The upper tail and back are an olive-brown color, with the underside of the tail having white feathers. Both male and female birds have a black face with yellow around the eyes, but the coloring on the male is more drastic and distinctive compared to the shaded colors of the female. Wilsonia citrina also has yellow on the underside of the body and pink legs. (Robbins, et al., 1966)
Wilsonia citrina is generally found in the midwestern and eastern parts of the United States. The western boundary extends north from east Texas to central Wisconsin, and on the east can be found from western New York and Connecticut down to northern Florida. The hooded warbler generally migrates to Southern Mexico and Central America for the winters. (Johns, 2000)
Wilsonia citrina generally nests in gaps in heavily forested areas, but stays away from the edge of the forest. Wilsonia citrina picks sites that have a well developed understory to build the nest in. The male and female prefer different habitats during the winter months. Males still prefer forested areas while females will take up in brushy fields and shrubby areas (Johns, 2000).
Both male and female W. citrina sing during the process of attracting a mate. While birds will form pairs for mating purposes, it is frequently found that a mother's eggs have been fertilized by a neighboring male (Johns, 2000).
The female constructs a nest in the underbrush of a low lying area. The nest is constructed of bark and plant material, with an outer layer of dead leaves. Three to five eggs are laid, then normally incubated for about twelve days before hatching. After hatching, the chicks will fledge in about eight or nine days and continue their growth into adult birds. Juvenile birds will be capable of reproduction the next breeding season.
Males provide from 25% to 75% of feeding visits to young. Scientists had hypothesized that males that provide less parental care use their time and energy to seek matings with neighboring females instead. However, this turns out not to be the case. (Pitcher and Stutchbury, 2000)
The lifespan of W. citrina is about 8-9 years.
Wilsonia citrina is a migratory bird that summers in North America and migrates south nocturnally to Mexico and Cenral America for the winters. While wintering, the male and female birds often live in different habitats - the males in forests and the females in shrubbery. It is thought that this may have something to do with the sexual dominance of the male (Johns, 2000). While most males attract a single mate, some males will have two females on their territory. Hooded Warblers may avoid small areas of woods in order to increase the number of territories, and thus the chance of inter-pair fertilization.
The hooded warbler has two modes of singing. One involves repeatedly singing the same pattern, and the other is an irregular mix of 3 or 4 different patterns. Singing is used by both the males and females in attracting mates. The repeat mode may be used for attracting the mate, while the irregular mode is some sort of method of "negotiating" with nearby warblers (Wiley, et al., 1994).
Wilsonia citrina feeds primarily on small insects, spiders and other arthropods, either catching them while in flight or picking them off of forest vegetation (Johns, 2000).
Predators of W. citrina include snakes, racoons and cats. The largest danger comes from the possibility of running into man-made structures during the nocturnal migrations (Whittam & McCracken, 1999).
While this species feeds on small insects and arthropods, it is not clear that it plays a unique role in the ecosystem, or that its function would have any impact on the ecosystem if it were removed. It has been reduced dramatically in number in various Canadian forests, but there is no apparent effect on those forests (Whittam & McCracken, 1999).
This species has no negative effect on humans.
It is not clear that this species has any positive impact on humans other than its aesthetic value and its contribution to animal diversity.
Wilsonia citrina is generally abundant in the United States. In Canada, however, concern has been raised about the dwindling number of mating pairs and efforts are being made to study and prevent the loss of this species from the Canadian landscape. In some cases selective logging may actually help in that it provides a gap in the forest for W. citrina to live, yet doesn't create an edge to the forest. It is difficult for W. citrina to survive on the forest edge because of the increased presence of predators and the loss of desired habitat. (Whittam & McCracken, 1999). Hooded warblers are considered to be a species of special concern in Michigan.
Charles Vance (author), University of Michigan-Ann Arbor, Kerry Yurewicz (editor), University of Michigan-Ann Arbor.
June 1, 2000. "Georgia Wildlife Web Site; birds: Wilsonia citrina" (On-line). Accessed April 7, 2002 at http://museum.nhm.uga.edu/gawildlife/birds/passeriformes/wcitrina.html.
"Warbler Watch: Hooded Warbler" (On-line). Accessed March 22, 2002 at http://birdsource.cornell.edu/warblers/species/hoowar/.
Johns, M. 2000. "Hooded Warbler" (On-line). Accessed March 22, 2002 at http://faculty.ncwc.edu/MBrooks/pif/Bird%20Profiles/hooded_warbler.htm.
Patuxent Wildlife Research Center, "Hooded warbler identification tips" (On-line). Accessed April 7, 2002 at http://www.mbr-pwrc.usgs.gov/id/framlst/Idtips/h6840id.html.
Pitcher, T., B. Stutchbury. 2000. Extraterritorial forays and male parental care in hooded warblers. Animal Behaviour, 59: 1261-1269.
Robbins, C., B. Bruun, H. Zim. 1966. Birds of North America. New York, NY: Western Publishing Company, Inc..
Whittam, B., J. McCracken. 1999. "Bird Studies Canada report: Hooded warbler poductivity and habitat selection in southern Ontario" (On-line). Accessed 20 June 2003 at http://www.bsc-eoc.org/download/howareport.pdf.
Wiley, R., R. Goddard, A. Thompson. 1994. Use of two singing modes by hooded warblers as adaptations for signalling. Behaviour, 129: 57-75.