chasing each other up and around a sugar maple tree. I assume that all three were males contesting the boundaries of their breeding territories. They also had spent the winter in much more social frames of minds and had been parts of the mixed bird flocks (along with chickadees, titmice, nuthatches and creepers) that foraged together for seeds and insect larvae. The female downies are probably still in one of these flocks, but the males have been compelled (ah, hormones!) to go off on their own.

Photo by D. Sillman

Photo by D. Sillman

The bluebirds are back at Harrison Hills, too! We saw two small groups of four male bluebirds also acting very badly toward each other. One of these groups was up around our boxes that line the periphery of the park’s northern meadow. Two the males were actually bouncing between two of our nesting boxes. One male perched on top of the box while the other ducked inside for a quick look around. Then they retired to a nearby tree to chatter and peck at each other. We saw one pair go beak-to-beak and actually crash to the ground in their argument! It was very tiring just watching them expend all of that energy! The female bluebirds will be arriving very soon. By then the males should have their territories all worked out and be ready to puff up, sing and be as impressive as possible!

We checked out the big pond at the south end of the park to see how the beaver is doing. We did not see any new beaver activity. The lodge in the middle of the pond looked unchanged from January. We did see a very handsome pair of mallards, though, swimming around the edges of the pond.

Photo by D. Sillman

Photo by D. Sillman

Walking across the fields at Harrison Hills we also saw colt’s foot flowers and swarms of little wolf spiders (Pardosa spp.) running about on the tops of the dead vegetation. Deborah did a beautiful ecological study of these spiders several years ago. In an old field ecosystem (much like this one up at Harrison Hills) she had found two, almost identical species of Pardosa apparently living together in a shared habitat. This would seem to violate one of those fundamental laws of ecology called the Competitive Exclusion Principle which simply states that no two species can occupy the same niche in the same ecosystem!   What Deborah did was then sample for the spiders first during the day and then during the night. She found that one species of Pardosa was active during daylight hours and the other was active at night! Niche separation! No violation of Competitive Exclusion and a very neat research project and paper!

Photo by D. Sillman

Photo by D. Sillman

Skunk cabbage is still in flower in most of wet areas of the park. It is just starting to send up its first green shoots and will soon fill in these low areas with its heavy, broad leaves.

Over Spring Break we flew out to New Mexico and enjoyed a jump start on the early to late spring transition. Flowers were blooming all over Albuquerque and trees (cottonwoods, willows, redbuds) were in early leaf (such beautiful light green shades!) or flower. The Sandhill cranes had departed just the week before we got there, but we saw flocks of robins (all in the city itself, none out in the surrounding desert), some really impressive raptors (Coopers hawks, Harriers, and kestrels). We even saw (while we were touring an animal rehab “zoo”) flocks of ravens (who perched on the tops of the cages of the captive birds (hawks, owls, caracaras, and, yes, even a raven) probably harassing them mercilessly (except at feeding time when the tables were turned!). We also saw a wild roadrunner scooting along the dirt path in between the cages of the peregrine falcons and the barn owl!

It was amazing walking on paths with a full sun beating down on our heads feeling a dry, wonderful 80 degrees! Our sinuses actually cleared out and I could feel my vitamin D levels returning to normal!

We are in typical March cycle of weather right now. One day is warm and sunny and the next is cloudy and cold. Rain and snow are in the long-term forecast. Summer is coming!

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Signs of Spring 4: Updates on Bats and Bees

USFWS, Wikimedia Commons

USFWS, Wikimedia Commons

My bat house came down this past December along with the wind broken spruce tree to which it was attached. I had put the bat house up back in 2010 in hopes of sheltering some little brown bats (Myotis lucifugus) and to try to help make a contribution in their recovery from the decimating impacts of white nose syndrome. No bats ever came to live in my bat house, though, and the house is now in my garage waiting to be repainted and, hopefully, reattached to some tree that will be noticed by some homeless little brown bats!

In summers past I would sit out on my deck in the early evening and watch a busy swarm of bats (mostly little browns) flying circles and crossing patterns in the fading light of the early night sky. Last summer, though, I would see, at most, one or two bats a night (each of whom was flying around my bat house tree with no recognition of its wonderful aspect (facing the rising morning sun) or its very high quality of construction!).

