Our Noisy World

I used to fear the wind, especially when it roared on top of Sapsucker Ridge. But ever since Interstate 99 was opened, directly beneath the ridge, the wind has been my friend because it masks the traffic noise.

Heavy traffic on an interstate near Pittsburgh

Heavy traffic on an interstate near Pittsburgh (Photo by Doug Kerr on Flickr, Creative Commons license)

During the winter, without the leaves on the trees to absorb some of the clamor, the interstate traffic is louder than ever. Researchers have found that at least six-tenths of a mile on each side of a road is affected by traffic noise, and a portion of our property is much closer than that.

Many humans are badly affected by continual anthropogenic noise, especially that made by roads, airplanes, and extractive industries such as fracking and mining.

In the last couple decades some researchers worldwide have been studying the effects such noise also has on wildlife, particularly birds. They’ve found that sounds made by vehicles, oil and gas fields, and urban sprawl can change the way animals communicate, mate, and prey on one another.

A white-crowned sparrow in California

A white-crowned sparrow in California (Photo by Mike Baird in Flickr, Creative Commons license)

Back in the 1960s, ornithologist Luis Baptista recorded white-crowned sparrow songs in San Francisco and discovered that they sang in three distinct dialects in different areas of the city. David Luther, a George Mason University biologist, studied the same areas in San Francisco in 2008. The traffic noise was much louder in 2008 than it was when Baptista made his recordings. As a result, the white-crowns had raised the pitch and length of their songs to be heard above the urban din and sang in only one dialect.

Another study, of both chipping sparrows and white-crowned sparrows in 2017, also found that white-crowned sparrows as well as chipping sparrows changed their songs in a noisy environment. Two other studies revealed that song sparrows and red-winged blackbirds did the same.

Luther hypothesizes that, “With our loud noise we might be influencing the very evolution of these birds.”

An eastern bluebird on a birdhouse in North Carolina

An eastern bluebird on a birdhouse in North Carolina (Photo by Ken Thomas in Wikimedia, in the public domain)

Eastern North America has little or no areas that are not affected by roads, and Pennsylvania has more than its share of them. Even a bird species seemingly unperturbed by roads—the eastern bluebird—appears to have problems with anthropogenic noise, according to a study of breeding eastern bluebirds in Williamsburg, Virginia.

The scientists concluded that their “study does provide evidence that bluebird fitness is being compromised at stages between egg hatching and chick fledging,” producing smaller brood sizes and less productivity, and thus “the birds will be particularly sensitive to noise during this (approximately) two-week time period.”

Furthermore, they suggest that managers try to keep favored songbird breeding habitats free from human-caused noise pollution.

Other studies report such effects of noise on wildlife as hearing loss from noise levels 85 decibels or greater, masking so that wildlife can’t hear animal signals, predators, or other environmental cues, increased heart rates and stress levels, and even the abandonment of noisy territories.

Probably the most interesting study of road noise in the United States was conducted by Boise State University ecologist Jesse Barber and his graduate students in a roadless southern Idaho forest which had plentiful food for migrating birds. They created a “phantom” road by blasting national park road noise through speakers during fall migration. Thirty-one per cent of the songbird community avoided the area. Those that remained to feed couldn’t gain weight, probably because they were too busy looking for predators.

Barber also cited a study in 49 places worldwide where bird populations declined within six-tenths of a mile of traffic noise. Birds with low frequency songs, such as mourning doves, avoided roads altogether, since they couldn’t be heard above the hum of traffic.

Compressor stations, such as this one in Milford, PA, bombard surrounding forests with noise

Compressor stations, such as this one in Milford, PA, bombard surrounding forests with noise (Photo by cool revolution in Flickr, Creative Commons license)

But roads aren’t the only noise problem that birds face. Studies in natural gas extraction fields found that compressor noise running 24 hours a day changes both breeding areas for songbirds as well as species’ numbers. Those birds that remain despite the noise may have trouble hearing songs or evaluating possible mates, parents may not hear chick noises or have less chance to forage.

