Monthly Archives: September 2020

Nighthawks share the skies with many other migrants

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Photo by Dr. Thomas G. Barnes/ USFWS • A common nighthawk perches on a low clump of vegetation during a rest period. Nighthawks are known for migrating in large flocks.

Autumn’s a chance for me to indulge my passion for warblers, with a few dozen species of these songbirds passing through the region in the span of a few weeks. They’re not the only migrating birds worth watching, however, as a recent Facebook post reminded me.

John Whinery, a fellow birder who resides in Fall Branch, Tennessee, reported some interesting observations Sept. 6 on Facebook.

“Been watching several hundred common nighthawks the last few nights fly down the valley next to the farm,” John wrote in his post. He also reported that he saw a female Northern harrier fly by at eye level about 20 feet from him as he watched the migrating nighthawks. The Northern harrier, once known as the “marsh hawk,” is one of many raptors known to migrate. 

Like such birds as warblers, vireos, thrushes, tanagers, flycatchers and hummingbirds, the common nighthawk, is a neotropical migrant. In addition, the common nighthawk has one of the longest migration routes of any North American bird. Twice a year, these birds migrate for distances ranging from 1,600 to 4,200 miles. Nighthawks that spend the spring and summer in Canada travel to southern South America for the winter months. 

With September advancing on the calendar, I have been keeping an eye on the treetops for passing warblers, vireos and tanagers, but I also remember to direct my gaze to the skies. Forgetting to look skyward could result in missing the passage of such varied migrants as chimney swifts, broad-winged hawks and common nighthawks.

So, what is a common nighthawk? First, this bird, despite what is implied by its name, is not a hawk. It’s also not strictly nocturnal. Particularly in the fall, nighthawks are active during daylight hours when engaged in catching winged insects. Outside of fall migration, these birds can often be observed over large parking lots or well-lit streets, snatching up insects swarming around the light poles.

The common nighthawk is one of three members of the nightjar family found in the region during the summer months. The other two nightjars are the whip-poor-will and chuck-will’s-widow, birds that produce their namesake vocalizations in the nocturnal hours. Both of these species migrate, but they don’t take the dramatic approach employed by nighthawks. Each fall, common nighthawks form large flocks, ranging in size from dozens to hundreds or even thousands of individuals, as they migrate south for the winter.

Photo by Skeeze/Pixabay.com • A common nighthawk chooses a perch atop a fence post for a survey of its surroundings.

Unlike whips and chucks, the common nighthawk isn’t active only after dark, which makes it much easier to observe these birds. They look somewhat like swifts and swallows but are much larger. They are brownish-gray birds with pointed wings and forked tails. They are easily identified by distinctive white patches on the underside of their wings.

The nightjar, or Caprimulgidae, family of birds is also sometimes known as “goatsuckers.” Apparently, in trying to explain the nocturnal tendencies of these birds, the Greeks came up with the imaginative but erroneous idea that birds like nighthawks liked to sneak into barns and have a meal of fresh goat’s milk. In reality, nighthawks feed almost exclusively on insects, including ants, wasps, beetles, caddisflies, moths, mayflies, flies, crickets, grasshoppers, and other insects. They capture much of their insect prey on the wing.

There are almost 80 species of nightjars in the world. Less than 10 occur in North America. Many of the common nighthawk’s relatives have been given descriptive names, such as long-trained nightjar, collared nightjar, spot-tailed nightjar, red-necked nightjar, golden nightjar, fiery-necked nightjar, swamp nightjar, pennant-winged nightjar, lyre-tailed nightjar, little nightjar, sickle-winged nightjar, rufous-bellied nighthawk, short-tailed nighthawk, sand-coloured nighthawk and least nighthawk.

So, keep looking skyward. The next flock of migrating common nighthawks may fly over your home. These flocks are usually on the move throughout September.  I’ve managed only three sightings of solitary nighthawks so far this migration season, which falls far short of the number John Whinery reported at his farm. 

