SPRING 2001/VOLUME 15, NUMBER 2

Cornell Lab of Ornithology
Become A Member
The Birdhouse Network

Citizen scientists can provide nest sites and valuable data on the "most-wanted" Prothonotary Warblers

Many readers wrote to The Birdhouse Network (TBN) in response to "TBN's Most Wanted List," published in the last issue of Birdscope, with particular concern for the Prothonotary Warbler. Breeding Bird Survey data show a population decline of 2.7 percent per year throughout their breeding range from 1980 to 1999. Habitat loss appears to be the primary cause of their decline. With habitat loss comes a loss of nest sites, and Tree Swallows, House Wrens, and mice often outcompete Prothonotary Warblers for those that are available. Depredation of nests and frequent parasitism by Brown-headed Cowbirds are also factors in their decline.

	The highest concentrations of Prothonotary Warblers occur in the Lower Mississippi Valley and the South Atlantic Coastal Plain, but some nest as far north as southern New England.
Prothonotary Warblers are our only cavity-nesting Warbler. They typically search for prey close to the ground but will forage higher when feeding nestlings. They are often seen gleaning flies, beetles, spiders, and caterpillars from tree trunks, branches, and fallen logs. Photo by C. Hardy

TBN received only 16 records of this species from 1997­2000. We need far more. Won't you consider helping us collect data about them? Here's a brief overview, to help you get started:

• Look for these golden gems along rivers or in wet lowland areas of the southeastern United States. They are easily distinguished by a bright yellow head and breast offset by a greenish back and blue-gray wings.They are one of only two North American cavity-nesting warblers. (The other is Lucy's Warbler, which breeds in the Southwest.)
• Listen for their loud, sweetly whistled song, zweet zweet zweet zweet zweet.
• They arrive on the breeding grounds between mid-March (Gulf Coast) and mid-April
• (northern regions). The male claims suitable sites by placing bits of moss inside potential cavities on his territory. The female selects a cavity and fills the hole with dry leaves, twigs, bark strips, lichens, and more moss, which may play a role in adjusting the microclimate of the nest box.
• Potential nest sites include abandoned Downy Woodpecker holes or cavities in snags, stumps, or rotten logs. They also accept nest boxes and may even settle into glass jars, mailboxes, empty tin cans, and even coat pockets.
• Because they will nest in virtually anything, the Prothonotary Warbler may be one of the easiest cavity-nesting birds to attract to a nest box. We adamantly recommend using a standard songbird nest box for
• most cavity-nesting species, especially in more northerly locales. However, studies in Tennessee have shown that a milk carton nest box is durable and provides adequate insulation for prothonotaries breeding in the South.
• Ideally, your nest box should be erected by mid-March in southern regions and by mid-April in the northern part of their range. Be sure to set it up near water (over water is best, to guard against predators) in a wooded area with standing or slow-moving water and ample shade. Preferably, keep it away from areas where wrens are likely to move in.

Thanks for your interest and concern for this beautiful little bird. We hope to receive Prothonotary Warbler reports from you this year!