There was a report on the Penn State News website this past winter (December 4, 2015) that updated the bat population census from the Shaver Creek Environmental Center over near State College. In 2007 (the year coincidentally that the white nose fungus infection was first reported in hibernating North American bat colonies) 1400 little brown bats were in residence at Shaver Creek. Every night in the summer a crowd of observers gathered at dusk to watch clouds of bats emerge out into darkening night sky. This past year there were only 2 little brown bats at Shaver Creek. White nose syndrome and the immense winter die-off that it triggers was the cause of this staggering decline in these important animals.

Photo by A. Valentine, Flickr

Photo by A. Valentine, Flickr

A single bat will eat between three hundred to three thousand insects a night. A million bats, according to the Wisconsin Bat Monitoring Program, eat six hundred and ninety-four tons of insects a year! That’s a lot of mosquitoes and potential crop pests! It has been estimated that a farmer in our bat-deprived world will have to spend between four and five thousand dollars a year on pesticides just to achieve the insect pest control that the bats had provided for free.

Bats reproduce very slowly. A female can have only one pup per year, so the time frame for the recovery of the little brown bat population is going to be incredibly long, and this recovery will only occur if the winter die offs from the white nose fungus infections stops; a very big (and very uncertain) “if.”

There is a very recent piece of good news about bats and their response to the fungus that causes white nose syndrome. A paper published on March 9 in the Proceedings of the Royal Society B clearly demonstrated that Chinese bat species are resistant to these fungal infections, and the authors’ speculate that this resistance is genetic! If white nose syndrome’s spread can be slowed down, then, the hope is that Natural Selection for these similar genes in North American bat populations might result in fungal resistant bat populations here.

Last winter (January 23, 2015 “Signs of Winter 8”) I wrote about the winter survival strategies of a number of species of North American bees. For the sake of time and space several additional bee species missed the cut, so to speak, and their descriptions had to be edited out of the final essay. In order to start my bee discussion here on a positive note, I wanted to include a short description of a little known bee species that many keen bee observers find quite interesting: the mason bee.

Photo by B. Moisset, Wikimedia Commons

Photo by B. Moisset, Wikimedia Commons

Mason bees (Osmia spp.) are very short-lived (only six weeks or so), solitary bees. These bees nest in tubes or holes and have earned the name “mason” because of their tendency to build wall-like partitions made of mud inside of their tubular nests. A mason bee will gather pollen and nectar from the flowers that are blooming during its short life and primarily use its gatherings to pack food around the eggs that it lays in those mud-wall partitions of its nest. A mason bee may fill up more than one nest with its eggs and its accumulated nectar and pollen. The eggs then hatch into larvae, feed on the stored food and steadily grow and develop. The walls are extremely important here because they keep each larvae isolated with their own food supply! The mature larvae then spin a cocoon and develop into pupae which will, still inside the cocoon, then molt into adults. It is inside of this protective and insulating cocoon that the mason bee overwinters. In the spring, the male mason bees emerge first and wait outside of the nest for the later emerging females so that they can mate. After they mate, the males die, and the females then find suitable tubular structures for their nests and begin to lay eggs, gather nectar and pollen, and, as a great ecological tie-in to this activity, pollinate many different species of flowering plants.

So what else have we heard lately about bees?

In a report late this past summer (N. Y. Times, July 23, 2015) 70% of the honey and pollen samples collected from honeybees in Massachusetts contain neonicotinoid insecticide residues. As I reported in the “Signs of Fall 6” (October 1, 2015), a paper published in the April 25, 2015 issue of Nature showed that both honeybees and bumblebees were strongly attracted to flower nectars that contained neonicotinoid pesticides. These pesticides are commonly used for insect control on crops but have been linked to significant bee damage in many studies (The European Union has banned these pesticides 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). This unexpected affinity of bees to these chemicals may explain why they are so toxic to these important pollinators.

