Monthly Archives: June 2017

Osprey’s fishy diet sets it apart from most other raptors

Jim and Tammie Kroll emailed me about a very interesting bird observation on the Virginia Creeper Trail last month.

They saw a bald eagle along the Virginia Creeper Trail on May 14. “It was between Alvarado and Damascus,” Jim wrote in the email. We got to see it at two different locations and watched it around 15 minutes at each location.”

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Photo by Jim and Tammie Kroll • This adult bald eagle was seen along the Virginia Creeper Trail.

He added that they talked to a woman who informed them that she also sees an eagle in the same area on the Creeper Trail.

The Krolls also shared a photo of the eagle. I’m always glad that to hear that observing the nation’s official bird is no longer a rare occurrence in the region. While I haven’t seen any bald eagles this year, I have observed a raptor that share many characteristics with them.

Ospreys, also known by the common name of “fish hawk,” occur worldwide. Ospreys migrate through the region in spring and fall, making sightings more likely along some lakes and larger rivers. I see them even more often when I travel to South Carolina, where these medium-sized raptors are common along the coast and in wetlands.

Some recently published books provide insight into the lives of bald eagles and ospreys. Teena Ruark Gorrow and Craig A. Koppie are the authors of the recent book, The DC Eagle Cam Project: Mr President and First Lady. This book profiles a celebrity pair of eagles that have nested for the past few years in U.S. National Arboretum in Washington, D.C.

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Front cover of a book by Teena Ruark Gorrow and Craig A. Koppie featuring photos of a nesting season in the life of a family of ospreys.

Gorrow and Koppie have also written other books together, including one offering a pictorial journey through an osprey nesting season. Titled “Inside an Osprey’s Nest,” this book provides an account of two fostered osprey chicks that receive new parents in a heartwarming, real-life account of a family of ospreys associated with the Chesapeake Conservancy Osprey Nest Cam.

During a recent interview, Gorrow shared that bald eagles and ospreys share more than a few things in common.

“The bald eagle, Haliaeetus leucocephalus, is America’s national bird and symbol,” Gorrow said. “It is a large raptor, or bird of prey, found only in North America. Also a raptor, the osprey, Pandion Haliaetus, is a large hawk found on every continent across the globe except Antarctica.”

Like the American bald eagle, Gorrow noted that ospreys experienced devastating health effects and reproductive failures from widespread human use of dangerous pesticides like DDT.

“By the 1970s, population numbers had plummeted to catastrophic levels for both eagles and ospreys,” she said. “Federal actions were put into place which imposed migratory bird protection and banned DDT. These measures, along with the work of dedicated scientists, conservationists and citizens, have helped these magnificent raptors recover.”

Gorrow said that when selecting a nest site, bald eagles and ospreys identify an area near water with a plentiful food supply and nearby trees. “With diets consisting mostly of fish, both require foraging areas rich in fishery resources,” she said.
During nesting season, ospreys and eagles are seen as competitors, even though food is abundant in the Chesapeake Bay region. “Bald eagles are opportunists and will usually pirate fish prey from osprey when given the chance,” Gorrow said.

Nesting season for eagles begins earlier than ospreys, so they have the upper hand in defending territories. “Eagle pairs in the Chesapeake Bay area usually lay eggs in mid-February, while the ospreys return from their southern wintering destinations around mid-March,” Gorrow said. “Ospreys generally build nests in March or April and lay eggs soon after.”

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Early naturalist and artist John James Audubon painted this work of art featuring an osprey with a fish held in its talons.

The two large raptors also demonstrate other distinct preferences.

“Bald eagles utilize living and dead (known as snags) trees as nest sites,” she said. “Eagles rarely tolerate humans near their nests.

“On the other hand, ospreys are relatively tolerant of humans and sometimes build nests on private pavilions or docks beside waterfront properties,” Gorrow continued. “They seem to favor artificial structures and often construct over-water nests on the steel supports of bridges, channel markers, navigational buoys, fishing piers, jetties, and manmade nesting platforms. Ospreys sometimes choose snags with an open treetop or claim tall, artificial structures resembling dead trees, such as towers, utility poles, television antennas, road signs and stadium lights. They also sometimes nest on chimneys and rooftops on uninhabited buildings.”

