Signs of Spring #1: Monarchs Waking up in Michoacán!

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

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

I have wanted to start the Signs of Spring but have not “seen” very many hints that this long, cold winter was ready to give way to warmer, greener days. There are a few birds singing when I take my dog, Izzy, out for her 6:45 am walk. Titmice are pinging out their two note patterns, Carolina wrens (who have sung all winter!) cycle through their four phrase whistles, and northern cardinals make starts at their pulsating, territorial songs from the tops of the surrounding spruce and maple trees. These birds are already thinking about mating. What could be a bigger sign of spring? The blue jays are also pinging and screeching at me but they are just demanding their morning piles of peanuts and shelled corn. Another observation of the approaching spring is that it is not pitch dark at 6:45 am. I don’t have to carry a flashlight or risk being blinded by passing cars’ headlights as I walk along the roadside. We have added an hour and forty minutes to our daylight since the winter solstice on December 21. Sunrise is happening 40 minutes earlier than it did during our darkest day. Now, all of this is important, but it doesn’t quite feel like enough to start our observations of spring.

Photo by R. Kumra, Wikimedia Commons

Photo by R. Kumra, Wikimedia Commons

So, instead, I am starting with a thought experiment: I am imagining that I am in the coniferous forests of the mountains in the states of Mexico and Michoacán in south-central Mexico near the town that our good friend and former teaching colleague, Maria Franco, grew up. The branches and the limbs of these tall trees are covered with the orange and black bodies of millions of hibernating monarch butterflies, and right about now these butterflies are starting to wake up! Great clouds of monarchs are swirling around in the air!

The monarchs that have been sleeping away the winter in these Mexican forests are nearing the end of their nine month long life spans. They are starting to fly to the north drinking nectar from the early blooming flowers and mating along the way. They may get as far as Texas or Oklahoma where, hopefully, their arrival will coincide with the emergence of this season’s milkweed plants. The females will then lay their three to four hundred eggs on the milkweeds (spreading the eggs out over a large number of plants) and the overwintering generation will die.

The eggs will hatch in three to five days depending on the temperature. The emerging larvae feed first on the egg capsule and then begin to eat the milkweed leaves. They will molt five times during this larval life stage and increase their body mass more than two thousand times. The eggs and the larvae (the “caterpillars”) are under intense predation and parasite pressures. More than ninety percent of the eggs and caterpillars will fail to survive. Eggs will be eaten by ants, earwigs and snails, and larvae will be eaten by beetles and other insects (like paper wasps) or killed by parasitoid wasps, bacteria, or fungi. Since the larvae feed exclusively on milkweed leaves they accumulate the milkweed’s cardeolides (a cardiac glycoside that can cause the heart of a vertebrate to stop its contractions!) in their body tissues. These cardeolides make the larvae (and, eventually, the adults) poisonous to most vertebrates. Relatively few monarch caterpillars or adult butterflies, then, will be consumed by vertebrate predators.

Photo by T. Hall, Flickr

Photo by T. Hall, Flickr

The end stage caterpillar then forms a cocoon (“chrysalis”) within which the tissues and organs of the larvae dissolve and are reformed into the structures of the butterfly. This metamorphosis takes between nine and fifteen days. The emergence of the butterfly from the chrysalis stimulates mating and a drive to fly on toward the northeast. New adults repeat this mating, feeding, and egg laying cycle several times through the summer until seasonal conditions or some innate developmental cue triggers the adults to turn around, forgo mating, and then start the long trip back to the mountain forests of Mexico.

The above cycle is characteristic of the very large monarch population that is east of the Rocky Mountains. Almost all of these butterflies overwinter in the coniferous forests in the mountains of Michoacán and Mexico. This round trip migration to and from this very specific overwintering site in Mexico covers several thousand miles. The monarchs that live in the smaller area west of the Rockies, on the other hand, overwinter in in coastal sites in Southern and Central California. Their migratory route only measures hundreds of miles at the most. In both overwintering sites, however, the numbers of monarchs covering the trees and shrubs while they wait out the winter months in their inactive, diapause states can be truly staggering!

There are some recent observations about the long-distant, migrating, eastern monarchs. One involves the impact of the long, fall migration to reduce the parasite load of the butterflies’ population. A serious, protozoan parasite (Ophryocystis elektroscirrha) that infects monarchs is eliminated when they undergo the strenuous migration all the way to the forests of Michoacán (because infected individuals do not survive the migration!). When the monarchs bypass the long migration (by selecting to overwinter in forests of southern United States (like in Barbara Kingsolver’s excellent novel “Flight Behavior”)) or when they linger too long at planted patches of tropical milkweed (which does not undergo a seasonal die-back like the temperate milkweed species), then they do not select out individuals carrying the parasites possibly with disastrous results (results that could include annihilation of the entire overwintering population!).

The trip to Mexico, then, is built into the health and fitness of the entire monarch species! Maria has promised Deborah and I that she will take us to Mexico to see the monarchs in their forests. A great January trip that will feel like a dream!

So, on this cold, wintery day I am not looking at the ice and snow around me. I close my eyes and I am in Michoacán with the monarchs. It is a glorious sign of spring!

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Signs of Winter 12: Blight Resistant American Chestnut Trees! (go, Stumpies!!!)

Forest History Society

Forest History Society

Last week I wrote about the emerald ash borer and its devastating assault on our eastern forests. In that essay I mentioned the America chestnut and the terrible blight that attacked it over one hundred years ago. American chestnuts were once one of the most abundant trees in the eastern United States. They were not the tallest tree in the forest, but they did have huge trunks that could be ten or twelve feet in diameter and thick, extending, shading branches that spread out over remarkably large areas (Photo of virgin American chestnut trees used with permission from the Forest History Society).

The American chestnut (Castanea dentata) also produced large numbers of extremely palatable nuts that were eaten not only by squirrels, birds, deer, and bears but also humans. The American chestnut made these nuts in abundance every year (unlike oak trees, say, that make their acorns over multi-year, boom and bust cycles). Many animals relied on the yearly production of chestnuts to sustain their populations.

