Prothonotary Warbler

Scientific Name: Protonotaria citrea
Classification: Nongame Species
Abundance: Common throughout the Coastal Plain; uncommon in Piedmont; rare in mountains

The prothonotary warbler is a Neotropical migratory species that breeds in North Carolina. It is a small, well-proportioned songbird measuring about 5 ½ inches in length. The male sports rich golden-yellow feathers on its head and belly. Its back is more olive yellow, and its wings a slate blue with no wing bars. The female’s coloring is similar, but duller. Prothonotary warblers have long, slender, pointed bills and shiny black eyes.

As the temperatures warm in spring, prothonotary warblers and other migratory songbirds move from the tropics to North America to breed. Prothonotaries prefer wooded, wetland habitats such as swamps, flooded bottomland forests, beaver ponds and streams with dead trees.

Courting begins after they arrive in late March and early April, with the male fluffing and displaying his plumage to a potential mate. Prothonotaries are unique in that they build their nests inside natural cavities made by woodpeckers and chickadees, or other ready-made cavities such as nest boxes or mailboxes. Males will line potential nest cavities in his territory with moss, but the female will ultimately select which cavity is best to use. She will then build the nest with fine grasses, twigs, bark, moss, and dead leaves to form a neat cup. Typically, they nest about 2 to 33 feet above ground and usually over water depending on nest cavity availability. The protective woods provide food as well as shelter. Prothonotary warblers prefer to forage near the ground, but not on it, feeding on insects, spiders, and snails around tree trunks, on long limbs and in shrubs. Nearly all of their feeding is in the vicinity of water.

With suitable conditions, prothonotary warblers usually attempt to breed twice in North Carolina. The first brood appears in early May, and the second in late June. The female incubates three to seven creamy white eggs with purple spots for about 13 days. Often the male feeds her as she warms the eggs. When the eggs hatch, both adults tend to the young. Sometimes, several prothonotary warblers may chase or “mob” a predator such as an Eastern screech owl to defend a nest or territory. Snakes also prey on these tiny songbirds. Fledgling warblers leave the nest in 10 to 11 days, but the bird family will remain together for a short time in the same territory. Prothonotary warblers typically do not roost, flock or migrate together in large groups.

Regulations

The prothonotary warbler is a nongame species with no open hunting season. Like other songbirds, warblers are federally protected under the Migratory Bird Treat Act. Because they are federally protected, it is illegal to harm them, their nests or their eggs. 

Management

N.C. Wildlife Resources Commission biologists survey prothonotaries, along with other songbirds, through the Breeding Bird Survey (BBS), which is the largest standardized survey method for breeding birds in the world. Routes have been surveyed across the continent for decades. Each 25-mile route is surveyed at least once each breeding season. A point count (location where all birds are identified by sight or sound) is taken every 0.5 miles. Data are analyzed over the decades to help determine bird population levels and changes over time.