A more in-depth glance into the lives of ospreys is available in the book “Inside an Osprey’s Nest,” which retails for $24.99. When purchased through the Chesapeake Conservancy at http://www.chesapeakeconservancy.org, $10 from every purchase supports conservation programs along the Chesapeake Bay Watershed. The book is also available at http://www.schifferbooks.com, Amazon.com and other booksellers.

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To learn more about birds and other topics from the natural world, friend him on Facebook at https://www.facebook.com/ahoodedwarbler. He is always posting about local birds, wildlife, flowers, insects and much more.

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Photo by Bryan Stevens • An osprey perches in a tree along the Watauga River in Elizabethton, Tennessee.

Warblers exert special pull for many birders

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Photo by U.S. Fish & Wildlife Service • The Kirtland’s Warbler, while endangered, is slowly building its numbers with intensive human assistance. Nearly 50 different warbler species nest in the eastern half of the continental United States. The rest of the world’s warblers reside mostly in Central and South America.

I’ve been fascinated with the group of small, energetic songbirds known as warblers almost from the start of my time as a birder. Many birds have inspired poetry, but to me, the warblers are poetry. I suppose another, more down-to-earth part of my fascination is that a little effort is usually required to see these birds. Although many species of warblers spend the summer months in the region, few of them would really be described as backyard birds. That being said, I am also fortunate to live in a location surrounded by woodlands that are inhabited by several species of warblers in the months spanning April to September on the calendar.

Of course, it’s always gratifying to hear from readers who have also caught the “warbler bug” and find these tiny, colorful songbirds as fascinating as I do. Graham Gardner of Abingdon, Virginia, sent me a recent email about the warblers, an extensive family of neotropical migrants that happen to be among my favorite birds.

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Photo by Graham Gardner • A Canada warbler wears a dark necklace of feathers across its yellow breast.

“I just wanted to share another great birding experience that I recently had with my father this past weekend,” Graham wrote in an email sent on May 1. “As you know, the spring migration of neotropical migrants is upon us. My father and I decided to take a trip to Peaks of Otter Lodge in the heart of the Blue Ridge Mountains to attempt to observe some of the more difficult-to-find warblers that I had not yet checked off my life list.”
He reported that the trip was wildly successful.

“We observed 10 warbler species in total in just under two days of birding.” Among them were three species that were new for him: cerulean warbler, Blackburnian warbler, and bay-breasted warbler.

He also shared some photos. “These guys are really quite difficult to photograph,” he wrote. “They are either constantly on the move, bouncing from branch to branch, or they are high in the canopy staying mostly out of sight.”

Graham wrote that he looks forward to searching for warblers in the coming weeks as they continue to pass through, and in some cases settle in, our Appalachian Mountains.
I congratulated Graham for his success with some of my favorite birds. I also let him know that he succeeded with a bird — the cerulean warbler — that has been elusive for me over the years. It’s one of the few warblers that spend time in the eastern United States that I haven’t managed to add to my life list. The other two warblers I need are the Connecticut warbler and Kirtland’s warbler.

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Early naturalist and artist John James Audubon painted this pair of cerulean warblers, a bird that he knew as the “Azure Warbler.”

 

“The cerulean was definitely the highlight of the trip for me,” Graham noted in a second email to me.

The cerulean warbler makes infrequent appearances in the region, but it has been observed as recently as the spring of 2016 at Steele Creek Park in Bristol, Tennessee. Some other locations — Frozen Head State Park, Edgar Evins State Park and Falls Creek Falls State Park — support breeding populations of this warbler within the Volunteer State.

Unfortunately, the cerulean warbler is one of the fastest declining songbirds in the United States. Habitat destruction in its breeding range in the Appalachian Mountains and its wintering range in South America is to blame for its plummeting numbers.

