Sunday, May 10, 2009

What's in a Name: Wood Warblers

Yellow Warbler. Photo by David Powell
Yellow-rumped Warbler. Photo By David Powell.

Imagine sitting on the deck overlooking the Jemez River on the first beautfiul spring morning spring morning of the year. The streamside vegetation is bursting with new green verdance. As the caffeine from your coffee or tea begins to work its morning magic and the sleep induced blurriness clears from your eyes, you realize that today the world is a little different. Tiny little birds of brilliant yellow, black, green, and blue flit among the tree tops and bounce across the streamside vegetation oblivious to your presence. They’re in a hurry, these little birds, gobbling up bugs as if they’ve not eaten in a long time, hastily replenishing their fat reserves. Every so often, one of them appears to forget the business of survival, and bursts into song, often from the very top of a very exposed perch, as if he were warbling his presence to the world. Indeed, he is doing just that but, in truth, he cares little for planetary interest. His serenade is meant for only one, a certain special female.

Warblers, properly known as wood warblers, have long captivated bird watchers with their diversity, bright plumages and sprightly behavior. Most of them winter in Mexico, Central and South America, and return to our latitudes in late April and May. Down south, during the winter, they were busily eating as much as possible, mostly insects, so they could produce an entirely new set of iridescent feathers and attain prime breeding condition. They’re hungry when they arrive after their long journey, often feeding voraciously in the densest vegetation of the very tops of the tallest trees. Warbler watching is not for the faint of heart. There’s actually a name for this particular sports injury, “warbler neck”. It feels as if your binocular strap is literally going to sever your head from your body. It hurts

I clearly remember a trip to southern Arizona, to the upper reaches of the Chiricahua Mountains on a quest for rarities, one of which was the Olive Warbler. The habitat preference of this little fellow is the tip top of the tallest pines. We heard him sing almost as soon as we arrived and occasionally saw something flit way up there. My neck loudly proclaimed its discomfort as I searched through the tips of the pine forest without capturing one in my binoculars. Then, just when I was about to give up, I realized that I didn’t necessarily have to stand with bowed back and bent neck. My friend and I decided to lay down in the grass and watch from a more natural body postition. Voila Olive Warbler added to my checklist

Warbler watching is not for everyone, but some dedicated birders travel far afield to places like High Island, Texas each spring. This tiny island on the north shore of the Gulf of Mexico hosts the first trees and shrubs seen by trans-gulf migrants after flying nonstop across hundreds of miles of water, a nonstop trip of 36-45 hours across the hostile ocean. Exhausted, the tiny birds fall from the sky, resting and eating within easy sight of the average birder.

Our western warblers make and overland journey north along the spine of the continent and its watersheds. While many species migrate through, only a few stay to nest: Yellow-breasted Chat (our largest warbler), Common Yellowthroat, and Yellow, MacGillivray’s, Grace’s, and Virginia’s Warblers are the most common Jemez nesting warblers.

Insect larvae comprise the bulk of the diet of all warblers, although fruit and nectar are seasonally important for some species. Just as species occupy widely differing habitats, their feeding styles vary widely. Some are gleaners, patiently plucking insects from leaves and bark, moving slowly and reaching for the next morsel, like our Grace’s Warbler that probes pine needles, bark, and crevices in the ponderosa pine forest. Some skulk in dense vegetation, often along streams, picking insects from clusters of dead leaves on the ground or bark and vegetation just above, like MacGillivray’s Warbler. Others prefer to hang from or flutter beneath vegetation, gleaning prey from the underside of leaves, like the Wilson’s Warbler that migrates through New Mexico and breeds in our northernmost coniferous forests. This tiny, bright yellow fellow with the solid black cap is constantly on the move. In fact, “the bird that can’t stop moving” is one of the ways to help identify the species. Some warblers, like the Yellow-rumped Warbler, employ a sallying technique, flying quickly out from a perch to snatch an aerial insect, also called flycatching.

While warblers occupy themselves with survival, we humans wrestle with cataloguing and naming all things on our shared plant. It can be the cause of strife and dissension, with a heavy dose of ego. In the world of ornithologists, the honor of naming a bird is bestowed on the person that discovers the new species, but naming a bird after oneself is frowned upon by the scientific community. Changing a name, once bestowed, can be construed as scientific jealousy and cause for scorn.

Some species have names that reflect something about their biology, such as the Field Sparrow, often found in weedy fields, or Swamp Sparrow. Others are named after their song or call, such as the chickadee with its ‘chick-a-dee-dee-dee’ call. Some choose to name the newly discovered species after another individual, generally another revered scientist. However, controversy sometimes rears its ugly head when egos are overly invested in a name.

Such was the case with our beautiful MacGillivray’s Warbler. It was discovered by eminent ornithologist, John Kirk Townsend, who named it after his close friend, Dr. W. T. Tolmie, Esq., a surgeon, noted ornithologist, and entrepreneur with the Hudson Bay Company. The new species was called Tolmie’s Warbler. Later, however, in Birds of North America, John James Audubon renamed the species MacGillivray’s Warbler in honor of his close friendship with Dr. W. MacGillivray, a Scottish ornithologist and professor of natural history who had helped Audubon edit his book. Audubon’s disregard for Townsend’s prior name and MacGillivray’s lack of North American field experience have caused resentment among some western birders, who still prefer reinstating the original name. Fortunately, the warbler shares none of our concern about his name. He’s too busy just doing what comes naturally.

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