In a study Barber and students did of 31 northern saw-whet owls subjected to recordings of a natural-gas compressor station, he reported that every time he raised the sound level by a decibel, the owls’ hunting success declined by eight per cent. Apparently, this owl species can hear sounds as low as negative 20 decibels while hunting for rodents, and when the researchers raised the volume to 60 decibels, the owls couldn’t catch any prey at all. Since all owl species depend on their ears and their eyes to hunt at night, we can only wonder how many other owl species might be impacted by noise.

A three-year study in the woodlands of northern New Mexico surveyed sites next to natural gas wells with compressors, which they compared to sites next to natural gas wells without compressors. Although they found no difference in the number of birds’ nests in both areas, they did observe 21 species nesting at compressor sites and 32 species nesting at those without compressors. However, nests of 14 species were found only at sites without compressors, yet nests of just three species were located only at compressor sites.

In addition, a common species, the house finch, produced 14% of the nests near compressors whereas more uncommon bird species preferred the gas wells without compressors. A whopping 22 of 23 mourning dove nests were built in the vicinity of gas wells without compressors. Even those species that nested near the compressor sites placed their nests farther away from well pads with compressors than they did on those without.

A western scrub jay found in Santa Fe, New Mexico; as of 2016, known as a Woodhouse’s scrub jay

A western scrub jay found in Santa Fe, New Mexico; as of 2016, known as a Woodhouse’s scrub jay (Photo by Peter Wallack in Wikimedia, Creative Commons license)

Another interesting finding was that predators, such as western scrub-jays, avoided the noisy sites and preyed more heavily on nests in the quiet sites. Possibly they preferred the quiet sites because they couldn’t communicate over the noise of compressors.

The researchers concluded that “species intolerant of noise may suffer from not only exclusion from noisy habitats that might be otherwise suitable but also higher rates of nest predation relative to species inhabiting noisy areas.”

They go on to hypothesize that perhaps anthropogenic noise “may help explain the high degree of success among urban-adapted species [such as house sparrows, European starlings, and American crows, for instance] and the homogenization of avian communities in and around human-altered habitats.”

Still another study compared the nesting success of ovenbirds at compressor sites with those without. Although this study was done in boreal Canada, ovenbirds commonly nest in the forests of Pennsylvania and have always and continue to nest in our Laurel Ridge forest, which, unlike Sapsucker Ridge, overlooks a quiet, farming valley. If they still nest on Sapsucker Ridge, I can’t hear them above interstate noise.

An ovenbird on the ground

An ovenbird on the ground (Photo by Trish Gussler on Flickr, Creative Commons license)

The ovenbird researchers discovered that the birds paired at a rate of 92% in the quiet sites and 77% in the noisy sites, probably because the females could not hear the males’ low-frequency “tea-cher, tea-cher” song as readily in the compressor sites. They add that most bird species in forests have low-frequency songs because they “provide optimal long-distance song transmission range in complex forest structures.”

Because of the steepness of Sapsucker Ridge on the interstate side, I have not been able to record bird species and numbers there during the several bird surveys I do here every year, most notably the Christmas Bird Count in December and the International Migratory Bird Count in May. I know that my own hearing is age-impaired, and I can’t hear birdsongs in the distance as I used to.

Since everyone who engages in various bird surveys depends on hearing bird calls and songs to identify them, ecologists in North Carolina wondered if declines in some breeding birds were due to background noise that interfered with the bird counters’ hearing.

The ecologists targeted a few of those experts who participate in the annual North American Breeding Bird Survey, the primary source for population and range information for over 400 species since 1966, and other experienced birders and played singing bird songs against varying levels of anthropogenic noise. Even a small amount of noise led to a 40% decrease in their ability to identify birds.

I can only imagine how many birds I miss every year.


Every winter my feeder birds are mostly the same, both in species and numbers. But usually there is at least one surprise, even in winters when no northern finch irruptions occur.

A blue jay on a feeder in Montgomery County, PA

A blue jay on a feeder in Montgomery County, PA (Photo by Brian Henderson on Flickr, Creative Commons license)

Last winter was the year of blue jays, often nicknamed “jaybirds” because of their calls.