Among a family of several breathtakingly beautiful species, the cerulean warbler is one of the most exquisite of its kind in terms of appearance. Adult males have pale cerulean blue upperparts — hence the bird’s common name — and white underparts with a black necklace across the breast. They also show black streaking on the back and flanks.

Beyond its uncommon status, there are other reasons why it’s difficult to lay eyes on a cerulean warbler. First and foremost, cerulean warblers prefer to forage in the treetops. In that leafy, lofty habitat, observing these warblers can be difficult for ground-bound humans.

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Photo by Bryan Stevens • The Northern waterthrush is a warbler fond of foraging near slow, flowing water.

I’ve been very close to seeing a cerulean warbler twice. During a past Spring Naturalists Rally at Roan Mountain, Tennessee, several people watched a cerulean warbler flitting in some tall trees while I struggled unsuccessfully to get my binoculars on the rapidly moving bird. More recently, I was looking for birds with fellow birder Jean Potter along the Watauga River in Elizabethton, Tennessee, for a Fall Bird Count. She found a female cerulean warbler in a tree overhanging the river, but I failed to get my binoculars on the bird in time.

So, while my luck with cerulean warblers hasn’t changed (yet), I have seen several warblers at my home this spring, including hooded warbler, ovenbird, black-throated green warbler, black-and-white warbler and Northern parula. In addition, I’ve seen other warblers — yellow-breasted chat, Cape May warbler, yellow warbler and chestnut-sided warbler — at other locations in the region.

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Photo by Graham Gardner • The black-and-white warbler, which is aptly named, is one of the most easily identified warblers.

The warblers are poetry written with splashes of movement and hints of color written across an often green background. While not easy to observe, they’re worth seeking out. Glimpsing one of these energetic songbirds is always a moment that puts a smile on my face — and in my heart.

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Bryan Stevens lives near Roan Mountain, Tennessee. To learn more about birds and other topics from the natural world, friend Stevens on Facebook at http://www.facebook.com/ahoodedwarbler. He is always posting about local birds, wildlife, flowers, insects and much more. If you have a question, wish to make a comment or share a sighting, email ahoodedwarbler@aol.com.

Readers report on robin, purple martin that stand out from other members of their flocks

 

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Photo by Jean Potter • Two barn swallows in typical plumage perch on a wire with an albino individual.

Birds of a feather, as the old saying goes, tend to flock together, but what happens when a member of the flock stands out from the rest? Although conventional wisdom mandates that being conspicuous is not helpful for most wild creatures, some of them can’t help but get attention. Different readers have brought to my attention some birds at their homes that instantly stood out.

Sara and Ed Gschwind, residents of Bristol, Tennessee, have been keeping tabs on an American robin in their yard that is showing an extensive amount of white feathers in its plumage. For the most part, this particular robin has a white head, largely white wings and extensive white in the typically red breast. “My 88-year-old mother, Nora Rockett, suggested I send a photo to you,” Sara wrote in an email.

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Photo by Ed Gschwind • A leucistic American robin enjoy time in a bird bath. Albino and leucistic birds are rather rare in nature.

Sara said that her mother, who has lived in Bristol all her life, has never seen anything like it. I replied to Sara’s email, asking for a few more details.

While the robin interacts with others of its kind, the Gschwinds haven’t seen any evidence this particular robin is attempting to nest. Ed took a photograph of the robin enjoying the water in a bird bath in the Gschwind yard.

“The robin bathes every day, and loves the water like all robins do,” Sara wrote. “The robin has been here since the robins returned three months ago. I’m trying to keep it happy.” Since the robin is a regular visitor, I agree that they’re doing a good job keeping the bird happy, since it’s not shown any inclination to leave their yard.

Tom Brake, who lives in Abingdon, Virginia, contacted me through Facebook about a male purple martin with extensive white feathers residing at the purple martin colony he has established at his home.

Purple martins are the largest member of the swallow family in the United States. Like many other swallow species, they nest in colonies. Martins are cavity-nesting birds that readily accept hollow gourds or special purple martin condominiums for nesting.

