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blue-winged warbler

Vermivora pinus

What do they look like?

Male and female blue-winged warblers are the same color, although females tend to be drabber. Their forehead, crown, chin, throat, breast, flanks and belly are bright yellow year round. Their wing coverts are blue-grey with white bars on their tail and flight feathers, although females tend to have thinner white bars. The color of their bill changes seasonally for males, it is black in spring and summer, and pinkish to light brown in the fall and winter. Blue-winged warblers can be identified by the black stripe through their eye and white wing bars. Towards the end of the breeding season, typically late June to early August, adults molt. As adults, blue-winged warblers weigh between 7.9 to 10.5 g and they measure 11.4 to 12.7 cm in length. Their wingspan is usually about 17.15 cm. (Dunn and Garrett, 1997; Gill, et al., 2013; Mertz, 2004; Morris, et al., 1996; Reynolds and Lee III, 1996; Terres, 1980)

  • Sexual Dimorphism
  • sexes colored or patterned differently
  • male more colorful
  • Range mass
    7.9 to 10.5 g
    0.28 to 0.37 oz
  • Range length
    11.4 to 12.7 cm
    4.49 to 5.00 in
  • Average length
    12 cm
    4.72 in
  • Average wingspan
    17.15 cm
    6.75 in

Where do they live?

Blue-winged warblers (Vermivora pinus) are native to North America and migrate between North and South America. During their breeding season, they can be found in the Midwest, as well as the northeastern and southeastern United States, as far west as Nebraska and as far south as northern Georgia and northern Alabama. More recently, their range has expanded further north, to southern Maine. During the winter, they migrate south, where they can be found in Mexico, throughout Central America, and northern Colombia. While their wintering range seems large, they are mostly found between Honduras and the Yucatán Peninsula. Their North American range is steadily expanding northward. Populations reached Ohio in the early 1900s, Michigan by the 1920s, and New York between 1950 to 1971. (American Ornithologists' Union, 1957; Confer and Tupper, 2000; Gill, 2004; Gill, et al., 2013; Harrison, 1984; Hitch and Leberg, 2007; Koonce, 2005; Price, 2008)

What kind of habitat do they need?

Blue-winged warblers live in wetlands, shrublands, and forests, usually in lower elevations areas. They breed in clearings, fields, and stream edges that have weedy and brushy undergrowth. They can also be found in lower elevation areas of the Appalachian Mountains (less than 609.6 m). They are found in similar areas during the winter, in low elevation areas of foothills, overgrown fields, and mixed forests. (Confer, et al., 2010; Dettmers, 2003; Dunn and Garrett, 1997; Gill, et al., 2013; Harrison, 1984)

  • Aquatic Biomes
  • rivers and streams
  • Range elevation
    <304.8 to 609.6 m
    to 2000.00 ft

How do they reproduce?

Blue-winged warblers begin bonding in a pair within a week of arrival at the breeding grounds. This process involves the male chasing a female, who may or may not choose to mate with him. When a female chooses a mate, she responds to his chase by making “tzip” calls. Bonded pairs may peck at each other or duel with their bills. These birds are monogamous, meaning they usually only mate within their pair, however, other songbird species are known to sometimes mate outside of their pair, this may also be true of blue-winged warblers. (Ficken and Ficken, 1968a; Gill, et al., 2013)

On average, blue-winged warblers arrive at their breeding grounds during the first week of May, although as temperatures increase, they have been arriving even earlier. After forming a pair bond, the female begins building a nest, using thick grass to form a deep, cup-shaped nest supported by dead leaves. The nest is usually completed in about 2 to 4 days. Their nests are found close to the ground and blends in well with their surroundings. Their eggs are speckled with grey or brown spots against their white color. The female lays 1 egg per day for 3 to 5 days, and incubates them for about 10 to 12 days. While incubating, females spend most of their time sitting on the eggs, keeping them warm and leaving only to feed. Upon hatching, nestlings weigh, on average, 1.5 g. The nestling stage lasts 8 to 10 days, until nestlings fledge. During the nestling stage, both the male and female spend more time foraging, and bring food to the nest to feed the nestlings. After fledging, the female and male continue to bring food to the young, who tend to stay within 100 m of the nest for 2 to 5 days. These birds usually fledge in late May or early June. Blue-winged warblers occasionally breed with golden-winged warblers and have hybrid offspring known as Brewster’s warblers, which may also interbreed with other hybrids, giving rise to Lawrence’s warblers. (Butler, 2003; Gill, et al., 2013; Harrison, 1984; Marra, et al., 2005; Mertz, 2004; Patton, et al., 2010)

