Monthly Archives: September 2020

Arctic tern migratory champion among world’s birds

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

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.