Argentine ant (Photo by Penarc, Wikimedia Commons

Argentine ant (Photo by Penarc, Wikimedia Commons

In a February 8, 2016 article in the N. Y. Times, it was reported that the Asian virus that causes wing deformities in infected honeybees was being spread not only from honeybee colony to honeybee colony but from continent to continent (Asia to Europe! Europe to North America! Europe to Australia!) primarily by the commercial trading and transporting of honeybee colonies! This virus has raced around the world in a very short time period and can, especially if combined with Varroa mite infestations cause colony collapse disorder. The Times also reported (in a September 11, 2015 article) that Argentine ants (Linepithema humile)(an invasive species ranked among the one hundred worst animal invaders in the world!) can spread these bee wing deforming viruses from honeybee colony to honeybee colony within their considerable invasive ranges (15 countries and 6 continents)! The introduction of a virus infected honeybee colony into an area also infested with Argentine ants seems to guarantee that the virus will be quickly spread to all honeybees in the area.

So, we have short-sighted pest control policies coupled with careless dispersion of infected and invasive species! It’s amazing we have any honeybees left at all!

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Signs of Spring 3: So Many People!

Photo by NASA, Wikimedia Commons

Photo by NASA, Wikimedia Commons

There are, according to the World Population Clock, 7.4 billion people currently living on Earth. Like most very large numbers it is difficult to really appreciate what a term of this magnitude really means, but we can compare it with some other numbers to try to gain some perspective.

For example, when I was born in 1951 there were 2.5 billion people on Earth. Inference: the Earth’s human population has tripled during my lifetime! LOTS of people have been added to our Earth in the past 60-some years!

Also, if we think about humans living not on the supportive crests of all of our technologies but instead existing as just another species in the Earth’s natural ecosystems (we would be hunters and gathers and scavengers, and, of course, prey for just about any other predator out there!), then the Earth could probably only support about 3 million humans. Inference: if humans were really and truly part of Nature, 99.96% of us who are alive right now would not (and could not) exist!.

All of this, of course, leads me to think about Agriculture!

Photo by J. Atherton, Flickr

Photo by J. Atherton, Flickr

I was reading a chapter in John Reader’s book Africa: Biography of the Continent in which he discusses the “invention” of agriculture. According to Reader, the first evidence that humans had learned how to control the growth and productivity of wild plant species comes from a site in the the Klasies River Caves in South Africa that is dated back to about 70,000 years ago. Abundant residues of starchy plant roots have been found on stone tools and relics on this site, and via a long chain of logic and inference researchers have concluded that these early humans controlled and cultivated crops of widely dispersed plants (probably through controlled burning) and augmented their hunter/gatherer lifestyle menu with a rich and predictable source of carbohydrates. This cultivation, though, was interrupted by some unknown set of events, and this first agricultural technology was abandoned. Apparently, this cycle of temporary adoption of plant cultivation followed by a return to the old ways of existence was repeated many times over many millennia by people in Africa and Asia.

Public Domain, Wikimedia Commons

Public Domain, Wikimedia Commons

About 12,000 years ago, though, armed with domesticated plants and animals gathered from the Middle East, Anatolia (“Turkey”), and the Nile Valley agriculture took hold and became the primary system by which humans fed themselves. The success of this continually evolving system of controlled food production can be read in the stunning growth of the human population on Earth (data from Goldwijk and van Drecht (2007)): in 10,000 BC there were 2 to 4 million people on Earth, but by 1000 AD there were 295 million people! By 1850 there were 1.26 billion people, by 1951 (already mentioned above) there were 2.5 billion people. Now there are 7.4 billion of us! The exponential nature of this population growth curve is breathtaking and it was fueled in large part by the growth and change in agriculture!

Humans have existed as a species (Homo sapiens) for about 200,000 years. Over 190.000 years of this time span the limits of the natural carrying capacities of the Earth’s ecosystems have kept the number of humans at or often well below the 3 million mark. Agriculture, which celebrates its 12,000 year birthday, oh, let’s say next Tuesday, has allowed our numbers to soar!