  • How often does reproduction occur?
    Blue-winged warblers produce 1 clutch of eggs yearly.
  • Breeding season
    Blue-winged warblers begin breeding the first week of May and end in early to mid-June.
  • Range eggs per season
    2 to 7
  • Average eggs per season
    5
  • Range time to hatching
    10 to 12 days
  • Range fledging age
    8 to 10 days
  • Average age at sexual or reproductive maturity (female)
    1 years
  • Average age at sexual or reproductive maturity (male)
    1 years

While building the nest, females are likely to abandon a partial nest if they are disturbed by a predator or intruder. While incubating the eggs, females infrequently leave the nest. During the nestling stage, both parents spend time feeding and keeping the nest clean by removing fecal pellets, which they pick up and carry out of the nest with their beaks. (Gill, et al., 2013; Harrison, 1984)

How long do they live?

There are very few studies on the lifespan of blue-winged warblers. Banded birds that have been recaptured have survived up to 7 and 9 years, although that is an unusually long lifespan in the wild. On average, blue-winged warblers live about 2.5 years in the wild. (Gill, et al., 2013; Klimkiewicz, et al., 1983; United States Geological Society, 2013)

  • Range lifespan
    Status: wild
    9 (high) years
  • Average lifespan
    Status: wild
    2.5 years

How do they behave?

Blue-winged warblers may have different types of interactions with other members of their species depending on the time of year, their gender, and the type of encounter. During the breeding season, they are aggressive towards others on their mating ground. When an intruder enters their territory, they respond with displays of tail-spreading and crown-raising. They may also chase, fly past, and physically fight the intruder. Encounters like these may last seconds or several minutes, depending on how fast the intruder leaves. Aggressive encounters are most common during the first week of arrival at breeding grounds, when males are competing for mates and territory. When blue-winged warblers are on the ground foraging, they move by hopping. They perch on branches near their nest during the breeding season, and occasionally hang upside down as they explore new areas. Both sexes preen their feathers, which takes about 2 to 5% of their time. During the winter, most wood warblers, like blue-winged warblers, live in small groups and sometimes separate into groups of males and females. (Dunn and Garrett, 1997)

  • Range territory size
    0.0013 to 0.02 km^2

Home Range

Depending on how many birds there are at the breeding ground, an individual may have a territory range of 0.13 to 2 hectares. During the breeding season, neither the male or female stray far from their territory, they usually remain within 100 m of the nest. (Gill, et al., 2013)

How do they communicate with each other?

Blue-winged warblers sing two distinct songs that sound more insect-like than bird-like. Type I songs are sung by males, mostly during the first few weeks of the breeding season when they are not paired. It is a simple “bee-bzzz,” and lasts about 1.1 to 1.9 seconds. Type II songs are used throughout the breeding season, but are most common during egg-laying and incubation phases. Type II songs are more variable and there are different dialects of the song in different geographic locations. Males mostly use type II songs when they interact with other males, often to declare their territory. Type II songs are not unique to blue-winged warblers. Golden-winged warblers and hybrids sing nearly identical songs. Female and male call notes are described as “tzip” or “tsik”. (Dunn and Garrett, 1997; Ficken and Ficken, 1968b; Ficken and Ficken, 1969; Harrison, 1984; Kroodsma, et al., 1984; Kroodsma, 1988; Morse, 1989)

What do they eat?

Blue-winged warblers forage for small insects and vegetation in their habitat. Their beak is longer than other wood warblers, which allows them to search through and open clusters of leaves to better find the food that could be inside. During the incubation period, males spend more time foraging because females are mostly unable to forage for themselves. (Dunn and Garrett, 1997; Gill, et al., 2013; Mertz, 2004)

  • Animal Foods
  • insects
  • terrestrial worms
  • Plant Foods
  • seeds, grains, and nuts

What eats them and how do they avoid being eaten?

Eggs and nestlings are often preyed on because the nests are near the ground. Small animals such as chipmunks, raccoons, opossums, water snakes and black snakes often remove eggs or nestlings from the nests. Larger birds such as blue jays, American crows and hawks are more common predators of adult blue-winged warblers, though small mammals may also prey upon adults. (Clark and Robertson, 1979; Coker and Confer, 1990; Gill, et al., 2013; McAtee, 1938; Mertz, 2004)

What roles do they have in the ecosystem?