Photo by B. Marlin, Wikimedia Commons

Photo by B. Marlin, Wikimedia Commons

In 1904, though, the American chestnuts lining the roads and walkways of the Bronx Zoo began to sicken. Their leaves withered and great lesions appeared in their bark. The trees then died one by one. They were the first recorded casualties of Chestnut Blight epidemic that swept through the eastern United States. There is evidence that the fungus responsible for this disease (Cryphonectria parasitica) had been present in the southern U.S. since the 1820’s, but the death of the chestnuts in New York set off alarms that reverberated through the country. By 1950, the American chestnut was for all intents and purposes “gone.” It was no longer a reliable source of nuts or timber. It was no longer a tree of size and majesty.

The species, though, persisted even in the face of this awful disease. The fungus can be transported either via insects or on the wind and infects a tree through cracks in its bark. The fungal mycelia then grow into the cambium layer of the tree (the part of the tree that includes the vascular system that transports sugars and nutrients). The tree responds to the infection by sealing off the infected cambium with a dense, callus tissue. But the fungus grows faster than the callus and eventually the tree loses its ability to transport nutrients and dies. The fungus, though, does not affect the tree’s roots, and new chestnut trees are then able to sprout from the still living roots and stumps. Depending upon the site density of the chestnut trees and the abundance of the fungal spores, these new sprouts may grow for ten to fifteen years before the fungal infection kills them. They can reach heights of fifteen to twenty feet and can even produce nuts for several years before they die back. This growth and die-back cycle has caused the American chestnut to become more of a shrub than a tree!

All this, though, might be changing dramatically. Two researchers (Bill Powell and Chuck Maynard) and their teams at one of Deborah’s and my alma maters, the State University of New York College of Environmental Science and Forestry (SUNY-ESF) (a college whose students are affectionately referred to as “Stumpies!”) have unveiled a viable and thriving, transgenetic American chestnut that is resistant to the fungus that causes chestnut blight. They are waiting for final federal review and approval so that they can begin planting these trees back into the forests of the eastern United States.

Photo by J. Grandmont, Wikimedia Commons

Photo by J. Grandmont, Wikimedia Commons

How they developed this hybrid tree is simple to explain but astoundingly complex in its actual accomplishment. Some forty years ago researchers at another institution noted that strains of pathogenic tree fungi that produce low levels of oxalic acid are far less virulent than the strains that produce high levels of this acid. So the researcher team at SUNY-ESF isolated a gene from wheat plants that codes for an enzyme (oxalate oxidase) that breaks down oxalic acid and inserted it into the genome of the American chestnut tree. It turns out that wheat and many other grass species use this oxalate oxidase as a generalized protection against their own fungal infections, and it further turns out that this enzyme is equally as effective as a fungal control agent in the transgenetic chestnut tree! The chestnut blight fungus makes large amounts of oxalic acid at the margins of those calluses (or “cankers”) that the chestnut trees make to try to seal the fungal infection off from the tree’s healthy tissues. The acid eats away the wall of the protective callus and allows the fungus to then run riot through the tree’s tissues. Breaking down the oxalic acid at this margin not only neutralizes the erosive tool of the fungus but also, via the impact of the hydrogen peroxide that is being generated as a consequence of the catalyzed oxalic acid oxidation, strengthens the lignins in the wood of the callus! The callus, then, very effectively seals off the blight fungus and the tree remains healthy!

The Chinese chestnut tree and other Asian varieties are resistant to the chestnut blight fungus through other genetic mechanisms, but it turns out that the transgenetic American chestnut with its oxalic oxidase enzyme and lignin enhanced calluses is even more resistant to the fungus than those Asian chestnut species to this disease!
The final phase of this SUNY-ESF project is to raise and plant ten thousand of these blight resistant, transgenetic American chestnut trees. This past fall, to raise funds for this effort, the Development Office of SUNY-ESF set up a crowd funding campaign called the “Ten Thousand Chestnut Challenge.” They sent emails to SUNY-ESF alumnae and to past donors to the college hoping to raise the fifty thousand dollars needed to cover the costs of this tree production program. In the four brief weeks of the campaign, they exceeded their goals and raised over one hundred and four thousand dollars!

Photo by N. Tonelli, Flickr

Photo by N. Tonelli, Flickr

A benefit of becoming a contributor to this chestnut tree crowd funding challenge was that you received a small bag of American chestnut tree seeds as a token of thanks. These seeds are not for the transgenetic, blight resistant American chestnut, but instead are from a genetically diverse array of wild American chestnut trees. The trees grown from these seeds will serve as “Mother” trees that will be crossed with the transgenetic chestnuts to greatly expand their genetic base! My zip-lock bag of chestnut seeds are in the salad crisper of my refrigerator getting their three months of “winter weather” so that they will germinate when planted in the spring. I will share pictures this summer!!

If you want to read more about this fantastic research and rehabilitation effort, check out www.esf.edu/chestnut . Happy winter, everyone, and happy chestnut forests!

Go, Stumpies!!

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Signs of Winter #11: Winter Walk on the Nature Trail

Photo by D. Sillman

Photo by D. Sillman

Last week Deborah and I finished our Friday classes and office hours by noon and then planned to spend a couple of hours out on the campus Nature Trail. It was still quite cold (about 20 degrees) with a strong wind between 15 and 20 mph. After we got back from the hike, I entered the temperature and wind speed data into an on-line wind chill calculator and came up with a 4 degree F wind chill. We were a bit more sheltered from the wind down in the woods, but now I know why our hands and feet felt so numb!

There was a light, cloud cover (what we call “Pennsylvania sunshine”) so we headed out with our camera to try to re-take some of the pictures that have illustrated our winter hike on the Virtual Nature since 2001. The sunlight, though, failed us and the pictures turned out too dark to use on the web site.

To get to the entrance of the Nature Trail we had to cross the new soccer practice field. The snow on the field was about ten inches deep, well packed down by freeze-thaw cycles, and covered with a hard, thick, icy crust. Each step we took broke through the ice and sunk our boots a couple inches down into the Styrofoam-like snow. The noise of each of these steps was an impressive set of crashes and crunches. The two of us sounded like an army marching down a gravel road.