We live tucked away by ourselves atop a mountain so we’ve never had more than a couple blue jays at our feeders over the 46 years we’ve lived here, and many winters none at all. But beginning in early December last year, blue jays started appearing in greater numbers, just as the cold and snow set in.

On December 16, with the thermometer at three degrees Fahrenheit, I counted 10 blue jays at our feeder area. From then until late January, numbers varied from seven to a high of 11 on January 16 when they blanketed the ground with their electric blue color.

Usually they stayed on the ground to feed, sparring with each other and the gray squirrels while the mourning doves and the smaller songbirds hung out in the periphery or visited the feeders, which, in turn were dominated by a pair of red-bellied woodpeckers.

A blue jay feeding with a red-bellied woodpecker in Danville, PA

A blue jay feeding with a red-bellied woodpecker in Danville, PA (Photo by fishhawk on Flickr, Creative Commons license)

At least some of the blue jays roosted in our Norway spruce grove and sounded their clarion “jay-jay” calls whenever I neared it on my daily walks. In mid-February, when blue jay numbers at the feeders had diminished, I found a trail of plucked blue jay feathers in the grove as well as plenty of “white wash” on the tree branches. I suspected a barred owl had been feasting on the blue jays, but whether it was death, the unseasonable warm weather, or some other reason, I last recorded five blue jays at the feeders on February 20 and then no more.

Despite being common birds that almost anyone can identify, these clever members of the Corvid family are not as easy to study as other corvids, such as American crows, because they are secretive and quiet during the spring and summer when they are courting, mating and raising their families.

But as acorns ripen on oak trees, these forest denizens announce their presence here, picking and eating acorns and beechnuts before they fall to the ground. Last autumn both the red and white oak complexes produced a huge crop of acorns, and no matter where I walked I could hear blue jays.

A blue jay with an acorn

A blue jay with an acorn (Photo by Tom Shockey on Flickr, Creative Commons license)

They also cache acorns to eat in the winter and spring, tucking two to three acorns in their expandable throat and upper esophagus, a fourth one in their mouth and a fifth in their bill and carrying them as far as a mile to cache in more open areas. They do the same with beechnuts.

Writing in The Second Atlas of Breeding Birds in Pennsylvania, Douglas Gross (Game Commission Endangered and Nongame Birds Section supervisor) calls the blue jay the “keystone bird of eastern deciduous and mixed forest of North America because of its habit of caching tree seeds, inadvertently planting deciduous trees, especially oaks and beeches…”

Like most caching birds, blue jays have excellent memories for where they hid their nuts, but a few are always missed. In Blacksburg, Virginia, researcher Susan Darley-Hill found that in 28 days approximately 50 blue jays carried and cached 150,000 acorns, which was 58% of the total nut crop from a mere 11 pin oak trees. Furthermore, they were capable of choosing sound acorns that had not been affected by weevil larvae.

Blue jay close-up with an acorn

Blue jay close-up with an acorn (Photo by Kenneth Cole Schneider on Flickr, Creative Commons license)

With those numbers, I can only imagine how many acorns blue jays transported from our forest last autumn. Still, I wondered if the huge crop of acorns was harvested by our resident blue jays or by those that had migrated from other areas.

Like most aspects of blue jays’ lives, their migration patterns are also puzzling. The northernmost subspecies of blue jays (Cyanocitta cristata bromia, our northern blue jay) lives as far north as Canada in the southern half of Ontario, Quebec, and New Brunswick. Sometimes northern blue jays may migrate south since thousands, moving in flocks from five to 250 birds, have been observed over the Great Lakes, including Lake Erie.

In Pennsylvania hawk watchers on our mountain ridges east of the Allegheny Front have reported migrating blue jays from the third week in August to the second week in November, although the greatest numbers migrate in mid-September to mid-October.

While blue jays winter in every Pennsylvania county, the jays are a mixture of resident and migrant birds. Researchers used to think that young jays were the migrants, but more recent studies show that jays of any age may migrate. Furthermore, it looks as if individual jays decide on a year to year basis whether to stay put or move south. Most likely it relates to either food sources, weather conditions or both.