As with many bird species, nestlings are prone to ectoparasites. Larvae of avian blowflies, chigger mites, and fowl mites attach and feed from young while they are in the nest, though this does not often directly kill the nestlings. Instead, blood loss leaves the nestlings nutrient poor and with a weak immune system. This can result in a longer time to fledging and make them more vulnerable to other diseases or predation. Blue-winged warblers participate in "anting," where they "bathe" in ant nests or place ants under their feathers. Some ant species secrete a liquid that contains formic acid, which covers the bird and may act as an insecticide. Brown-headed cowbirds are a brood parasite, which means they lay their eggs in the nests of other species, including blue-winged warblers. As a result, blue-winged warblers feed the brown-headed cowbird nestlings with their own, although brown-headed cowbird nestlings are larger than blue-winged warbler nestlings and outcompete them for food. ("A comparison of ectoparasite infection by chigger mite larvae (Acarina: Trombiculidae) on resident and migratory birds in Chiapas, Mexico illustrating a rapid visual assessment protocol", 2005; Clark and Robertson, 1979; Coker and Confer, 1990; Gill, et al., 2013; Grube, 1953; McAtee, 1938; Mertz, 2004)

Commensal or parasitic species (or larger taxonomic groups) that use this species as a host

Do they cause problems?

There are no negative effects of blue-winged warblers on humans.

How do they interact with us?

Blue-winged warblers are tolerant of human activity near their nesting sites, which makes them an easily spotted species for avid bird watchers. Bird watching is a big source of ecotourism, some cities host bird watching festivals, a tourist attraction that can make money and create interest for future visits. Throughout the United States in 2006, about $82.2 billion was spent on birding, with $23.7 billion spent on equipment alone. ("Louisiana bird watchers: a further examination of past research", 2010; Gill, et al., 2013)

  • Ways that people benefit from these animals:
  • ecotourism

Are they endangered?

Blue-winged warblers are a species of least concern according to the IUCN Red List and do not have special status on US government lists. While their population is declining, it is not at a rate that would qualify the species as vulnerable. Recently, these birds have been moving further northward, which has caused their territories to overlap with golden-winged warblers, creating hybrid areas with hybrid species, Brewster's and Lawrence's warblers. As more hybrid areas are created, blue-winged warblers may replace golden-winged warblers within 4 to 50 years. (Confer, et al., 2010; Gill, et al., 2013)

Some more information...

Contributors

Fionna Surette (author), Radford University, Karen Powers (editor), Radford University, Leila Siciliano Martina (editor), Animal Diversity Web Staff.

References

USDA Forest Service. A comparison of ectoparasite infection by chigger mite larvae (Acarina: Trombiculidae) on resident and migratory birds in Chiapas, Mexico illustrating a rapid visual assessment protocol. PSW-GTR-191.2005. California: USDA. 2005.

Louisiana Department of Wildlife and Fisheries. Louisiana bird watchers: a further examination of past research. Not listed. Baton Rouge, LA: Louisiana Department of Wildlife and Fisheries. 2010. Accessed November 18, 2013 at http://www.wlf.louisiana.gov/sites/default/files/pdf/document/33317-louisiana-bird-watchers-further-examination-past-research/louisiana-birders-further-examination.pdf.

American Ornithologists' Union, 1957. The A.O.U. Check-list of North American Birds. not listed: American Ornithologists' Union.

Butler, C. 2003. The disproportionate effect of global warming on the arrival dates of short-distance migratory birds in North America. Ibis, 145: 484-495.

Chesser, R., R. Banks, F. Barker, C. Cicero, J. Dunn, A. Kratter, I. Lovette, P. Rasmussen, J. Remsen, J. Rising, D. Stotz, K. Winkerm. 2010. Fifty-first supplement to the American Ornithologists' Union check-list of North American birds. The Auk, 127/3: 726-744.

Clark, K., R. Robertson. 1979. Spatial and temporal multi-species nesting aggregations in birds as anti-parasite and anti-predator defenses. Behavioral Ecology and Sociobiology, 5/4: 359-371.

Coker, D., J. Confer. 1990. Brown-Headed cowbird parasitism on golden-winged and blue-winged warblers. The Wilson Bulletin, 102/3: 550-552.

Confer, J., K. Barnes, E. Alvey. 2010. Golden- and blue- winged warblers: distribution, nesting success, and genetic differences in two habitats. The Wilson Journal of Ornithology, 122/2: 273-278.

