Photo: Prothonotary Warbler, Edward Episcopo/Audubon Photography Awards
Bird of the Month: Prothonotary Warbler
Jessica Bigger
The Prothonotary Warbler (Protonotaria citrea), is one of only two North American warblers to nest in cavities. The other is the Lucy’s Warbler. Prothonotaries nest in cavities already established by other woodpeckers and chickadees but they will also nest in boxes designed for their specific preferences.
They prefer nests on trees over standing water, like Bald Cypress and Willow Trees, but they will also nest on the ground or in the understory. Location is important as this species chooses to nest in forests near a body of water; on the edge of lakes, streams, and alluvial floodplains or near swamps. Prothonotary Warblers forage on the ground near their nests searching for a variety of insects including mayflies, caterpillars, and butterflies.
With its bright yellow and smooth grayish blue plumage, it’s not a surprise that this warbler was named after the Roman Catholic Prothonotories (Papal Clerks) who wore bright yellow robes during mass.
Since 1966, the Prothonotary Warbler population has been declining. Population numbers have dropped 1% each year between 1966 and 2015. One of the biggest threats is a loss of habitat on both breeding and wintering grounds. Removal of snags and channeling streams reduces nesting habitat. Mangrove swamps, a prime wintering habitat, are disappearing at a dramatic rate because of an increase in aquaculture and development.
Climate change has also become another factor. As the global temperatures increase, this warbler’s summer breeding range is predicted to shift further north into Canada. Some of the Prothonotary Warbler’s habitat in the Midwest will likely become uninhabitable. As for most birds, a huge threat is spring heatwaves, which can kill young nestlings.
As with many warblers, the Prothonotary Warbler can be elusive despite its bright color. It’s sometimes easier to hear its song, a series of 5-7 “sweet-sweet-sweet…” sounds than it is to spot one.
Prothonotary Warbler, Edward Episcopo/Audubon Photography Awards