BIRDS OF NANTUCKET
PALMS ON NANTUCKET?
by Kenneth Turner Blackshaw
Holy Cow! Is this yet another symptom of global warming? Could palm trees actually grow here like they do on the English 'Riviera' near Torquay? No, we haven't gone that far yet. These 'Palms' are little warblers and strangely enough, we look for them on Nantucket in the wintertime.

Palm Warbler

Bird names are such a puzzle for the beginning birder. Why would a winter New England warbler be called a 'Palm?' The early European explorers first discovered this bird on the island of Hispaniola. For hundreds of years they were only known in the Caribbean. Indeed there are segments of the population that are permanent residents down there. So it was initially a bird of the palms.

It took the early French ornithologist, Charles Lucien Bonaparte, a nephew of Napoleon himself, to spot these birds traveling through the mid-Atlantic states in 1832 and realize they were the same species found down in the islands.

Scientists are still debating how many 'palm'warblers there are. In the 1950s there were two, the Yellow Palm Warbler and the Western Palm Warbler. Every time we saw one we had to decide which it was. Now they have been 'lumped' into a single species, but who knows how long it will be before they are split again. We are still encouraged to note which one we are seeing.

Wouldn't you think that the western variety would be scarcer here? Such impeccable logic - and of course - incorrect! Most of the Palm Warblers seen on Nantucket are of the western race, the result of a strange migration pattern I'll speak of later.

For now, what exactly is a Palm Warbler? They are members of the 'wood warbler' family, 30 species of which may be seen on Nantucket every year. As a child, my grandmother would point out warblers to me, but to her they were all 'wild canaries.'Most warblers are smaller than sparrows and more delicate. Hard to imagine something like this flying thousands of miles back and forth every year, but they do.

Palm Warblers are a bit odd for warblers in that they like to spend most of their lives on or near the ground. They also are continually wagging their tails to the point that 'wag-tail' is a common folk name for them. At this season, your first sign of them may come through your ears since they are rarely silent. They stay with their kind by uttering a 'sink' call note. It's kind of an, "I'm here. Where are you?" sort of message. Often they will be flying from the ground ahead of you and you may note the white flags at the corner of their tails below their greenish yellow rump.

As they light on a fence wire you will see the everpresent tail wagging, and then note a stripe over the eye. Most of the birds we see are mainly grey, but show a lemon yellow patch under that wagging tail. This is what a Western Palm Warbler looks like. If you see a bird like this but with a yellow breast, you have a Yellow Palm Warbler. The Palms we see later in the spring are more likely of this race.

Our winter 'Western' Palms migrate to the northwest to nest in Canada's Northwest Territory and Alberta. Their migration route is crisscrossed by that of the 'Yellow' Palm Warblers that mainly winter along the coast of the Gulf of Mexico, west of Florida. Yellow Palm Warblers nest in Eastern Canada, only making it into northern Maine at their southern boundary. Ninety-eight percent of Palm Warblers nest in an area known as the boreal forest, a habitat that is ever shrinking due to the effects of acid rain, global warming, and the demands of the logging industry.

These warblers not only spend most of their time on the ground, they also nest there as well. The only other warbler that does this so exclusively is their close relative, the Kirtland's Warbler, a very rare bird whose breeding range is limited to central Michigan. Man's activity in clearing the west for farming almost wiped that bird out. This habitat change was extremely beneficial to the Brown-headed Cowbird. These parasitic egg-layers were an enemy the Kirtland's had never encountered and had no defense for. Mom and Dad Kirtland's were raising cowbird chicks instead of their own. Palm Warblers nest so far north they rarely encounter cowbirds even though their nests are also on the ground.

On our recent Christmas Bird Count we found 24 Palm Warblers on our island. Last year it was 60, a huge flock seemed to be enjoying the Slosek's Farm area. Every year is different. Last winter we had Tree Swallows around until early February. This year they have all departed.

As the late Roger Tory Peterson observed, "Birds have wings; they're free; they can fly where they want when they want." And for birders, that's enough reason to keep watching for them. As Forrest Gump said about a box of chocolates, "You never know what you are

going to get!" 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.