Photo by D. Sillman

Photo by D. Sillman

We wanted to watch and listen for birds along the trail, so we had to stop frequently to get relief from the walking noises to try to catch hints of the bird songs around us. By the time we got to the trail I realized that my binoculars were safe and warm back on my desk in my office. Oh, well. We did see and hear chickadees and titmice in the low branches around us and spotted a solitary, white-breasted nuthatch high up in the branches of a sugar maple tree. There were also some small groups of sparrows flitting around in the low undergrowth, but without binoculars I couldn’t tell if they were white-throated sparrows or song sparrows. We also heard the faint rappings of woodpeckers (downies?) back in the woods far off of the trail. We saw a lot of evidence of woodpecker activity, too (more on that later).

The snow on the trail was as crusted and as deep as it had been out on the soccer field, so walking was difficult. The snow surface in the woods was also covered with rabbit tracks! In the winter the eastern cottontail forages around looking for woody plants to consume (including the twigs, bark, and buds of oak, dogwood, sumac, maple and birch). Usually these rabbits hunt for food by themselves in the winter, but the density and pattern of the tracks made it look like a good sized group of rabbits had been collectively active out on the trail in some kind of a rabbit rumpus! It looks like we have a robust population of eastern cottontails this year!

Our boot crunching scared up a white-tailed deer (a doe) that had been hunkered down in the brush of the oak and poplar section of the trail. She leaped on ahead and was down the slope of the ravine before we could even point the camera in her direction.

Up The Poplar Tree!  Photo by D. Sillman

Up The Poplar Tree!
Photo by D. Sillman

I had descriptions of the web site photographs we were trying to upgrade, and it was very interesting looking at the trail from a “year 2001” perspective. For example, we wanted some shots of wild raspberry canes sticking up through the snow and of barberry bushes with their little red berries still attached, but these plants were not as abundant as they had been fourteen years ago. Instead, almost all of the plants growing along the trail were multiflora rose! This invasive plant, which I have written about many times before, apparently, has outgrown and out competed the native raspberry and also the exotic barberry and has greatly changed the floral composition along the trail.

Several trees have come down across the trail this winter. A white ash has fallen across the Entrance Trail, a yellow poplar is blocking the end of the Red Pine Trail, and a tall, sugar maple has fallen across the Wildflower Trail. The size of the maple forced us to detour high up into the woods as we were hiking on the blocked trail up from the bridge over the lower stream. Clean-up Day this spring will require a chain saw or two to clear the paths.

Photo by D. Sillman

Photo by D. Sillman

The most significant thing we saw on this snow hike, though, was up beside the pavilion at the beginning of the trail. Along the Entrance Trail are a number of white ash trees. These trees are interesting for a number of reasons including the rich growth of lichens that cover their ridged, diamond-patterned bark. Students in past years have mapped these lichens and evaluated the preference of the lichens for the complex surfaces of these trees. Today, however, the bark of all of the white ash trees along the trail were scratched and scarred with woodpecker holes. The woodpeckers (probably the downy or the hairy from the relatively small sizes of the bark tears) were in search of larvae of beetles living just beneath the bark. It was an ominous sign. It indicated that these white ash trees were infested with emerald ash borers.

The emerald ash borer (Agrilus planipennis) is an exotic invasive beetle from Asia (eastern Russia, northern China, Korea and Japan). It was first detected in the United States in 2002 in a stand of ash trees near Detroit, Michigan, but it has probably been in North America since the 1990’s. The beetle has subsequently spread to twenty-four states and two Canadian provinces. There are 7.5 billion ash trees in the United States and nearly all of them (green ash, black ash, white ash, and blue ash) are threatened by this beetle. So far, 50 million ash trees in the United States have been killed by the emerald ash borer.

The adult, ash borer beetle is quite striking in appearance: it is about a half and inch long and is a bright, metallic green. Adult females lay eggs on the ridged bark of ash trees and the hatching larvae then eat their way through the tough outer bark into the living tissues of the tree. The phloem (the sugar/sap transporting vascular tissue) and the actively growing, cambium layer of the tree are consumed by the developing larvae. The larvae can so effectively destroy the sap flow of the tree that entire limbs or even the main trunk of the tree can be effectively “girdled” (or severed) thus causing limb systems or the entire tree to die.

In June 2007 the emerald ash borer was found in Cranberry Township in Butler County just to the west of Penn State New Kensington. In June 2009 it was found in Westmoreland County (the county where our campus is located) in nearby Allegheny Township. Now we know that it is here in Upper Burrell Township, too. To date, fifty-five counties in Pennsylvania have been infested by the emerald ash borer.

Sadly, these white ash trees will die. There are white ash trees all across the long ridge on which Penn State New Kensington sits and many more down in the wooded valleys that surround us. These trees are also probably infested and are dying.

Think of the carnage that has hit our forests because of exotic, pest species! The impact of the emerald ash borer may remove an entire group of tree species from our eastern forests. It may be even more devastating than the Chestnut Blight or Dutch Elm disease, two other exotic, invasive diseases brought to North America by human activity. And, remember the gypsy moth and their devastation of our oak trees? There is a large, fallen white oak out on the campus nature trail that is testament to the gypsy moth population explosions of the 1990’s! And, let’s not forget about the Asian long horned beetles that are plaguing our maples and many other hardwood species or the wooly adelgids that are destroying our state tree, the Canadian hemlock. And, most sadly, there are many more! Our forests have been and continue to be under terrible assaults by agents we have transported from afar.

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Signs of Winter 10: Cardinals! (and some House Cat Day Results!)

Photo by D. Sillman

Photo by D. Sillman

Back in early December in response to the Signs of Winter #4 blog about northern juncos, Irene Wolf, a teaching colleague at Penn State, asked about the cardinals she was seeing in Cheswick. It was hard to believe, she wrote, that these beautiful birds were hardy enough to survive our harsh winters. Could they be some other species?
Nope. They are cardinals!

The northern cardinal (Cardinalis cardinalis) is one of the most recognizable birds in North America. The bright red body feathers and distinctive black mask of the male and the more subdued but equally elegant olive brown and red-tinted feathers of the females stand out clearly in their wide range of preferred habitats. They are very abundant in the edges of woods and thickets, in open fields, in suburban yards and gardens, and in a wide variety of urban green spaces.

The northern cardinal is found throughout the eastern United States and on south into Mexico and Central America. Historically, cardinals were most numerous in the southern portions of their geographic range, but they have been steadily increasing in numbers in the north and are even expanding their distribution northward into northern New England and southern Canada. The western boundary of their range is roughly along a line from the Dakotas to western Texas although there are cardinal populations in New Mexico, southern Arizona, and California. There are cardinals in northwestern Iowa. I remember my Uncle Harold talking about how much he liked “those red birds” that visited his farm out in Humboldt County. I remember standing out in his yard watching small groups of bright red cardinals mixed in with large flocks of cedar waxwings.