I will keep watching the skies. Nighthawks can also appear almost magically, as if out of thin air. First, observers may see one of two birds, then several, followed quickly by dozens or sometimes hundreds as they wheel and cavort in the skies overhead with impressive grace and agility. I’ve seen flocks that would easily number more than 500 birds in locations throughout the region, although flocks often number only a couple of dozen birds. 

Photo by Jean Potter • A common nighthawk rests on a metal railing.

Warbler parade imminent as September advances

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Photo by Mickey Estes/Pixabay.com • A pine warbler takes a brief rest on a perch during a break from foraging for insects.

I detected some signs of migration during a backyard lawn chair birding session on Thursday, Sept. 3. A croaking great blue heron circling the property, the shrill cries of cedar waxwings, scolding vireos, and the intermittent buzz of hummingbird wings all contributed to the background noise. 

The first warbler of the season, a quick blur of yellow and white, disappeared into the green and thus escaped identification. That’s the way of it: Sometimes, you identify the bird, but at other times it slips past without lingering enough for that moment of confidence. You have to love September, even if the birds are entirely ignorant of pages on a calendar. As summer wanes, the pace of migration has spiked. If that first warbler got away, I know others will follow behind it.

Some of them will have fanciful names like blue-winged warbler, black-throated blue warbler, Blackburnian warbler and American redstart. Each of the warblers exists as a sort of magnet to induce me to keep binoculars always close at hand.

 

The 50 or so species of warblers that make their home in the eastern parts of the United States and Canada during the spring and summer months are now winging their way south.  The blackpoll warbler, which holds the distinction for the longest migration of any species of New World warbler, will journey from the forests of Canada to spend the colder months in northern South America. Because of a peculiarity of this bird’s fall migratory habits, birders in Northeast Tennessee are far more likely to see this late-arriving warbler in May than in the autumn.

A few warblers — pine warbler, magnolia warbler and palm warbler — are named for trees for the simple reason that their European discoverers happened to first observe them in the branches of their namesake trees.

Photo by Bryan Stevens • A Palm Warbler forages along a chain-link fence.

For most of these warblers named to honor various trees,  their common names are, at best, a misnomer. Throughout most of its life, the palm warbler doesn’t even encounter palm trees. Johann Friedrich Gmelin, a German naturalist who lived from 1748 to 1804, saddled the palm warbler with its inappropriate name. Gmelin based his naming of the bird on the fact that a specimen had been collected on Hispaniola, an island in the Caribbean with an abundance of palm trees. Gmelin published several textbooks in the fields of chemistry, pharmaceutical science, mineralogy, and botany. He also had a hand in publishing a catalog of scientific names for various species, including some birds that had until that point never been given a species classification. Thanks to his efforts, the palm warbler has forever been linked with a type of tree that is, at best, entirely incidental to the bird’s life cycle.

The same is true for the Magnolia Warbler, which would have been more suitably named the spruce or fir Warbler, as the species is highly dependent on northern coniferous forests as nesting habitat. The pine warbler, at least, restores credibility to some of the early experts who have these tiny birds their common names. The pine warbler does indeed prefer stands of pine trees, showing particular favor for pitch pines.

Photo by Bryan Stevens A Yellow-throated Warbler makes a migratory stop in my yard on the first day of September.

These three “tree warblers” are all fairly common fall migrants, making stops in gardens, backyards and woodland edges throughout Northeast Tennessee, southwest Virginia, and western North Carolina. They and their relatives will make the remaining weeks of September and early October an exciting time for warbler enthusiasts. 

 

Arctic tern migratory champion among world’s birds

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September’s arrival puts fall migration into overdrive. The birds that returned this past spring — the warblers, vireos, tanagers, grosbeaks, flycatchers and hummingbirds — have begun or are beginning to make their way back to the locations where they will spend the winter months far from the cold, bleak conditions over most of North America.

