Prothonotary warbler (Protonotaria citrea)
|Size||Length: 14 cm (2)|
|Weight||c. 14 g (2)|
The prothonotary warbler is classified as Least Concern (LC) on the IUCN Red List (1).
The prothonotary warbler (Protonotaria citrea) is a small, vibrantly-coloured songbird, with a brilliant yellow-orange head and neck. The first part of this species’ unusual common name, ‘prothonotary’, alludes to the yellow hooded robes that were once worn by Roman Catholic clerks, in reference to its bright yellow plumage (3) (4) (5). The prothonotary warbler has an olive-green back, and the wings are blue-grey with black tips on the upperparts, and white and yellow underneath (3) (5).
The female prothonotary warbler is not as brilliantly coloured as the male (3). The body of the female often has green highlights and tints, especially on the crown, and the wings are duller. The belly and tail are generally whiter (3) (5). The male and female prothonotary warbler both have dark grey legs and feet, a black bill, and black eyes (3).
The prothonotary warbler is the only representative of its genus, due to the length of its bill, which is longer than other warbler species. This species’ song is a very loud ‘tsweeet–tsweet–tsweet–tsweet’ (2).
The prothonotary warbler is native to the United States, Central America and parts of northern South America (4). This species' breeding range is primarily in the central and southeastern states the U.S. (4) (5), although its range extends along Atlantic coast from New York to Florida, and west to Michigan, Wisconsin, Texas, Oklahoma, and Kansas (4).
The prothonotary warbler overwinters in Central America and parts of northern South America, particularly along the Atlantic coast from southern Mexico to South America. This species also overwinters along the Pacific coast of Costa Rica and Panama (4) (5).
The prothonotary warbler prefers to reside in wooded swampy areas and low-elevation forests, close to rivers (3). It is often found near lakes, ponds, and other large bodies of standing or slow-moving water (4). This species requires suitable tree cavities for nesting and thus is usually associated with wetland trees such as willow, sweet gum, willow-oak, black gum, tupelo, bald cypress, elms, and river birch (3) (4).
The prothonotary warbler spends the winters in mangrove forests (3).
The prothonotary warbler is unlike any other eastern U.S. wood-warbler species, as it prefers to build its nest in tight cavities (4) (6). This species is highly opportunistic and will nest in many types of small, sheltered, and cramped spaces in wet forests and swampy areas. The nest may be built in natural cavities, such as holes in trees, or in man-made cavities including next boxes and discarded refuse, such as milk cartons, cans and jars (5) (6). The prothonotary warbler may also use holes excavated by the downy woodpecker (Picoides pubescens) (4).
The diet of the prothonotary warbler consists primarily of insects, such as beetles, moths, butterflies, spiders, caterpillars, and insect larvae, which are collected from tree trunks, fallen trees and leaf litter on the forest floor. It will also feed on snails and isopods, and will supplement its diet with fruits, seeds and nectar (3) (4) (5).
The male selects and prepares a nesting spot before attracting a mate, and lines the nest cavity with moss (3) (4). The male may build “dummy”, non-use, or “trick” nests to expand its territory and to provide optional nesting sites (2). The male may stay overnight in one of the trick nests to give the impression of occupancy (2).
The female prothonotary warbler takes over nest building once a pair has formed, adding nesting materials such as rootlets, plant down, grape plants, cypress bark, sedges, tendrils, leaves, stems and leaf stalks, poison ivy, and even fishing line to the nest cup (3).
Three to seven creamy-white eggs with purplish spots are laid by the female prothonotary warbler in late May to mid-June (3) (6) (7), and the female incubates the eggs for around 12 to 14 days (3). The eggs usually hatch within 12 hours of each other, and the newborn nestlings remain in the nest for the next 10 to 11 days, until the adults coerce the young to leave the nest cavity (3). Both of the adult prothonotary warbler’s share parental responsibilities, such as bringing food to the young and protecting them against intruders. The adults continue to supervise the fledglings for around 35 days after they have left the nest (3) (4).
The prothonotary warbler is extremely territorial during the breeding season. The male defends the territory by chasing away intruders or snapping its bill, while the female commonly enters into bill-snapping disputes with other females. The prothonotary warbler is generally social during the rest of the year (3).
Although currently classified as Least Concern (LC) by the IUCN Red List, breeding populations of the prothonotary warbler are highly localised, due to its very specific habitat needs and increasing habitat loss (3).
Mangrove sites along the coast of Central and South America are being destroyed for the construction of coastal development, highways, shrimp farms and agriculture, threatening the prothonotary warbler’s overwintering habitat. Loss of its forest habitat in the U.S. poses a further threat to this species, with over 90 percent of the prothonotary warbler’s original breeding grounds lost to the logging and agricultural industries (5).
For the prothonotary warbler to thrive, plenty of dead tree cavities, standing water and foraging space is required. Assistance from humans, through the provision of bird houses, may also be successful in aiding this species in degraded and fragmented habitats (5).
The prothonotary warbler is a migratory species, and successful movement between habitats is dependent upon proper environmental conservation and protection. As with many other international and intercontinental conservation efforts and programs, cross-cultural cooperation and understanding are vital for success (8).
Find out more about the prothonotary warbler:
The Cornell Lab of Ornithology: All About Birds - Prothonotary warbler:
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- Genus: a category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.
- Incubate: to keep eggs warm so that development is possible.
- Isopods: a diverse group of crustaceans, with flattened, segmented bodies, that includes pill bugs and woodlice.
- Larvae: the stage in an animal’s lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
- Territorial: describes an animal, a pair of animals or a colony that occupies and defends an area.
IUCN Red List (July, 2011)
Bird Studies Canada - Prothonotary warbler (Protonotaria citrea) (July, 2011)
The Cornell Lab of Ornithology: All About Birds - Prothonotary warbler (Protonotaria citrea) (July, 2011)
Petit, L.J. (1999) Prothonotary warbler (Protonotaria citrea). In: Poole, A. (Ed.) The Birds of North America Online. Cornell Lab of Ornithology, Ithaca. Available at:
Audubon - Prothonotary warbler (Protonotaria citrea) (July, 2011)
Audubon Guides - Prothonotary warbler (Protonotaria citrea) (July, 2011)
Wisconsin All-Bird Conservation Plan - Prothonotary warbler (Protonotaria citrea) (July, 2011)
Virginia Commonwealth University Rice Center- Prothonotary warbler (Protonotaria citrea) (July, 2011)