Photo by K. Thomas, Wikimedia Commons

Photo by K. Thomas, Wikimedia Commons

The expanding distribution of the northern cardinal has been described by some as another ecological consequence of global warming. Some researchers, though, feel that the increasing popular hobby of providing birds with seed in feeders may have allowed this species to thrive in regions previously too marginal or too harsh for their survival. Further, the ongoing fragmentation of natural forest habitats by human activity and the proliferation of suburban shrub and conifer plantings have created increasingly abundant “edge” ecosystems which are greatly favored by this species.

The northern cardinal eats a wide variety of seeds (including those from pine trees, smartweed, blindweed, foxtail, dock, thistle, chickweed, button weed, sorrel, and a great variety of grasses), fruits (including grapes, dogwood fruit, blackberries, cherries, and raspberries), and even the buds of some trees (including elm and chokecherry). They also eat insects and, in fact, rely almost exclusively on insects as food for their rapidly growing young.

Cardinals are also very common visitors to backyard bird feeders and avidly consume large quantities of sunflower seeds. In fact, if you put a bird feeder with a bird seed mix that does not include sunflower seeds, you are very likely to not attract very many cardinals! The northern cardinal is not migratory and will remain even in the most stressful parts of its geographic range throughout the winter if it is sustained by human-maintained bird feeders.

Our front yard bird feeders are visited by an abundant number of cardinals throughout the year. In the spring males perch on top of the tallest trees around the edges of the yard and sing their pulsing, territory songs. Mated pairs frequently have three clutches of eggs and can be seen throughout the summer frantically feeding their fledglings on every surrounding branch and fence post. The nurturing compulsion of this species is legendary. Someone once even observed a compulsive parental cardinal trying to feed seeds to surface gaping goldfish in a garden fish pond!

Photo by N. Townsend, Flickr

Photo by N. Townsend, Flickr

The arbor vitae on the west side of our property, and the spruces and hemlocks on the north and west boundaries are full of cardinal nests throughout the summer and are packed with night roosting individuals throughout the winter. In the winter we often have twenty or thirty cardinal at a time swarming the perches of the front yard seed hoppers and the piles of spilled seed on the ground below them. The red males light up the gray days and stand out electrically against the brown leaves and the scattered, white snow.

Northern cardinals are preyed upon by owls, small hawks, and house cats. I frequently find bright red feathers in piles below perches used by our pair of sharp-shinned hawks. My cats (which whom I just celebrated our third annual House Cat Day on February 2!) are both too fat and too addicted to crunchy, dry cat food to pay much attention to quick moving birds! Cardinal nests may be raided by chipmunks, blue jays, crows, and a variety of snakes. Two summers ago I described a cardinal nest built out in a spruce tree just outside my back window that was raided and destroyed by cows and blue jays. Also, cowbirds are common nest parasites, and northern cardinals complete with catbirds and mockingbirds for nesting sites.

Photo by M. Hamilton

Photo by M. Hamilton

On average, northern cardinals live for 3 years in the wild although several individuals have had life spans of 13 to 15 years. The longevity record for a captive northern cardinal is 28 ½ years! It is nice to think that the cardinals we watch each winter and summer will be around with us for several years to come!

House Cat Day results varied across the country. In the warm, sunny southwest (Albuquerque, NM) my daughter

Photo by D. Sillman

Photo by D. Sillman

Marian’s cats (Binx and Mora pictured above) spent their House Cat Day lounging outside on a picnic table, seeing their shadows, but not reacting to them in any way at all. Analysis: an early spring in New Mexico.

In Apollo, Pennsylvania Mazie went out (on February 3 because of very lousy weather on the 2nd!) and immediately ran for the open porch door. Analysis: six more weeks of winter for us!

 

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Signs of Winter 9: House Cat Day III

Photo by D. Sillman

Photo by D. Sillman

Two years ago in my January 21, 2013 blog (very optimistically entitled “Signs of Spring 3”) and again in last years’ January 28, 2014 blog “The Winter: Housecat Day II” 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, but rather on 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 robins, or bumblebees, or scarlet tanagers as our symbolic animal to celebrate the anticipation of the coming spring, but settled on what was, to me anyway, the most logical 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). Housecats, usually, share the warm, dry living spaces of a house with humans (of course, they usually keep the really nice spots all to themselves!), and cats especially share with humans a hardwired, probably DNA-based fondness for sunshine, warm temperatures, and fun, fluttery organisms like birds (their “bird-agenda,” though, is often quite different from ours!).

Photo by D. Sillman

Photo by D. Sillman

So, two years ago on February 2, I took one of my housecats, Mazie (pictured above), out into the snow-covered front yard (I tried to take both of my cats, but Taz (pictured to the side) 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 Mazie stayed on her towel or starting 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 by late February. 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.

Last year I did the same, and Mazie responded with equal speed and agility and got back into the house even before Deborah could take the lens cap off of her camera. Last year, though, winter hung on grimly well into March. Mazie’s prediction, then, fit the observed phenomenon. The model has re-set itself?

Photo by M. Hamilton

Photo by M. Hamilton

We’ll find out on Monday, February 2 what this year will bring! Mazie returns to the front yard for her third experimental trial. If I can find Taz I will take her outside, too! Deborah will have her camera all ready before the test begins! I am sure that Mazie will do her best for us all! Our daughter Marian has her two cats (Binx and Mora (pictured to the side)) primed and ready for a New Mexican House Cat Day celebration! The Tradition is spreading! Blog followers in Washington, in Illinois, in Iowa, in California, in New York, and in Oklahoma, if you don’t have a cat of your own, borrow one! Dare to participate!! Results will be published soon!

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Signs of Winter 8: Bees!

Photo by I.Tsukuba, Flickr

Photo by I.Tsukuba, Flickr

Jennifer Wood and her husband Robert Steffes keep bees. Over the years they have been not only great sources of information about these wonderful animals, but also they have kept me well supplied with the jars of honey I need to get my blood sugar elevated enough each morning to face the new day!

