Wake Audubon Blog

In Pursuit of a Tiny Bird in a Big Forest

i Dec 1st No Comments by

Authored by Zhuoyun “Zoe” Pu, with minor contributions by John Gerwin.

I have been studying the Black-throated Green Warbler in the Uwharries region of central NC for the past few years. This includes capturing some individual birds and applying bands and radio transmitters. I work with colleagues from the Greater Uwharries Conservation Partnership, especially Joe Poston of Catawba College, and Crystal Cockman of the Land Trust for Central North Carolina. Museum research associate Sharna Tolfree has been instrumental. Crystal and I co-host a “Naturalist Day” on the second Saturday in May. And recently I and my Museum colleague Jerry Reynolds led a day trip to the region. Crystal has several interns each spring/summer and as part of our collaboration, I get to take one into the field. This year’s intern was a young woman from China who is doing an advanced degree at Duke University in Environmental Engineering. The internship is designed to give them experience in land conservation work, including biotic surveys and in my case, some research. Often this is outside the “comfort zone” of the intern. We asked Zoe to write a little something about her experience with the work for the Black-throated Green Warbler, in May. Although not part of this story, it was great that Zoe was able to come back in June and assist for two of the 5 days when I had several Young Naturalist/Junior Curators. One of the Junior Curators is half Chinese and was thrilled to have some time chatting with Zoe. You never know what you will find in the forest.


Black-throated Green Warbler photo by Joe Poston, Catawba College

Zoe’s words –

I’ve spent the spring and early summer in pursuit of a tiny, black and yellow bird with a buzzy song – the black-throated green warbler of the Uwharrie National Forest. It’s made for an experience I’ll never forget.

As a Duke University graduate student, I’ve been an intern during May and June with the Land Trust for Central North Carolina, assisting John Gerwin, an ornithologist from the N.C. Museum of Nature Sciences, with his bird and vegetation surveys in the Uwharrie National Forest. It’s an experience I’ll remember for the rest of my life.

Our main object is the Black-throated Green Warbler. We try to collect physiological and genetic data by catching, tagging, and releasing the birds. While we work, we look for birds captured in previous years and record information about their habitat.

The Black-throated Green Warbler is a small songbird of the New World warbler group. Its black bib and bright yellow face are unique among birds of the eastern U.S. This bird can be recognized easily, not only by sight, but also by its sound, a song that sounds like “zee-zee-zee-zoo-zee” or “zoo-zee-zoo-zoo-zee”.

The warbler breeds in coniferous and mixed forest but occupies a wide range throughout its life. In August, it flies south to its Central American wintering grounds. The warbler nests in parts of North Carolina in the higher southern Appalachians, a few coastal plain sites, and in the Uwharries region. Our survey focuses on the black-throated green warblers found in the Uwharrie National Forest, which seems to be an isolated habitat for them.

The Uwharrie National Forest is primarily in Montgomery County, but extends into Randolph and Davidson counties in south central North Carolina. Most of the time, we are on Daniel Mountain or other mountains near it. According to former reports, the Black-throated Green Warbler is usually heard on the N/NE slopes of the mountains.

We begin our hike through the mountain trails at 7:30 a.m. daily, then head off the trail on a zigzag pattern through the terrain. When we hear the songs of a black-throated green warbler, we stop at one spot and play a recording of the bird’s song. In general, the male bird will be attracted by this imaginary male’s song and will come close to find out who might be challenging him for his territory. If we find a male bird is interested in our fake song, we will set a vertical net in the clearing and put a decoy model of a Black-throated Green Warbler and audio player on the branch nearby. The male will try to flush the decoy bird and get tangled in the net. The process requires a lot of waiting, watching and luck.
If we catch a bird, there’s a lot to do before he’s released. First, we put a small, numbered metal ring on the warbler’s feet to identify it. Then, using special measuring tools, we tally the bird’s wing length, weight and fat condition. During this process, we noticed that this year’s birds weigh about 8.5 grams, lighter than the typical weight of 9 grams.

Using a special needle, we draw blood from the tiny bird’s wing vein, an operation that doesn’t hurt the bird. The blood sample allows us to collect genetic data on the animal.

For our next step, we will do some vegetation surveys to know more about the warblers’ Uwharrie habitat. The Black-throated Green Warbler brings more vitality to the Uwharries, and I hope our efforts will help people understand more about the birds, so that we can live together with them long into the future.

Zhuoyun “Zoe” Pu is a Duke University graduate student who interned with the Land Trust for Central North Carolina.
Re-posted with permission from Zhuoyun Pu and the Urban Institute at UNC-Charlotte. First posted at http://ui.uncc.edu/story/black-throated-green-warblers-uwharrie-national-forest


Author Zhuoyun “Zoe” Pu with a Black-throated Green Warbler. Photo: John Gerwin

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