A blue jay on a nest in Codorus State Park, Hanover, PA

A blue jay on a nest in Codorus State Park, Hanover, PA (Photo by Henry T. McLin on Flickr, Creative Commons license)

During spring in Pennsylvania blue jays migrate north from late April until mid-May. By the fourth of May, our resident blue jay males have already engaged in courtship displays with their monogamous partners, which continue as they select their nest sites and construct their nests. Usually they settle on a tree or bush as high as 25 feet from the ground, preferring an evergreen, but settling for whatever is available. They may even use rural mailboxes or occupy the nests of American robins.

Both sexes build their cup-shaped nest of twigs, small roots, moss, lichens and bark as well as human detritus such as light-colored tissue, cloth, paper, string, and wool. The male feeds the female as she sits on the three to seven bluish or light brown, spotted eggs for 17 to 18 days, beginning in late May in Pennsylvania. Then she broods her young for half their 17 to 21 days in the nest before she joins her mate in finding food for their offspring, although the male continues to provide most of the food.

A juvenile blue jay

A juvenile blue jay (Photo by Carolyn Lehrke on Flickr, Creative Commons license)

After their nestlings fledge, usually by July, the family remains together for another month or two. Then the young are on their own, while their parents sustain their bond for their lifetime.

Blue jays eat a wide variety of material including 22% insects during the breeding season. They are known for “anting,” rubbing ants against their feathers to remove the formic acid, not, as previously believed, to rid themselves of parasites, but so they can eat the ants, according to a recent study which found that 10 ants equals one egg in nutritional value.

Blue jays also consume human-based food—cultivated grains (especially corn) and fruit, bread, and dogfood—in addition to hard mast (43%) except in July and August. Their reputation for eating birds’ eggs and nestlings is highly overrated, and most studies put such food at one to two per cent of their diet if that.

Blue jays have their own predators to guard against. As adults they are the victims of Cooper’s, broad-winged and red-tailed hawks, great horned and barred owls and eastern screech-owls. Gray and fox squirrels kill and eat young fledglings, and nest predators include American and fish crows, squirrels, black rat and northern black racer snakes, raccoons and opossums.

Blue jays are known for their wide variety of calls and use them to mob hawks, large snakes, raccoons, domestic cats, and large owls. The video embedded below illustrates the variety of calls made by blue jays. These “songbirds without a song,” as Donald Kroodsma labeled them in his The Singing Life of Birds, use many sounds. After observing a pair on their nest near his home in Amherst, Massachusetts late in April, he noted that “the jays seem infinitely expressive, capable of transforming the simplest of jay sounds into a diverse array. At one extreme, the harsh ‘jay’ becomes a single, fine pure whistle, often with harmonics. Sometimes only one voice box will be engaged, sometimes two, creating special tonal effects.”

Altogether, in three and a half hours, he heard from those jays and others that visited them, five different ‘jay’ variations, two ‘squeaky-gate’ calls, melodious ‘bell calls’ and from the female on the nest ‘rattle’ calls.

“How little we know about these jays—that’s what my brief experience with them has taught me,” he concluded.

In Pennsylvania, blue jays increased from the first to the second atlasing periods with their highest numbers in Montgomery, Lehigh and Bucks counties in scattered woodlots. Because blue jays are able to adjust to changing land practices and airlift tree seeds to open areas, they will remain valuable “ecosystem engineers,” in the eastern United States by “increasing their caching effort after fires and selecting canopy gaps as cache sites,” according to a Cornell Lab press release of a study entitled “Jays and Crows Act as Ecosystem Engineers.”

Even renowned Philadelphia naturalist William Bartram, back in the early nineteenth century, recognized that blue jays “alone are capable, in a few years’ time, to replant all the cleared land.”


Northern Visitors

Last winter I spent hours in our Norway spruce grove watching red-breasted nuthatches. I first saw them on October 28 when one foraged on a Norway spruce tree trunk while another rushed around on the ground in search of Norway spruce nuts.

A red-breasted nuthatch on a Norway spruce in Pennsylvania

A red-breasted nuthatch on a Norway spruce in Pennsylvania (Photo by fishhawk on Flickr, Creative Commons license)

I had already learned from Doug Gross, Endangered and Non-game Bird Section Supervisor for the Pennsylvania Game Commission, writing in the October edition of PSO Pileated (the newsletter of the Pennsylvania Society for Ornithology), that 2016-17 was a big red-breasted nuthatch irruption year. Their conifer seed sources in the north had been sparse, and they were moving south in large numbers in search of native and non-native conifer seeds, including those of Norway spruce plantations.