The path, though, through our 200,000 years of existence has not been smooth. Geneticists looking at patterns of human DNA infer at least two evolutionary “bottlenecks” (severe population declines) in the history of our species. Li and Durban (2011) describe some of this data in their paper in Nature. One population decline occurred just before or possibly just as the genus Homo came into existence about 3 million years ago. The population of the “humans-to-be” was winnowed down to just 10,000 individuals all packed in to a small area in Africa! Possibly this restriction of the “humans-to-be’s” genome assisted the emergence of the intelligent, and extremely adaptable Homo line of species!

Later, when Homo sapiens began to spread out of Africa into Europe and Asia, the second bottleneck occurred. This was between 20,000 and 40,000 years ago and it involved the number of humans on Earth declining to possibly just 1200 individuals in Europe and Asia and just 5700 individuals in Africa. Again, this bottleneck may be one of the reasons that explain why human beings (all 7.4 billion of us!) are so similar to each other genetically!

All of which gets us to a video made by writers at New Science who posed the question “what if humans didn’t exist?” These two past bottlenecks suggest that this contemplation of a world without us may not be too great of a stretch of the fabric of science!

What if an environmental crisis wiped out Homo sapiens early in our existence as a species? What if the eruption of some immense volcanoes rapidly and radically transformed the climate of the Earth and caused a mass extinction of Late Permian proportions (90% of all species on Earth went extinct)? What if an asteroid crashed into the Earth and vaporized the young savannas of Africa where our incipient species was trying to eke out a living? This asteroid strike might resemble the extraterrestrial impact event of the Late Cretaceous that drove the dinosaurs (among others) into extinction.

What would Earth be like if Homo sapiens were not here?

M. Anton, Wikimedia Commons

M. Anton, Wikimedia Commons

There would be no cities, no large herds and flocks of domesticated animals, and no vast fields of managed agricultural ecosystems. There would be oceans full of fish, large herds of large mammals on the extensive temperate and tropical grasslands (along with some equally large predators). Mastodons, giant ground sloths, large toothed cats, not to mention bison would occupy North America and would have to deal with those annoying, sky-filling clouds of passenger pigeons (and more!) in their daily existences.

There would be no rising levels of atmospheric carbon dioxide (because there would have been no Industrial Revolution and no fossil fuel burning binges). There would be no accelerated Greenhouse Effect. Maybe, then, it would time for another Ice Age to start up! (Earth is, in a geological time sense, long overdue for another round of continental glaciers!).

J. Gurche, Wikimedia Commons

J. Gurche, Wikimedia Commons

But maybe, the evolutionary drive toward intelligence is too strong to be thwarted by just a single extinction. Maybe other species, maybe other Homo species (let’s not forget about the Neanderthals!) would have been favored by the elimination of Homo sapiens. Maybe if left on their own, they would have developed agriculture, and science, and had a space program and maybe even more! Maybe, the folks at New Science speculate, the Earth would look a lot like it does now even if Homo sapiens hadn’t been around to alter it!

I am not sure if that is an optimistic or a pessimistic point of view!

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Signs of Spring 2: The Urban Forest

Photo by NASA Earth Observatory, Flickr

Photo by NASA Earth Observatory, Flickr

In Bill Bryson’s wonderful book, A Walk in The Woods, he marvels at the large percentage of the American landmass that is still in (or has returned to) forest. The World Bank sets this percentage (as of 2012) at 33.32%, and this percentage is steadily increasing. This one third of our countryside that is covered with trees is, indeed, an incredible resource and refuge not only for people but also for a myriad of plant and animal species.

But Bryson, though, misses the mark a bit when he talks about these forested lands and their potential impacts on people. Very few people actually live in these forested places and, sadly, even fewer people will actually make the effort to go out and experience them. A 2015 U.S. Census Bureau report states that 62.7% of the U.S. population lives in cities (or other incorporated areas). These cities make up 3.5% of the American land area and are recognizable even from images taken from space. These urban areas are typically places of very little tree cover. Cities, by and large, are the opposite of forests!

It is the task of city planners and managers to make a city as livable as possible for its human residents. This involves creating and maintaining a complex matrix of housing, transportation, resource delivery and waste removal systems robust enough to sustain the densely packed, city-dwelling population, and when you build streets, and houses, and buildings, and sewers, and lay water and gas pipes, and put up electric lines, you also often have to remove most of the existing trees. This generates the “un-forest” appearance of many urban areas.

