Bird Lore: Palm Warbler

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Palm Warbler (Photo by LeRoy VanHee)

The Palm Warbler is a bird seen on occasion in Western Washington in winter. There are only three records of this species in Edmonds in the last thirty years: 2004, 2013, and 2016 continuing to now. I have avoided featuring rare birds in this column for two reasons. First, rare birds in Edmonds usually don’t linger for more than a day. Second, most readers probably would not have an opportunity to see the bird.

The current Palm Warbler arrived in the Edmonds Bowl in early November and there were sporadic sightings until mid-December. It has been at Marina Beach pretty steadily since Dec. 16, when it was spotted for the Christmas Bird Count. Marina Beach visitors may well encounter this drab “Western” Palm Warbler with its bright yellow undertail. Tail-bobbing is a characteristic unique to this warbler while it forages on the ground.

Photo by Carol Riddell

Insects and berries compromise the Palm Warbler’s diet. The bulk of its diet is mosquitoes, flies, small beetles, caterpillars, aphids, ants, bees, grasshoppers, and spiders. It also eats a lot of vegetable matter, including raspberries, bayberries, and seeds. During breeding season it gleans insects from the foliage of black spruce, tamarack, and cedars. It also flies out to catch insects in midair. In winter, it does much of its foraging by walking and hopping on the ground. This is the behavior most viewers are seeing now at Marina Beach.

Almost all breeding sites are in boreal areas of Canada. The Palm Warbler nests in sphagnum bogs with scattered spruce, cedar and tamarack trees. The western race breeds in dry pine barrens of boreal forests, where ground cover includes blueberry, bearberry and sweet fern. The female builds the nest, which is an open cup of dry grass stems and shredded bark. It is lined with feathers. The nest is often concealed under a clump of grass and on top of a sphagnum moss hummock.

There are usually four to five eggs, probably incubated by both parents for about 12 days. Both parents feed the young birds, which fledge about 12 days after hatching. The young can fly short distances a day or two after leaving the nest. The Palm Warbler is one of the early nesters, arriving on its breeding grounds in early April. Because of this, it probably has two broods per year. And some males have more than one mate.

Photo by Carol Riddell

Most of the Palm Warbler population winters along the Gulf Coast and the Southeastern states, including most of the “Western” Palm Warbler population. Very small numbers of the duller-plumaged “Western” Palm Warbler population winter along the Pacific Coast. The majority of the Palm Warbler population is the so-called “Eastern” bird. Overall, it has brighter plumage. “Eastern” refers to the portion of the breeding grounds that it uses. The “Western” Palm Warbler breeds in the more western parts of Canada.

For conservation purposes, the Palm Warbler is a species of least concern. The global population has been stable since monitoring began in 1966 by the North American Breeding Bird Survey. The population is estimated at 13 million, with 49 percent spending part of the year in the U.S., 7 percent in Mexico, and 100 percent in Canada where the species breeds.

The Palm Warbler’s song can be heard here: http://www.xeno-canto.org/189612. Its call is here: http://www.xeno-canto.org/307682.

— By Carol Riddell

Carol Riddell manages the bird education displays, on behalf of Pilchuck Audubon Society and Edmonds Parks & Recreation, at the Olympic Beach Visitor Station.

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