Jennifer responded to the “Migrate, Mutate, or Die” blog (Signs of Winter #5) by describing the adaptive strategies their bees (European honeybees, Apis melifera) employ to survive the winter. European honeybees do not hibernate, but instead stay active throughout the long, cold winter months. The honeybees cluster around the honey combs inside of their hives and shiver their flight muscles to generate heat. The temperature inside of a bee-warmed hive can reach as high as ninety degrees F (although optimal temperatures would not be nearly that warm!). The cluster of shivering bees moves up (never down!) the honey comb so that they continually encounter fresh honey to fuel their muscle contractions and heat production. These bees also rotate individuals from the very warm middle of the shivering cluster to the less warm, more stressful outer edges in order to spread the impact of the winter’s thermal stress over the entire group.

Photo Public Domain, Pixabay

Photo Public Domain, Pixabay

European honeybees, then, are primed and ready for the first hints of spring weather and are able to move right into pollen and nectar gathering as soon as temperatures and the first waves of spring flowers allow. This ability to immediately respond to the bounty of spring is a significant selective advantage for the species.

There is a downside to this overwintering strategy, though. Two years ago I wrote about the impact of a warm, late winter on honeybees that triggered their early emergence into a world in which no plants had yet flowered. These bees spent a large amount of their limited energy reserves in futile attempts to find nectar and ended up gathering almost anything that might substitute for their natural foods (one gentleman in Latrobe wrote me about bees completely cleaning out his cracked corn bird feeder!). Without extra feeding by a beekeeper, these bees would be very likely not to have sufficient food to survive the remaining cold days and nights of the winter and early spring.

The overwintering strategy of the honeybee, then, sits in a very delicate balance between great success and absolute failure! The European honeybee, though is only one type of bee out the twenty thousand known species, and many of these other types of bees have very different “solutions” to surviving the winter,

I went to a web site that listed the common insects of Pennsylvania (insectIdentification.org ) and noted the types of bees likely to be present here. The site listed the European honeybee, four species of bumble bees (Bombus spp.), and two species of carpenter bees (Xylocopa spp).

Photo by P. Vivero, Wikimedia Commons

Photo by P. Vivero, Wikimedia Commons

Bumble bees, like European honeybees, live in colonies. The sizes of these colonies, though, are quite different. A domesticated honeybee colony can contain up to eighty thousand individual bees during the peak of summer activity. A bumble bee colony, though, usually has less than fifty individuals. Toward the end of the summer new queens (fertile female bees) and fertile male bees mature in the bumble bee colony. These fertile individuals emerge and mate, and then the males die shortly thereafter. The mated queens, though, continue to feed on flower nectar and pollen and find crevices, holes, or even sheltering flowers in which they can spend the night. They steadily build up considerable body energy reserves that will see them through the long winter.

Eventually, as the summer fades and the cooler nights of autumn signal the coming winter, these queens find more protected places (often abandoned mouse nests or burrows in sandy soils) where they can hibernate. They go into a physiological state that enables them to slowly use their energy stores as they wait out the long, cold winter months. Early in the spring, these queens stir from hibernation and begin to forage for nectar and pollen among the early spring flowers. Their large body sizes and extensive coverings of hairs enable them to retain heat even in air temperatures that would seem to be too cool for insect activity. In the early spring these great, floating bees fly about close to the soil surface in their search for flowers. They must be careful, though, not to misjudge their rate of energy use or the lateness of the day or they might get caught out away from their hibernaculae and end up freezing in the cold, night air.

These bumble bee queens eventually establish their summer colony site and begin to lay eggs. The small cohort of workers that develop, then begin to assist the nurturing and survival of the colony. A bumble bee colony only lasts one season, so it is imperative that enough food resources be gathered to fuel the production of the next generation of queens.

Photo by ysmad.com, Wikimedia Commons

Photo by ysmad.com, Wikimedia Commons

Carpenter bees (Xylocopa spp.) are solitary bees (they do not form colonies although in some species the sisters and/or the daughters of a fertile female may continue to nest together in a simple social group). Adult carpenter bees drill branching cavities into wood (and can be the cause of a great deal of damage to buildings and homes), but they do not eat the wood. They discard the woody debris (or use it to make partitions inside of their woody nest) and rely on nectar and pollen for their food. Carpenter bees are important flower pollinators and many people have made the decision that the wood damage they cause to homes or barns is small price to pay for all of the essential pollinating work these bees accomplish.

Photo by ZooFari, Wikimedia Commons

Photo by ZooFari, Wikimedia Commons

Adult carpenter bees hibernate in the woody burrows in which they were born and in the spring, emerge and mate and either continue to live in those nests with their extended female family members or strike off and establish new woody burrows nearby. The male carpenter bees live solitary lives outside the nests and visit flowers to gather their individual food requirements. They do not, however, enter the nests at night or contribute to the groups’ accumulation of pollen or nectar.

Bees, then, survive winter in a variety of ways. They can be adults shivering together, waiting for warming temperatures. They can be mated, hibernating queens sleeping through the snow and cold. They can also be un-mated males and queens hibernating in their parental nest burrows.

I can’t wait to see the spring bumble bees drifting about like little zeppelins or the swarms of honeybees clustering over the first flowers of the spring! We have more winter to get through first, though! Hang in there!

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Signs of Winter 7: Beavers and Otters

Photo by Steve, Wikimedia Commons

Photo by Steve, Wikimedia Commons

Over the past few weeks I have had two very interesting communications from friends and colleagues here in Western Pennsylvania. One involved signs of beaver activity along the Kiski River and the other involved seeing river otters in one of the ponds at Harrison Hills Park.

The beaver report was from Carl Meyerhuber who, up until this extreme cold spell anyway, has been braving the winter weather each afternoon to do his two mile walk on the Roaring Run Trail along the north bank of the Kiski River. Carl has been seeing gnawed tree trunks and piles of chisel-shaped wood chips at spots along the trail, sure signs that the Kiski beavers are out and about.

Beavers (Castor candenesis) were once a very common component of the fauna of not only Western Pennsylvania but almost all of North America. These large, semi-aquatic rodents once had a continental population of sixty to ninety million individuals. They were, however, of great economic value to Europeans moving across the continent (and some say they were one of the main reasons that the Europeans moved across North America as quickly as they did!). By the end of the Nineteenth Century, there were only a fraction of the original continental population still alive, and there were no beavers at all remaining in Pennsylvania.