Back in the 1990s, before the onslaught of hemlock woolly adelgids, I had often watched wintering red-breasted nuthatches in our eastern hemlocks along our stream, but those trees have been ravaged if not entirely killed by the adelgids. In this decade, wintering red-breasted nuthatches have relocated a mile and a half uphill to our one-acre Norway spruce grove.

After my first sighting of them, I rarely missed either hearing or seeing the red-breasted nuthatches in the grove, sometimes in the company of black-capped chickadees and dark-eyed juncos or sometimes on their own.

A portrait of a red-breasted nuthatch in Chester County, PA

A portrait of a red-breasted nuthatch in Chester County, PA (Photo by Kelly Colgan Azar on Flickr, Creative Commons license)

Then, on November 27, as I sat in the lower section of the spruce grove, my back against a black locust sapling, I spotted a red-breasted nuthatch flying frequently to the forest floor in what looked like nervous haste, poking about on the ground, and then flying up to a spruce trunk. I also heard another calling its nasal, tin-horn-sounding “yenk, yenk” from farther away. The one on the ground continued poking and prodding like a pepped-up robin. Suddenly, it landed on a spruce branch close to the ground, four feet away from me, called loudly, and flew back to where I had originally seen it.

Later, sitting on Alan’s Bench at the upper edge of the grove, I heard several red-breasted nuthatches calling from all directions.

Handsome, beguiling birds with bluish-gray backs and wings, rufous-cinnamon breasts and bellies, black heads, and a broad black line through their eyes with a white line above them, they were once known as Canada nuthatches (Sitta canadensis) or red-bellied nuthatches. They are closely related to the larger, deciduous-forest-dwelling white-breasted nuthatches (Sitta carolinensis). Both species climb up and head-first down tree trunks, probing bark crevices for insects, but white-breasted nuthatches are slower and less trusting than red-breasted nuthatches.

A red-breasted nuthatch probing a dead branch

A red-breasted nuthatch probing a dead branch (Photo by budgora on Flickr, Creative Commons license)

On December 1 I was decked out in orange because of rifle season, and I wondered if the red-breasted nuthatches would notice and shy away from me. As I neared my locust tree back rest in the spruce grove, a red-breasted nuthatch was busy probing in the low, dead branches of the large spruce in front of the locust and paid no attention to my flamboyant presence.

Instead, the bird flew to a nearby large dead spruce snag that had been topped in a storm and was joined by a second nuthatch that flew into the same tree. They kept their distance from one another as they ran along the dead, parallel branches as well as up the old trunk. Although highly aggressive and territorial during their breeding period, those that migrate south in the winter remain in small, stable groups with little or no aggression.

By then I was hooked on these quick, agile little birds, and almost every morning returned to the spruce grove to watch them. Sometimes there was one, sometimes two, and several times three birds. Usually they were scuttling around on the bare ground like gray mice, searching for spruce nuts detached from cone scales.

In Mercer County, PA, a red-breasted nuthatch in a November snow

In Mercer County, PA, a red-breasted nuthatch in a November snow (Photo by Dave Inman on Flickr, Creative Commons license)

But once I saw a pair running about on a thin, fresh layer of snow. Then one snatched a spruce nut, flew low on to a tree trunk, and ate it. Mostly though, on the few days with a snow cover, they were high in the spruce trees, hanging on dangling cones, and extracting the seeds.

One January day it was seven degrees, the ground was bare, and I stood watching as one nuthatch rushed about in search of food. I marveled that its tiny feet and legs could move so quickly in the cold and that these little birds have feathers that kept them warmer than my five layers above and three below. Slowly, my upper body and feet froze as the nuthatch continued its rounds in wide circles about six feet away from my still figure.

Other folks in Pennsylvania were watching red-breasted nuthatches at their feeders. Of the 690 Project FeederWatch participants in our state, nearly half reported at least one red-breasted nuthatch at their feeders, but I never saw one come to our feeders.

