BIRDS OF NANTUCKET
ONE OF SIX!
by Kenneth Turner Blackshaw
If you are a Star Trek fan this may sound like Seven of Nine's sibling, but no, it is another Nantucket bird, and a charmer at that. The context is one of six species of wood warblers that nest on our island. This may be the rarest. Can you guess the others?

Prairie Warbler

When Griscom and Folger wrote Birding Nantucket in the late '40s, this bird was a bit of a conundrum. Nesting commonly on the Cape, they were more than rare here with only two records in September. I remember being thrilled to discover them nesting near the junction of Milestone and Polpis Roads ten years later, a spot now occupied by Island Lumber.

Every time I heard a new bird song I would pursue it to identify the singer. Here was this buzzy rising sequence of notes unlike anything I'd ever heard. Roger Tory Peterson's description is, "zee zee zee zee zee zee zee zee; up scale." You get the idea. The song was persistent and hard to ignore and the singer exposed and stunning at the end of a branch.

This was the first time I'd seen a Prairie Warbler in spring plumage, and it was an eyeful! Prairie Warblers are small, less than five inches from beak to tail, but brightly colored. Their Latin name, Dendroica discolor, makes them sound dull but discolor in Latin is the opposite of concolor. So the name actually means multi-colored wood warbler. The underparts are about as bright a yellow as you can imagine, contrasting with jet-black stripes on the flanks. The back is olive green but streaked with rufous. The wings show two yellow bars. If the bird flies away you often see white flags on the sides of its tail.

Often, though, it's what a bird does that makes it stand out, not just its appearance. Prairies are tail waggers. The tail is almost continually twitching, side-to-side. Only one other warbler does this - the Palm Warbler. You can eliminate 30 or so warbler species by noting behavior in this case.

Prairie Warblers are misnamed because they are generally not found on the prairie. They really like brushy pastures. They are 'edge' birds. They like areas with clearings around them. Sanford Farm is excellent habitat. So are the edges of the stands of pines on the Head of the Plains. But you are unlikely to find them in the same place year after year. This species is perplexingly cyclical. They become common over a few years, then seem to disappear only to reappear in a different location.

The activities of humans have helped them greatly as forests were cleared providing edges and openings for them. But the trend has been opposite since the early 60s. The thought is that habitat loss, both on their nesting grounds in the eastern U.S. and their wintering grounds in the Caribbean, has made life difficult for them.

They have another problem as well - the Brown-headed Cowbird. Cowbirds are nest parasites. Does this sound like one of your family members? If so, you have my condolences. Cowbirds build no nests of their own but instead, lay their eggs in the nests of other birds. Their chicks grow quickly and gobble up the food their adopted parents bring them. Anyway, Prairie Warblers are now on the Audubon Society 'Watchlist.' Sometimes I wonder if there should be a list like this for Nantucketers.

Prairie Warblers spend the summer across the eastern U.S. and we are near the northern edge of their range. Their nest is usually within four feet of the ground, made of interesting and rather cushy material. One was woven from dandelion down. Imagine how many trips back and forth that one took! Normally four eggs are laid and at this latitude they only raise a single brood.

Why do they come and go? This

is a mystery for scientists to solve. Is it habitat change - cowbird parasitism - or perhaps something that happens on the wintering grounds or migration that causes a colony to not return? This year we are hearing them sing on the Head of the Plains beyond Massasoit Bridge. If you travel out that way, listen for the 'zee zee zee' rising song.

They can be easily found here until late October and then rarely into December. We have recorded them on three of our Christmas Bird Counts so they are hardy for a member of this family, existing almost solely on insects.

Wintertime finds our birds in the Bahamas and farther south. There is a Florida race of the Prairie Warbler that loves the mangroves and doesn't see the need to migrate at all.

And the other five Nantucket nesting warblers? They are the Yellow, Black and White, Pine, the American Redstart and the Common Yellowthroat. They

are all present for duty and waiting for you to find them. I

George C. West creates illustrations for these articles. If you enjoy 'social' birding, join the Nantucket Bird Club at 8 a.m. Sundays in front of Nantucket High School for a two to three hour birding trip. Call 228-1693 for more information. To hear about rare birds, or to leave a bird report call the Massachusetts Audubon hot line at 1-781-259-8805. Ask Ken a question at: kenandcindy1@comcast.net.