Conservation programs were established in Pennsylvania to try to re-establish beaver populations. In 1917 a pair of beavers from Wisconsin was released in the state, and between 1918 and 1925 one hundred more were brought in and released into our waterways. By 1934 the beaver populations had grown sufficiently that a regulated trapping season was established.

Photo by Hugo.arg, Wikimedia Commons

Photo by Hugo.arg, Wikimedia Commons

Beavers instinctively build dams with the small trees and branches that they cut with their powerful front incisors. They carry and float these building materials to constricted points along small streams and then mud-cement into place across the water flow. These dams create protective ponds within which the beavers can build their lodges. Lodge construction, though, seems to be a learned behavior. The “island-type” lodges set in the middle of a protective pond may have a variety of geometries

Photo by R. Stevens, cynic.org.uk

Photo by R. Stevens, cynic.org.uk

and styles but all have a number of underwater entrances and exits and at least two inner chambers (one for drying off after returning from a swim, and the other for sleeping and rearing their young).

Beavers may also build their lodges onto and into the banks of larger rivers. These “bank beavers” are the same species as the island-lodge beavers but adapt themselves to a landscape in which flat, slow flowing streams suitable for damming are not available. These river bank lodges are also constructed of mud-cemented sticks and logs, and they also have multiple below water entrances and exits and at least two internal chambers. These lodges may also extend into the soil of the river bank often in and around protective and supportive roots of large river bank trees. Both types of lodges become extremely secure in the winter as the mud holding the sticks and logs together freeze into a nearly impenetrable, concrete-like mass.

The beavers along the Kiski are “bank beavers.” The steep hillsides coming down to the river do not provide sufficiently flat expanses for beaver dams to generate protective ponds. When you drift down the Kiski in a canoe (an activity that should wait for MUCH warmer weather!) you can see these beaver lodges tucked into river bank. If you happen to be out near sunset, you may even glimpse one of the beavers as they start into their nocturnal foraging for building supplies and food.

Beavers preferentially eat water plants when they are available but survive on the inner bark of a variety of trees especially through the winter. They cache large quantities of sticks and branches under their lodges for winter consumption when conditions do not allow them to forage freely about. Poplars and aspens are preferred tree species but maples (especially red maple), birches, willows, cottonwoods, and pines are also consumed. The increased cutting activity that Carl has observed along the Roaring Run Trail is probably due to a stimulated gathering of winter food by our local beavers.

Public Domain, Wikimedia Commons

Public Domain, Wikimedia Commons

There are lots of neat details about beavers! Their front incisors continuously grow! These tree-cutting teeth are harder in the front than they are in the back and, so, wear into a beveled biting instrument that generates the very recognizably shaped wood chips around any beaver tree site. Beavers are the second largest rodent on Earth (exceeded in size only by the capybara of South America). Ten thousand years ago, though, an ancestor species of our North American beaver was the size of a black bear and weighed close

to five hundred pounds!

Photo by  D. Azovitsev, Wikimedia Commons

Photo by D. Azovitsev, Wikimedia Commons

The other semi-aquatic mammal story of the moment was actually mentioned (and pictured!) in the local newspaper a couple of weeks ago. Two river otters (Lutra canadensis) were spotted in one of the ponds up in Harrison Hills Park in northern Allegheny County.

Like the beaver, river otters were once abundant and widely distributed in Pennsylvania. But, also like the beaver, human impacts (through direct hunting and also through indirect destruction of the otters’ habitats through land clearing and stream pollution) greatly reduced the Pennsylvania otter population and functionally extirpated the river otter from almost all of the state’s waterways. In 1982 researchers from the Game Commission and Frostburg University released one hundred and fifty three wild otters that had been captured in Louisiana, Maryland, and New York into nine rivers in Central and Western Pennsylvania. In the intervening thirty-three years these otters have multiplied and spread throughout the watersheds of Pennsylvania.

The otters released into the Allegheny River (one of the nine original release sites) were undoubtedly the stock from which the Harrison Hills otters were derived. It is a very long climb up from the Allegheny to the bluffs on which Harrison Hills park sits, but the promise of fish-rich pond waters must be quite an attraction for these active predators.

In 2006 Deborah and I and Marian and Joe were canoeing on the Youghiogheny River (another release site for the otters) when we spotted an otter swimming and playing among the river rocks. She seemed as interested in us as we were in her, and the few minutes we spent observing each other was the highlight of that glorious river trip.

Beavers, otters, wild turkeys and bald eagles are all symbolic of Pennsylvania ecosystems steadily regaining some of the charismatic fauna that they have lost over centuries of ignorance and misuse. These animals make even simple walks in the woods and quiet floats down a stream potentially so much more exciting and so much more filled with adventure!

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Signs of Winter 6: Birds of a Feather

Photo by Frauke (Pixbay)

Photo by Frauke (Pixbay)

Winter is a great time to observe flocks of birds. Large birds, like geese for example, often fly in specific geometric formations (the “V’s”) in order for individuals in the flock to take advantage of both reduced wind resistance and also the up-wash of air that a front-flying bird generates both behind it and to its sides. Birds flying in a “V” formation beat their wings less often than a bird flying alone and also have lower heart rates. Therefore, they are able to glide more and use substantially less energy to power their flying.

Smaller birds, like blackbirds, starlings, and grackles, do not generate large enough air vortices to assist those other birds flying near them. So, there is no energetic advantage to flying in a “V.” These birds tend to fly in large, shape-changing flocks that can number from many thousands to several million individuals (one winter “blackbird” flock in the Great Dismal Swamp on the Virginia and North Carolina border was estimated to contain fifteen million birds!). Watching these swirling and flowing flocks can be a surreal experience! The coordinated twisting and turning movements that they display suggests an immense, living being rather than simply a mob-like mass.

Photo by Baker (Geograph,org.uk)

Photo by Baker (Geograph,org.uk)

Deborah and I have seen many of these “blackbird” flocks during our commuting drives back and forth from campus and our home. They rise up from corn and soybean fields or out of dense shrub fields or woodlots and move as a undulating mass over the roadways. Our car has been pelted by feces from these birds (the woodlot birds were eating wild grapes!). Thank goodness there have been frequent rain showers to clean off the car!