Photo by Jonathan Cannon/Pixabay.com • The Arctic tern outdoes all other birds when it comes to migration. These seabirds journey from their Arctic nesting grounds to spend the winter around the Antarctic, a journey of some 50,000 miles a year.

Some of these birds migrate out of the tropics to avoid competition. Others find North America a land of abundant, albeit temporary, resources. This land of plenty offers a wealth of insects, seeds, fruit and other nourishing, nutritious food to help parent birds keep their strength while they work to ensure their young thrive. Of course, once the bountiful period concludes, they return to the tropics of Central and South America to winter. Those that do so successfully will make the journey back to the United States and Canada in the spring.

The phenomenon of migration isn’t exclusive to the neotropical migrants of the New World. Birds in other parts of the world migrate, too. Waterfowl, shorebirds and raptors are among some of the families of birds that stage impressive migrations.

Photo by Bryan Stevens • A female scarlet tanager is a study in contrast from her mate with her dull greenish-yellow plumage being much less vibrant than the male’s bright red and black feathers.

The Arctic tern, for example, truly takes migration to extremes. This small seabird travels each year from its Arctic nesting grounds to the Antarctic region, where it spends the winter months. Put into terms of mileage, the Arctic tern can travel about 50,000 miles in a single year. For a bird with a body length of about 15 inches and a wingspan of about 28 inches, this incredible migration is an astonishing feat. These statistics permit the Arctic tern to easily lay claim to the title of champion migrant among our feathered friends.

According to the website for National Geographic, Arctic terns face a serious threat from climate change. In a profile on the tern at its website, National Geographic warns that Arctic terns are projected to lose 20 to 50 percent of their habitat due to the temperature changes linked to climate change. They also face loss of habitat due to encroachment by human activities such as oil drilling.

The ruby-throated hummingbird, a favorite of many bird enthusiasts living in the eastern United States, makes an impressive migration each year. Just to reach the United States, these tiny birds undertake a strenuous journey. They leave their wintering grounds in Central America to return to the United States and Canada for the nesting season. Most of these tiny birds, which are barely four inches long, make a non-stop flight of more than 500 miles across the Gulf of Mexico. The journey can take almost an entire day. With the end of summer, the entire population of ruby-throated hummingbirds, increased by a new generation of young birds, makes the Gulf crossing for a second time in a year to return to the American tropics for the winter months.

Photo by Bryan Stevens • A ruby-throated hummingbird visits a feeder for a sip of sugar water.

Among North America’s buteo hawks, which includes raptors such as red-shouldered hawk and red-tailed hawk, the broad-winged hawk stands out as a dedicated migrant. These hawks form flocks that at times number in the hundreds or thousands as they sail and glide on thermals rising over various mountain ranges. These hawks and other raptors are well-known in the region for migrating past the Mendota Fire Tower in Southwest Virginia every September and early October.

The broad-winged hawk’s counterpart in the western United States is Swainson’s hawk, which shares the broad-winged hawk’s inclination for migrating in large flocks. Swainson’s hawk is named for William John Swainson, the famous 19th century English naturalist for which Swainson’s thrush is also named.

The hooded warbler, my favorite member of the migratory New World warblers, migrates back to Mexico and Central America for the winter months after nesting during the spring and summer in a range concentrated in the southeastern United States. The males, after going quiet in late summer, have started singing on occasion from the shaded woods around my house. I think this has more to do with restlessness as they prepare for to depart on a migration flight that will take them to the balmy Caribbean, Mexico and Central America while we shiver through the months between October and April. It’s not a migration of an incredible distance, but it’s still quite an accomplishment for a bird only five inches long and weighing less than half an ounce.

Photo by Jean Potter • A male hooded warbler flits through the foliage of a rhododendron thicket.

Fall’s a great time to witness the variety of avian life. Look for some of these migrants passing through your yards, gardens or favorite birding spots.