A red-breasted nuthatch on a feeder in Montgomery County, PA

A red-breasted nuthatch on a feeder in Montgomery County, PA (Photo by Brian Henderson on Flickr, Creative Commons license)

I had hoped the nuthatches might stay to breed in our spruce grove, but I last heard them in mid-March calling from the spruce treetops. Here in Pennsylvania they are irregular, local breeders mostly in our northern tier, especially in the Poconos. But as the conifer plantations planted by the Civilian Conservation Corps in the 1930s during the Great Depression aged, in the 1960s, red-breasted nuthatches sometimes bred in plantations as far south in the commonwealth as York County on the Maryland border and west to Beaver County near Ohio.

Gene Wilhelm, in the Second Atlas of Breeding Birds in Pennsylvania, writes that “few counties had no records during the second Atlas period,” even though the species is still thinly distributed in the state. Most records are from the northern half of Pennsylvania in coniferous and mixed coniferous and deciduous forests and estimates of their numbers range from 18,000 to 28,000 birds.

According to a field note Wilhelm wrote for PSO Pileated, a pair of red-breasted nuthatches nested in their Butler County black spruce woodlot for three consecutive years (2011-13) and then disappeared until early last fall.

A close encounter with a red-breasted nuthatch

A close encounter with a red-breasted nuthatch (Photo by NechakoRiver on Flickr, Creative Commons license)

That’s when Wilhelm also had close encounters with a pair of red-breasted nuthatches. He was sitting outside writing when “the male bird landed two feet from my mobile TV tray, snatched a stinkbug from our porch screen door, carried it in his bill to a limb of a red maple less than ten feet above my head, ate the bug whole, then repeated the antic 10 times in the next 10 minutes. At that point, the female nuthatch dropped to the ground next to the screen door, and helped herself to the easy meal, too.”

That day they made 21 round trips in half an hour and ate 42 stinkbugs. And they returned for six more afternoons making “at least 89 round trips, ate at least 111 stink bugs, in three hours of hunting,” Wilhelm concluded.

Red-breasted nuthatches migrate through Pennsylvania from the second week in April to the third week in May, but those that stay to breed begin courting as early as March. The male sings his courtship song while turning his back to the female, swaying back and forth like a revolving fan and erecting his crest feathers. The pair also flies together with slowly fluttering wings or long glides.

The nest hole of a red-breasted nuthatch with orange colored resin visible around the entrance

The nest hole of a red-breasted nuthatch with orange colored resin visible around the entrance (Photo by Larry McGahey on Flickr, Creative Commons license)

Both sexes excavate a nest hole 2.5 to 8 inches deep in soft aspens, dead or dead parts of trees. They line their nest with fur, fine feathers, grass, hair and shredded bark. The female lays five to eight whitish, spectacled reddish-brown eggs in May.

The pair also applies sticky conifer resin at the outside and inner walls of the cavity entrance. They bring in resin globules from other conifers in the tips of their bills or on a small piece of bark which they use as a tool to apply the resin. Throughout the 12-day incubation and 18-day nestling periods, they do this as often as five to 10 times a day. It seems to be a deterrent for nest predators, such as house wrens, red squirrels, snakes, weasels and even ants, but the parents are able to avoid the resin by flying directly into and out of the nest hole.

An adult red-breasted nuthatch feeding its fledglings

An adult red-breasted nuthatch feeding its fledglings (Photo by Robin Horn on Flickr, Creative Commons license)

The male feeds the female during her incubation period, both on and off the nest and while she broods the hatchlings. Both parents feed their offspring in the nest and for two weeks or longer after they fledge in late June or early July. The young birds may join their parents in mixed species flocks of resident birds and stay together as a family since they have only one brood a year.

But if it is another irruption year, they may begin heading south as early as the first week in August, although their peak migration period is between the third week in September and third week in November.

Because they irrupt every two to three years, I doubt I will see any in our spruce grove this winter. But I will forever remember the year of 2016-17 as my winter with the red-breasted nuthatches.