The emergent patterns of these small bird flock movements are generated by the expression of three very simple rules of dynamics (the work of Craig Reynolds was instrumental in bringing these internal control forces to light (see http://www.red3d.com/cwr/boids/)). The first rule is Separation: each individual in the flock tries to maintain an optimal distance from its neighbors. The second rule is Alignment: each individual steers toward the average direction their neighbor is going. The third rule is Cohesion: each individual tries to maintain a standard density of individuals in space.

These three rules are seen not only in flocks of birds but also in schools of fish, herds of mammals, and even in crowds of people! Complex group movements result as each individual in the group tries to keep their spacing, alignment, and crowd density constant.
Flocks (or schools or herds) may seem to be a huge disadvantage for a prey species seeking not to be noticed by a predator. Any predator could see or hear or smell a flock or a herd of thousands to millions of individuals! There are, though, many consequences of being in a large crowd that might lessen the impact of predation on an individual, and these benefits have undoubtedly been sorted out via natural selection and evolution to generate optimal sizes and timings of formation of these flocks, herds, or schools.

The most obvious benefit is “safety in numbers.” There are many eyes (and noses) “watching” for predators. A group of great size should always have someone watching each point in space around the flock/herd/school. Also, there are so many other individuals around for a potential predator to take! This simple risk reduction by large available numbers of prey of equal or even greater quality may be sufficient to offset the increased risk from excessive visibility . This has been referred to as the “dilution effect” in which risk decreases when it is shared over an increasing number of individuals. The famous William Hamilton (the evolutionary biologist from England and colleague of Richard Dawkins whom I talked about in a previous blog) described this dilution effect back in 1971 and used it to coin the term the “selfish herd.” He noted that the survival of individuals increases when they are in a group even though each member of that group is acting in their own self-interests (and are fervently hoping that the guy next to him becomes the predator’s mid-day snack!).

Photo by diGiusti (Wikimedia Commons)

Photo by diGiusti (Wikimedia Commons)

The flocks (or schools or herds) may also confuse predators via their mass movements or obstruct their access to specific individuals by their spacing and density. Some animals take turns rotating from the edges of their flock/herd/school into the more protected center. Many species also keep the more vulnerable individuals of their group (especially young individuals) inside these protected centers and the larger, more robust adults on the more vulnerable edges.

Predators (like many car drivers weaving around under a large, surging flock of birds) may also be confused and maybe even more than a bit intimidated by a huge, moving mass of even the most potentially vulnerable prey species.

Birds form winter flocks for other reasons, too. Finding food is major task in the winter and being in a large group of fellow food seekers makes the probability of finding food much higher. And, even though whatever food is found is then shared by many “beaks,” the net gain of food opportunities more than offsets the loss due to smaller individual portions!

Photo by Rasmussen (Wikimedia Commons)

Photo by Rasmussen (Wikimedia Commons)

Winter flocks of red-wing blackbirds, brown headed cowbirds, common grackles, and European starlings gather together in huge night roosts. The marshes of the coastal regions of mid-Atlantic states (New Jersey, Delaware, Maryland, Virginia, and North Carolina) have especially large blackbird flocks. These roosts disperse during the day into smaller cohorts that may fly as far as fifty miles seeking food.

These large blackbird flocks are also seen in Kansas shortly after the birds’ breeding season has ended. The flocks steadily increase in size with coming winter and transition from roosting in deciduous trees in the later summer and early fall to coniferous trees in the late fall and winter. They feed in the harvested grain fields of the Kansas plains during the day and hide from the prairie winds and the deep cold in the evergreen branches at night. In March the species separate and mating pairs form to get about the serious work of reproduction.

Looking out my back window, I see the falling snow and a mixed flock of chickadees, titmice, downy woodpeckers, and juncos hopping around the leaf piles and poking into the compost pile. When one finds some food item hidden in the leaf litter several others cluster around him and make short work of whatever it is. They then immediately set off looking for more. The cost of resource sharing is more than offset by the benefit of increased resource discovery. Ah. Winter!

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Signs of Winter 5: Migrate, Mutate, or Die

Photo by D. Sillman

Photo by D. Sillman

I have been searching around a number of “famous quotes” web sites to try to find out who first coined the phrase “migrate, mutate or die.” I wanted to use it in a winter blog with a re-phrasing into “hibernate, migrate, or die,” but even through this quote (sometimes with the added admonition “adapt” in between “mutate” and “die” (which might fit my idea for the winter blog even better!)) is widely known and used in many situations and forms, the exact author is (at least so far to me) not clear.

I remember one of my undergraduate biology professors at Texas Tech saying “migrate, mutate, or die” in his slow, drawn-out, West Texas drawl. He was discussing Natural Selection in kangaroo rats, I think. The gist of the phrase is essential Darwinism, but I cannot find these three words in “Origin of Species” or any other book by Darwin. It would have been very unlikely in any case that he would have used the term “mutate” since the “discovery” of genetics and its fusion with Darwinian selection occurred well after Darwin’s death.

I also remember a story that one of my professors at Ohio State told the small group of graduate students who had been brave enough (or possibly just sufficiently uninformed enough) to take the optional, but very demanding laboratory section that went with a two quarter long, plant physiology course. His story was a great relief from the construction of all of the elaborate apparatuses demanded by the course, and it ended with “migrate, mutate, or die” as its punchline. His story was centered on a historically notable plant ecologist at Ohio State in early Twentieth Century. This individual (whose name I have forgotten (and isn’t that the expected fate of all “famous” plant ecologists?)) took some of his graduate students out botanizing on a walk through a nearby prairie relic not realizing that one of the students the night before had planted an arctic circle tundra species out among the prairie flora. The botanist, seeing the unexpected tundra plant, stopped his on-going identification narrative and bent over to look very closely at the alien species. He pointed a long finger at the plant and said, “Migrate, mutate, or die!” and then continued on his field lecture.

Cruising around on the Internet I find this quote being used to highlight many different kinds of discussions. Real estate selling practices, funeral directors’ education programs, businesses’ competition and communication systems, the National Parks Service, some archeologists, and some on-line gamers have all used this three or four word epigrammatic phrase to focus attention on the need to change with a changing environment or run the risk of some respective professional, virtual, or biological “death.”