“Currently I have nests in 43 compartments with 20 being active (eggs having been laid),” Tom wrote. “Last year I had 51 pairs, and I hope to get close to being back to 60 or 70 active pairs this year. The next two weeks will be the busy time for completion of nests and laying.”

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Photo by Tom Brake • A leucistic male purple martin perches with its mate, a typical female purple martin, near a hollow gourd they may use for nesting purposes.

As for the bird showing the white feathers, Tom has named him “Leuie” because the bird is an example of leucism, a condition related to albinism.

Albinism is a genetic, or inherited, condition resulting in a complete lack of production of pigmentation. Albino birds are, for the most part, extremely uncommon. I’ve heard of a variety of birds, ranging from hummingbirds and American robins to various ducks and swallows, that have a tendency to produce albino individuals.

Leucism is another genetic mutation that causes affected birds to grow feathers that are pale or whitish overall. A faint pattern may be visible. Leucism is also uncommon, but is more common that albinism. Both the robin in the Gschwind yard and the purple martin at Tom’s home are examples of leucistic birds.

Tom noted that “Leuie” is doing well so far. “He has a mate, but their first clutch of four eggs was either thrown out by a second year male martin or discarded by themselves because they sensed non-viability,” Tom wrote in a Facebook message. “Maybe the cold, wet weather had something to do with the loss.” He noted that the same thing happened recently to two other nests.

“Leuie and mate are still using their gourd, so I expect they will re-clutch,” Tom wrote. The term “re-clutch” means that Leuie’s mate will lay a new batch of eggs and Leuie will be ready to carry out his own paternal duties to help raise any resulting young.

Albinism and leucism are not the only conditions that can affect pigment in a bird’s feathers. Some birds have the opposite problem in that they produce too much pigment, resulting in a much darker bird than what would be typical. The plumage of such affected birds is described as melanistic, which is in stark contrast to an albino bird. With a melanistic bird, the feathers are much darker than usual because of an abundance of pigment. In rare albino birds, the opposite occurs and the lack of pigment in the feathers leave them looking white. Completely albino birds also tend to have red eyes. It’s probably better for a bird to be melanistic. Albino birds tend to stick out like sore thumbs, attracting the attention of predators.

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Photo by Ed Gschwind • Compare the leucistic American robin in the bird bath with the typical robin perched in a nearby chair. Albino birds are rather rare in nature.

I’ve only seen a few albino or partial albino birds in person, although I have observed videos and photographs of such birds. During a trip to Salt Lake City, Utah, in 2006, I observed an albino Brewer’s blackbird. An albino blackbird is almost an oxymoron. This particular blackbird had a white upper body and head and a black lower body. At first, I thought it might be a small tern, but closer observation — and identification of the birds with which it was associating — eventually confirmed that it was a Brewer’s blackbird, a common species in Salt Lake City.

Those observations remain my best looks at albino birds in the wild. I’ve also seen partial albinos, including an American Crow with white feathers in its wings that inhabited the woodlands and fields at my home for several years. I’ve also observed a couple of American goldfinches over the years that would probably qualify as leucistic birds.

A few years ago, I saw an albino Red-tailed hawk while driving between Erwin, Tennessee, and Asheville, North Carolina, on Interstate 26. The hawk was often present near the North Carolina Visitors Center. I’ve also heard from readers over the years about birds such as American goldfinches and downy woodpeckers exhibiting albino tendencies.

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Photo by Jean Potter • This partial albino red-tailed hawk was spotted for several years near the state line dividing northeast Tennessee and western North Carolina.

These issues involving the absence or abundance of pigment can complicate bird identification. After all, all-white birds, from snowy owls and tundra swans to great egrets and snow geese, do exist in nature. Even in these birds, however, there’s usually some other color present to break up the uniformity of the bird’s plumage. Keep in mind that such rarities as albino individuals of such common species as house finches and American robins can show up at your feeders or in your yard. It’s just another way birds constantly surprise us.

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To learn more about birds and other topics from the natural world, friend him on Facebook at https://www.facebook.com/ahoodedwarbler. He is always posting about local birds, wildlife, flowers, insects and much more.