Crow Blackbirds

On the last day of October, a flock of blackbirds lands on top of a tree behind me as I sit on Coyote Bench. Later, on the Vernal Pond Bench, I hear and then see an enormous blackbird flock as it alights on nearby oak trees and then erupts overhead in a wheeling flock of several hundred. Judging by the sounds I hear, I think it contains mostly European starlings, red-winged blackbirds and brown-headed cowbirds as well as common grackles, but I can’t get a close, long look at them before they fly off.

A mixed flock of red-winged blackbirds and common grackles

A mixed flock of red-winged blackbirds and common grackles (Photo by Nancy Magnusson on Flickr, Creative Commons license)

I remain still as a small flock appears and a few linger in the treetops while the others move on. I see bright yellow eyes and long tails. They are common grackles with a few smaller, bright-eyed birds that may be rusty blackbirds. Most blackbird flocks are mixed during migration, and common grackles are often part of red-winged blackbird, European starling and brown-headed cowbird flocks.

Later, I learned that common grackles, nicknamed “crow blackbirds,” use the hard keel of the inside of their upper mandibles to saw open acorns, scoring the outside of the acorns’ narrow ends and biting them open. Since we have had a bumper crop of acorns, I imagine they were feeding on their way south.

Common grackles (Quiscalus quiscula) breed in Canada from British Columbia in the west to Newfoundland in the east and south across the eastern and midwestern United States to the Rocky Mountains. They are partial migrants within North America, averaging 330 miles southward, and most spend their winters in the Mississippi Valley where grain fields are plentiful. Still, although they are abundant regular migrants in Pennsylvania, flocks may linger in the intensively farmed Piedmont region or at birdfeeders filled with grain.

A flock of common grackles on a communal winter roost

A flock of common grackles on a communal winter roost (Photo by Vilseskogen on Flickr, Creative Commons license)

Farther south and east they form a part of communal roosts during the winter that may contain as many as a million birds. They are partial to evergreen trees near agricultural areas and are notorious in farming circles for their love of grains, especially corn. They eat ripening corn as well as corn sprouts and are considered the number one threat to corn crops.

Common grackles are handsome birds, about the size of mourning doves, and only appear to be black. But seen closely in the sunlight, their heads are a glossy purple and their bodies a bronze-toned iridescent. They have long legs and long, keeled tails, flat heads, and bold yellow eyes. They waddle around on their legs and peck for food like chickens.

Because they sometimes eat other birds, eggs, and nestlings, many birdwatchers aren’t fond of them. These clever blackbirds have been known to steal worms from robins, follow plows to catch insects and rodents, pick leeches off the legs of turtles, wade into water to catch fish and even soak dry bread in water before eating it. Common grackles are omnivorous birds that thrive in our human-made environment and even pick through garbage.

A common grackle carrying a caterpillar for its nestlings

A common grackle carrying a caterpillar for its nestlings (Photo by Paul Hurtado on Flickr, Creative Commons license)

On the other hand, they also eat wild fruits, tree seeds, beetles, grasshoppers, caterpillars, spiders, and salamanders, with insects forming 25 to 30% of their animal diet. However, their year round diet does average 70 to 75% seeds and fruits, most of which are agricultural grains and seeds.

Like other blackbirds, they are songbirds even though most descriptions of their songs use words such as “harsh,” “squeaky,” and “nasal”—songs ornithologists believe they learn from adults in winter roosts. But songbird expert Donald Kroodsma, in his Listening to a Continent Sing, writes, “I would sit quietly in a colony, savoring their ‘rusty hinge’ songs, the croaking, squawky, far-from-musical, third-of-a-second readle-eaks to my naked ears, knowing that they’re full of exquisite detail when slowed down. I hear each bird with its slightly different song, how females sing, too, how pairs in a flock are identifiable by how rapidly they respond to each other’s song, how intimate exchanges within the colony are mediated with all those harsh chack and chaa and jit calls.”

A male common grackle

A male common grackle (Photo by Vkulikov in Wikimedia, Creative Commons license)

The male common grackles arrive on their breeding grounds a week before the females. Here in Pennsylvania they may arrive as early as the last week in February during mild winters and as late as the second week in April.