OLYMPUS DIGITAL CAMERA

Photo by D. Sillman

Increasingly, though, city managers are recognizing the role of trees in making urban environments more conducive to healthy and sustainable human living. For example, trees help to reduce air temperatures by both blocking sunlight and also by transpiring water from their leaves (an evaporative cooling system similar to your body’s use of perspiration to cool your skin’s surface). A single tree can cool air to a comparable degree as ten, room-sized air conditioners running twenty hours a day! These cooling impacts can reduce energy consumption in the summer and also mitigate dangerous summertime “urban heat island” (UHI) effects. Researchers have documented direct connections between UHI’s event peaks and human related debilities, illnesses and even fatalities. Heat stroke, heat exhaustion, heat cramps, and aggravation of heart diseases are just a short list of these UHI impacts on people. Further, the elevated temperature of the lower atmosphere over a city can lead to the accelerated production of ozone and smog with concomitant increases in respiratory disorders and diseases including asthma (see http://www.urbanheatislands.com/ for more details).

A very nice tie-in, by the way, to planting deciduous trees in urban areas is that the cooling impacts describe above will only occur in the summer when the trees have leaves! In the winter, the bare tree branches will generate only very slight shade profiles thus allowing incoming sunlight to warm houses and buildings during the day.

What else do trees do? Trees block the wind and reduce noise and glare. They trap dust and pollen and help to both reduce the high velocity impact of raindrops on soil (a major erosive force!) and absorb surface runoff of rainstorms. One tree can make enough oxygen to supply the daily needs of four people. One tree can also store 13 tons of carbon (from carbon dioxide) per year. (Please see the Tree Vitalize Brochure (http://www.treevitalize.net/) and the North Carolina State Co-op Extension web page (https://www.ncsu.edu/project/treesofstrength/benefits.htm) from which many of these statistics have been drawn)

Photo by D. Sillman

Photo by D. Sillman

Planting trees in our cities, then, is a demonstrably good idea. Human health (both physical and psychological) is improved, energy consumption is reduced, and (and for many this is the big hook for this tree sales pitch) property values go up when you plant trees!

Tree Vitalize (whose brochure I mentioned previously) is a public-private partnership sponsored by the Pennsylvania Department of Conservation and Natural Resources (DCNR), It was established in 2004 with the mission of establishing (or restoring) tree cover in the cities of Pennsylvania. In the first eleven years of this program over five million dollars of DCNR grants along with over six million dollars of matching funds were awarded to groups across Pennsylvania! These funds were used to train over six thousand volunteers and resulted in the planting of almost a half a million trees!

Photo by D. Sillman

Photo by D. Sillman

Locally, in nearby New Kensington, Jane Glenn and the New Kensington Shade Tree Commission have secured Tree Vitalize funds to do three tree plantings along its downtown streets and out in some of its neighborhoods. In these three events (September 2014, May 2015, and November 2015) thirty-seven new trees have been successfully established! I have had the pleasure of participating in these plantings along with an energetic group of my biology students from Penn State. These trees represent a lasting legacy and a bond between our campus and the surrounding community! (This picture of four of these Penn State biology students (Aubrey, Brittany, Jason, and Alaina) standing next to one of their trees is also out on page 15 of the Tree Vitalize Brochure!) The good news is that ALL of the trees that we have planted are thriving!

One last note about cities and trees: as I was looking through some web sites about relative tree cover in large U.S. cities, I was very pleased to note that Pittsburgh ranks at the top of a large city list when it comes to tree cover. New York City, Philadelphia, Detroit and Baltimore each had tree cover percentages in the 20%’s, and Washington, D.C. had a tree cover percentage of 36%. Pittsburgh, though, topped the list with a tree cover percentage of 42% (and growing!). Not bad for a “steel” city!

Think Spring!

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Signs of Spring 1: The Sights and Smells of Spring!