Confer, J., S. Tupper. 2000. A reassessment of the status of golden-winged and blue-winged warblers in the Hudson Highlands of southern New York. The Wilson Bulletin, 112/4: 544-546.

Dettmers, R. 2003. Status and conservation of shrubland birds in the northeastern US. Forest Ecology and Management, 185: 81-93.

Dunn, J., K. Garrett. 1997. A Field Guide to Warblers of North America. New York, NY: Houghton Mifflin Company.

Ficken, M., R. Ficken. 1968. Courtship of blue-winged warblers, golden-winged warblers, and their hybrids. The Wilson Bulletin, 80/2: 161-172.

Ficken, M., R. Ficken. 1968. Reproductive isolating mechanisms in the blue-winged warbler-golden-winged warbler complex. Evolution, 22/1: 166-179.

Ficken, M., R. Ficken. 1969. Responses of blue-winged warblers and golden-winged warblers to their own and the other species' song. The Wilson Bulletin, 81: 69-74.

Gill, F. 2004. Blue-winged warblers (Vermivora pinus) versus golden-winged warblers (V. chrysoptera). The Auk, 121/4: 1014-1018.

Gill, F., R. Canterbury, J. Confer. 2013. "The Birds of North America" (On-line). Accessed September 08, 2013 at http://bna.birds.cornell.edu/bna/species/584/articles/introduction.

Grube, G. 1953. Black snake captures nestling blue-winged warbler. Wilson Bulletin, 65/1: 50.

Harrison, H. 1984. Wood Warblers' World. New York, NY: Simon and Schuster.

Hitch, A., P. Leberg. 2007. Breeding distributions of North American bird species moving north as a result of climate change. Conservation Biology, 21/2: 534-539.

Klimkiewicz, K., R. Clapp, A. Futcher. 1983. Longevity records of North American birds: Remizidae through Parulinae. Journal of Field Ornithology, 54/3: 287-294.

Koonce, A. 2005. The role of juvenile dispersal in the replacement of golden-winged warblers by blue-winged warblers. Natural Resource Modeling, 18/4: 537-547.

Kroodsma, D. 1988. Song types and their use: developmental flexibility of the male blue-winged warbler. Ethology, 79/3: 235-247.

Kroodsma, D., W. Meservey, A. Whitlock, W. VanderHaegen. 1984. Blue-winged warblers (Vermivora pinus) "recognize" dialects in type II but not type I songs. Behavioral Ecology and Sociobiology, 15/2: 127-131.

Marra, P., C. Francis, R. Mulvihill, F. Moore. 2005. The influence of climate on the timing and rate of spring bird migration. Oecologia, 142: 307-315.

McAtee, W. 1938. 'Anting' by birds. The Auk, 55/1: 98-108.

Mertz, L. 2004. New World Warblers (Parulidae). Pp. 285-300 in M Hutchins, A Evans, J Jackson, D Kleiman, J Murphy, eds. Grzimek's Animal Life Encyclopedia, Vol. 11/2. Detroit: Gale.

Morris, S., D. Holmes, M. Richmond. 1996. A ten-year study of the stopover patterns of migratory passerines during fall migration on Appledore Island, Maine. The Condor, 98/2: 395-409.

Morse, D. 1989. American Warblers. United States of America: Harvard University Press.

Patton, L., D. Maehr, J. Duchamp, S. Fei, J. Gassett, J. Larkin. 2010. Do the golden-winged warbler and blue-winged warbler exhibit species-specific differences in their breeding habitat use?. Avian Conservation and Ecology, 5/2: 2-21.

Price, T. 2008. Speciation in Birds. Greenwood Village: Roberts and Company Publishers.

Reynolds, P., R. Lee III. 1996. Phylogenetic analysis of avian energetics: Passerines and nonpasserines do not differ. Chicago Journals, 147/5: 735-759.

Terres, J. 1980. The Audubon Society Encyclopedia of North American Birds. New York: Alfred A. Knopf, Inc.

United States Geological Society, 2013. "Longevity Records of North American Birds" (On-line). Accessed October 25, 2013 at http://www.pwrc.usgs.gov/bbl/longevity/Longevity_main.cfm.

 
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Surette, F. 2014. "Vermivora pinus" (On-line), Animal Diversity Web. Accessed September 21, 2018 at http://www.biokids.umich.edu/accounts/Vermivora_pinus/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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