One document that included the quote was a transcript from an agricultural education workshop at Ohio State back in 1985. A published comment to the workshop’s keynote address attributed the quote to John Steinbeck in his great novel “The Grapes of Wrath.” That motivated me to re-read “The Grapes of Wrath,” and I can tell you that although the motivation to move or change (or die) was a large part of the novel, nowhere in the book does Steinbeck say “migrate, mutate, or die.”

It’s too great of a quote to not have an author, but whoever first said it is quite hidden!
So, let’s get back to winter and my “hibernate, migrate, adapt or die” and leave the original quote in limbo for now.

Photo by D. Sillman

Photo by D. Sillman

Hibernate: Winter shuts down most species’ food supplies. Many species respond to the anticipation of these months of crushingly limited food resources by gorging themselves on the bounty of the late summer and early fall and then falling into the slow metabolic states of torpor or true hibernation so that they can stretch these stored body resources over all of the months of winter. Bears, chipmunks, woodchucks, box turtles, snakes and many more all utilize this system with great success.

Migrate: I have frequently written about species that migrate. The robins, the grosbeaks, the tanagers, the hummingbirds and many, many more use their stored up body fat from their own summer and fall gorging to undertake long flights to tropical or southern hemispherical habitats. They spend their energy reserves on the chance that food will be waiting for them when they get across the Gulf of Mexico or down to the forests on the slopes of the Andes. Then they make the same bet three months later to cover their return north!

Photo by D. Sillman

Photo by D. Sillman

Adapt: The “adapt” part of this winter epigram really means “tough it out.” Get by on less, drive your body to eat whatever is still available in the frozen landscape, or just burn your fat reserves as slowly as you can hoping that they will keep you from freezing and also last until spring. White-tailed deer “tough it out” like this. They eat whatever they can regardless of its level of nutrition. They stuff their shrunken stomachs with chewed branches and other equally indigestible materials, and slow down their metabolic rates as much as possible to make their reserves last.

Die: The “die” option is realized by many individuals in all three of the above categories. Hibernating animals are vulnerable to predators. They also can use up their own fat reserves and end up frozen in their overwintering dens. Many individuals don’t survive the incredible physical demands of migration. It is estimated that half of the migrants leaving North America in the fall do not return in the spring. And, the species that “tough it out” regularly slip off of the razor’s edge of survival and end up frozen in the snow becoming food for a waiting host of other survivors and “adapters.”

So winter is a harsh time for wild species. I keep my bird feeders full all winter to try to help out, and I seldom chase away the squirrels or even the deer who come by regularly and gorge on the astonishingly expensive bird seed, peanuts, and shelled corn. As I watch them from my fossil fuel heated house with the promise of hot coffee and food anytime I want it (which in the winter is almost all the time!), I ignore the monetary costs and am grateful for the absence of my own ecological payment.

It’s winter!

(And, if anyone knows where “migrate, mutate, adapt or die” comes from, please let me know. I will keep looking, too!)

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Signs of Winter #4: Arrival of the Juncos!

Photo by Ken Thomas Wikimedia Commons

Photo by Ken Thomas Wikimedia Commons

When we think of bird migration we usually focus on those species that arrive here in the spring and then depart from here in the fall. These species are utilizing our rich, productive summers and avoiding our cold, food deprived winters. There is, though, a very interesting bird that arrives in our area in the mid- to late fall, thrives in our winters (often supported by our backyard bird feeders!), and then heads back into its northern breeding habitats in the spring. The bird is, of course, the northern junco.

I saw my first northern junco of the fall on October 30. He was poking around at the spilled sunflower seeds under my feeders and looked very much at home among the chickadees, titmice, cardinals and house finches.

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

The northern junco is five to six and a half inches long and weighs between one half and nine tenths of an ounce. Males are slightly larger than females and are more darkly colored. They have gray hoods and backs, white bellies, and dark tails with distinctive white, lateral tail feathers. They also have short, triangular beaks and dark eyes. Juveniles are brown in color and have finely streaked, white breasts.

Photo by Mdf Wikimedia Commons

Photo by Mdf Wikimedia Commons

Like most sparrows, the northern junco will eat a wide variety of foods. Their beaks are especially well adapted to cracking open even tough seeds (including sunflower seeds at bird feeders and an extensive number of wild plant (“weed”) seeds in their natural habitats). They also readily consume fruit (including wild blue berries, raspberries, and elderberries as they come into season) and many types of arthropods (including caterpillars, ants, flies, spiders, and beetles). They typically feed on the ground and move about both by walking and by hopping (a single hop can cover thirty centimeters). Natural ranges can be quite extensive (a single flock of juncos can feed in an area of ten to twelve acres), while human-modifications of their feeding ranges (i.e. bird feeding stations) can greatly reduce the size of the foraging range and overall rate of movement.

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

Males move into their summer breeding habitats in northern coniferous or mixed hardwood forests before females and mark off their individual breeding territories. A male will sing from the top of a tall tree to claim an area of two to three acres. They then attract the attention of the arriving females by dropping their wings and flaring their tails in order to show off their white, lateral tail feathers. Once a female accepts a male they become quite inseparable and within their territory seldom venture more the fifty feet away from each other.

The female builds the nest all on her own. The nest can be located on the ground or on low, horizontally oriented tree branches. Near human habitations juncos may also build their nests in the crawl spaces underneath buildings, inside the buildings themselves or on window ledges. The nest may be made of a variety of materials. Sometimes it is simply a gathering of pine needles and grass, sometimes it has a foundation of sticks on top of which softer materials are layered. Nests take three to seven days to build and they are seldom re-used.

Northern juncos typically have two clutches of three to five eggs each breeding season although under optimal weather conditions, a third clutch is possible. The first clutch is laid in late spring (mid-April) and the second in mid-summer (mid-July). Eggs are incubated by the female for just under two weeks. Nestlings are actively fed by both parents and are able to fledge after another two weeks or so. Fledglings stay with and are dependent upon the parents for another three weeks. Males are very aggressively territorial during this reproductive period. Both male and female, though, will very vigorously defend their nest and nestlings.

The arrival of the juncos in Western Pennsylvania has both positive and negative implications: a handsome bird has returned to grace our lawns and fields, but now we have to deal with the cold, snowy months of winter!

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