Carolina wren (photo by D.Pancomo, Wikimedia Commons)

Carolina wren
(photo by D.Pancomo, Wikimedia Commons)

I stepped out onto our deck a few days ago and stood, in the lee of the house, and in the high sun of noon, without a coat on, watching and listening for signs of spring. They were all around!

Our Carolina wrens (who have been singing off and on all winter) were now in full voice. The male wren who “owns” my back yard was up in the red maple tree rolling out his “weedeater-weedeater-weedeater-weet!” chorus. A very exciting new wrinkle to this song, though, was an answering call from one of the mulberry trees at the bottom of the field. Another male Carolina wren was either debating the borderline between his lower field territory and first wren’s backyard space, or maybe he was challenging the first male’s entire concept of ownership! The backyard male has had quite a time over the years hanging onto mates (just last year another male swept in and stole off his partner in the middle of the summer!) but the edges of his territory have always been secure! Maybe this is the start of his retirement?

High up in one of the black locust trees two crows were making grinding, croaking calls at each other. They bobbed their heads and clattered away. Their black feathers must have been soaking in the heat of the sun. It had been months since they had felt this warm!
One crocus has pushed its still folded yellow flower up out of the soil in front flowerbed. Everything else is still underground and still. A few more sunny days, though, and the soil surface will be pierced by a whole array of forming flowers.

Photo by D. Sillman

Photo by D. Sillman

The silver maple at the far northwest corner of our field has branches covered with swelling flower buds. The buds are red against the blue sky and seem to get bigger and bigger even in the few minutes you are watching them! This tree is always the first to flower in the spring followed in a week or so by the red maples. The red maple flower buds are still quite small except for the branches that stretch out over the street. The warmth of the heated street surface (or maybe the southerly orientation of these branches?) are driving these buds out ahead of the trees that are scattered out through the more central areas of the yard and field.

Photo by D. Sillman

Photo by D. Sillman

The oaks are still quiet. The younger scarlet and northern red oaks that are steadily replacing the thinning, aging spruce trees have most of last year’s leaves still attached. Watching these leaves finally fall, ironically, will be a true sign of spring!

We went for a walk three weekends ago up at Harrison Hills Park to check on the overwintering bluebird houses and to stretch our winter stiffened legs a bit. Crossing the open fields to reach some of our relocated nesting boxes we walked through a shallow bowl in the terrain. The soil in this depression was extremely wet with accumulated water from the recent snow melt. We sank several inches down into the soft mix of mud and dead surface vegetation. Interestingly the surface of this wet depression was covered with old sugar maple samaras!

Photo by D. Sillman

Photo by D. Sillman

These seeds must have blown into the swale and gotten stuck in the wet way back in the early summer. Why no squirrel, chipmunk or rabbit or bird for that matter had found them and gobbled them up was a mystery to me. This was the only spot where I saw these old maple seeds. If there was no mowing of this field this patch would become a dense copse of sugar maples. On the drier upper sections of the field we saw a few tiny, black Pardosa spiders running about on the dry vegetation.

Photo by D. Sillman

Photo by D. Sillman

We hiked a loop out along the bluffs over the Allegheny River (part of the Rachel Carson Trail) and then cut back on another trail to circle back to the parking area near the Environmental Learning Center where we had parked. We saw no birds, and we didn’t even hear the usual pileated woodpeckers who almost always make themselves known out on these trails by their pounding on the insect-rich black cherry trees. We did see lots of other people enjoying the first mild day in quite a while. Most of them had a dog or two (or three or four!) with them. The dogs were covered in mud and looked as happy as dogs can be! A couple of them deigned to sniff my outstretched hand, but most were so absorbed in the smells and feels of the almost-spring that they couldn’t be bothered with civilities.

Back at the parking lot we had to remove our boots before getting into the car. We put them on top of plastic bags in the trunk and listened to them rolling around on the drive home. We had forgotten about the mud part of spring hiking. Each boot felt a good pound (or more) heavier with accumulated material that had packed its way into its hard waffle-grid sole. I drove home in my stocking feet and had to put off the spring ritual visit to the drive in car wash until I got something on to keep my feet dry.

I guess that this is another sign of spring! A clean car! I got my tennis shoes and drove out to the car wash. It’s amazing! The car is red!

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