 

 

 

Green herons, one of the smaller wading birds, often overlooked as they lurk near water’s edge

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Photo by Bryan Stevens • A Green Heron elevates a shaggy crest of feathers, a behavior often initiated when the bird feels alarmed.

Byron Tucker and Ricky Dunklin, friends from Atlanta, contacted me on Facebook to ask if I could help identify a bird they had photographed during a trip to Sunset Beach in North Carolina in early August. When I saw the photographs I recognized that the visitor to a small dock at their vacation spot was a green heron.

Photo Contributed by Byron Tucker/Ricky Dunklin • A Green Heron visits a dock at Sunset Beach in North Carolina.

Green herons are not restricted to coastal areas, but it was still somewhat unexpected when I stepped onto my front porch on Aug. 19 and saw a green heron flying at treetop level. I suspect the bird had been perched in one of the tall trees on the ridge behind my house. The slamming of my front door probably spooked the bird into flight.

Green herons and other wading birds are usually quite abundant in wetlands across the country in late summer. The scientific name — Butorides virescens – of this bird comes from a mix of Middle English and Ancient Greek and roughly translates as “greenish bittern.”

Photo by Bryan Stevens • A Green Heron grasps a perch overlooking a small creek in Erwin, Tennessee.

There are only two other species in the genus Butorides — the lava heron, which occurs on some of the Galapagos Islands of Ecuador, and the striated heron, which is found in wetlands throughout the Old World tropics from West Africa to Japan and Australia. This heron, which is also known as the mangrove heron, also occurs in South America.

The green in the bird’s plumage appears as a dark green cap, as well as a greenish back and wings. Adult birds also have chestnut-colored neck feathers and a line of white feathers along the throat and belly. These herons often assume a hunched position, which can make them look smaller than they actually are.

It’s been a good summer for wading birds. In addition to the green heron, a great blue heron has been lurking in the creek in front of my home and at my fish pond. Much larger than the green heron, the great blue heron has not escaped the notice of a local flock of American crows. The crows harass the heron whenever the larger bird takes flight.

On the first day of August, I stopped with my mom at the pond at Erwin Fishery Park. We were treated with an observation of a great egret fishing along the edges of the pond. Egrets and herons are known for wandering outside their normal range in late summer after the nesting season has concluded.

Photo by Bryan Stevens • A young Green Heron rests at the edge of a pond.

Keep alert when walking along the trails in Erwin, Tennessee, and you may catch sight of one of these interesting herons or egrets, too. The edges of the fish pond at Erwin Fishery Park is also a reliable haunt for green herons. Farm ponds in the countryside around Jonesborough, Tennessee, as well as wetland habitat around the town’s Persimmon Ridge Park, are also good places to look for this small heron. The wetlands at Sugar Hollow Park in Bristol, Virginia, is another dependable location for seeing this small heron. Most green herons will depart in late September and early October. This small heron retreats from the United States during the winter season but will return next spring in April and May.

Photo by Bryan Stevens • Green herons are short, stocky herons that can assume some comical poses.

The green heron’s range during the nesting season includes Canada and much of the United States. Green herons will sometimes form loose nesting colonies, but at other times a pair will choose a secluded location as a nest site. The female will usually lay from three to five eggs. Snakes, raccoons and other birds such as crows and grackles are potential threats to eggs.

For the most part, the population migrates to Central and South America for the winter months. A few herons — great blue heron and black-crowned night heron — remain in the region throughout the year, even enduring the cold winter months in Northeast Tennessee, Southwest Virginia and Western North Carolina.

These herons are probably more common than we realize. They are skilled at blending with their surroundings, but sharp eyes can find these herons around almost any body of water, whether it is pond, marsh, river, creek or lake.

They usually depart the region in October, so the remaining days of August and September provide opportunities to observe both resident green herons and their migrating kin.

Photo by Bryan Stevens • A Green Heron finesses a captured tadpole in its bill.