Once the females arrive, pair formation begins with groups of males flying after a slow-flying female, a male chasing a female at high speed, and a male and female flying slowly next to each other. Eventually, they pair up and mate.

The female selects the nest site, but she may change her mind in the middle of nest-building and start all over in another place. Common grackles often nest in a colony as small as 10 pairs and as large as 200 or they may nest singly. Usually, they nest at the top of evergreen trees near agricultural fields, residential areas, or even woodlands. Almost always they locate near water.

Here on our mountain we have at least one pair nesting somewhere along our hollow stream, and I suspect they nest either atop a white pine or hemlock tree, although some grackles choose deciduous trees and even shrubs as nest sites. Occasionally, they will nest in tree cavities, birdhouses, barns, or in the massive, occupied nests of ospreys or great blue herons, feasting on the leftovers that fall from the larger birds’ nests.

A male common grackle gathering nesting material

A male common grackle gathering nesting material (Photo by OHFalcon72on Flickr, Creative Commons license)

Nest-building in Pennsylvania has been documented as early as March 16 and as late as June 30, but from April 18 to May 28 are the most common dates.

Female common grackles build their nests, sometimes aided by the males. The nests are bulky cups, six to nine inches across, of twigs, leaves, and grass with paper and string if they’re near human habitations, plastered with mud inside and lined with fine grasses. They can build their nests in as little as a week and as long as a month and a half in the case of one dawdling female.

They then lay one to seven eggs of variable colors from almost white to light blue, pearl gray, and even brown. Most have blackish brown scrawls and/or spots. Normally a female has only one brood. The females incubate on their own, spending most of their days and nights on their eggs, only getting off to eat, because most males desert their mates during this time.

A baby common grackle

A baby common grackle (Photo by Donna Dewhurst, U.S. Fish and Wildlife Service, in the public domain)

Incubation lasts 11 to 15 days. Once the eggs hatch, the males rejoin their mates and, while the females brood the nestlings, the males do much of the feeding for the first few days. Then both feed the nestlings during the 10 to 17 days they remain in their nests and afterwards as fledglings for several weeks until the first of July or thereafter when they join roosting flocks.

Of course, all does not always go well during this time, and they lose close to half their eggs, nestlings, and fledglings to predation or human impact. Fox squirrels eat eggs and nestlings, rat snakes eat nestlings and gray squirrels and raccoons eat eggs. Eastern chipmunks and free-roaming, domestic cats consume the young. Raptors, including Cooper’s hawks, northern harriers, and red-tailed hawks and short-eared owls and great horned owls also prey on common grackles at all stages of their lives.

Still, common grackles thrived during the first half of the 20th century, but from 1966 to 2014 they declined 58% according to the North American Breeding Bird Survey, and now their global population is estimated at 61 million birds. While they are still abundant and widespread, scientists from the North American Bird Conservation Initiative have drawn up a list of 33 United States common birds that have lost over half their global population during the last four decades, and in The State of the Birds 2014 report, common grackles made the Common Birds in Steep Decline list.

A male common grackle feeding its nestlings

A male common grackle feeding its nestlings (Photo by Larry McGahey on Flickr, Creative Commons license)

The Second Atlas of Breeding Birds in Pennsylvania estimated our population of common grackles at 1.5 million and one of the most abundant breeding bird species in the commonwealth. Still, our population has declined 1.9% per year from 1966 to 2009. Scientists don’t know why they are declining throughout their range since they are incredibly adaptable. But because they are a threat to agricultural crops, lethal methods have been used against them in some areas.

Lately, research has been uncovering the dangers of neonicotinoids, widely used in insecticides, to birds and insects. According to the American Bird Conservancy, whose scientists have been researching these chemicals for years, neonics, as they are called, persist in the soil for months and even years and can affect entire food chains (Bird Conservation Winter 2016, p.7).

“A single seed coated with a neonic,” they write, “is enough to kill a songbird.”

So even though common grackles are still common, ornithologists haven’t forgotten that once billions of passenger pigeons roamed our continent. And then they were gone. They hope by acting now and figuring out what is causing the steep decline of common grackles and 32 other bird species, they can keep them common for future generations.