What Is It Wednesday: Prothonotary Warbler

Name: Prothonotary Warbler (Protonotaria citrea)

Prothonotary Warblers are a unique Carolinian Zone species. From head to belly, this bird is a bright golden-yellow with wings and a backside of olive-green and a dark blue-grey at its tail end. Compared to most other Warblers, they have unusually long bills and short legs. Their longer bills are essential for nest building - in North America, they are the only species of Warbler that creates its own nesting cavity by excavating dead or dying trees. They will also nest in pre-existing cavities made by Chickadees and Woodpeckers, natural cavities, and nest boxes. They sing a very clear and fast “Tsweet-tsweet-tsweet-tsweet”, which you will primarily hear in deciduous forests of the Carolinian Zone. Their foraging habits take place in the forest understory and on the ground, where they slowly hop around, looking for a tasty meal.

Their preferred breeding habitat is in forested wetlands, home to silver maple, ash, yellow birch, and other tree species in the warm and wet Carolinian climate. Males will pick out several potential nesting sites within their territory before approaching a female. Once a female mate has been chosen, the male will dance about the exterior and interior of the nesting site to entice the female to look inside and see its superiority (the female gets the last say on which nesting site is the best), then the nest building begins. Males will have already placed a layer of moss in the bottom of the nest as part of the temptation game for the female. The female will then place bark, grasses, leaves, and the like to finish it off. The female will lay about 4 to 6 eggs, which will be aggressively protected by both the male and female.

The Prothonotary Warbler is an endangered species in Ontario. These birds face many threats to survival, such as nest predation from raccoons and snakes, as well as other birds that act as nest parasites, like the Brown-headed Cowbird. Although, the primary threat to this species is habitat loss and destruction. Prothonotary Warblers are habitat specialists, meaning they have very specific requirements which limit suitable breeding habitat. When dead and dying trees are removed from the forested wetland landscape, these birds will have next-to-no places to breed. Some effort has been given towards creating and installing nest boxes with predator guards for Prothonotary Warblers to increase the likelihood of nesting success. This species is also one of the several endangered species within in the Carolinian Zone that is protected through the Vision 20/20 Campaign. For more information on the campaign or to donate, click here.

Fun Fact: The inspiration behind the name of the Prothonotary Warbler came from the clothing of Roman Catholic Church papal clerks. These papal clerks, also known as Prothonotaries, wear bright yellow robes, similar to the yellow of the head, neck, and belly of this Warbler.