Brewer's blackbird
Male in Esquimalt Lagoon Migratory Bird Sanctuary, British Columbia
Female in San Luis Obispo, California
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Icteridae
Genus: Euphagus
Species:
E. cyanocephalus
Binomial name
Euphagus cyanocephalus
(Wagler, 1829)
Range of E. cyanocephalus
  Breeding range
  Year-round range
  Wintering range
Synonyms

Euphagus affinis (Shufeldt, 1892)

Brewer's blackbird (Euphagus cyanocephalus) is a medium-sized New World blackbird. It is named after the ornithologist Thomas Mayo Brewer.

Description

Adult males have black plumage with an iridescent purple head and neck and glossy bluish-green highlights on the rest of the body. The feet and legs are black and the eye is bright yellow. The female is brownish-grey with slight hints of the male's iridescence. The female's eye is dark brown, while the male's is bright yellow. Overall, they resemble the eastern member of the same genus, the rusty blackbird; Brewer's blackbird, however, has a shorter bill and the male's head is iridescent purple.[2] This bird is often mistaken for the common grackle but has a shorter tail. The call is a sharp check which is also distinguishable. This bird is in a different family from the Eurasian blackbird.

Standard Measurements[3][4]
length8–10.3 in (200–260 mm)
weight63 g (2.2 oz)
wingspan15.5 in (390 mm)
wing121–133 mm (4.8–5.2 in)
tail95–102.5 mm (3.74–4.04 in)
culmen20.4–24 mm (0.80–0.94 in)
tarsus29.5–33.5 mm (1.16–1.32 in)

Habitat

Their breeding habitat is open and semi-open areas, often near water, across central and western North America. They are also very common in parking lots or around schools, and easily acclimate to the presence of people.[5] They can live in low elevation, as low as below sea level in Southern California, and elevation as high as 8,000 feet. They are capable of surviving in diverse environments, including marshlands and forests. [6]

These birds are often permanent residents in the west. Other birds migrate to the Southeastern United States and Mexico in Spring. The range of this bird has been expanding east in the Great Lakes region.[7][5] They've expanded their habitat as recently as the 20th century.[5]

Behavior

When Brewer’s Blackbirds identify threats, such as hawks or even humans, they dive towards them and omit an alarm call. Sometimes, when particularly threatened, they will use physical force on predators.[6]

Brewer’s Blackbirds often walk along the ground. They can be seen making jerking motions with their heads. In colder months, these birds tend to flock together and forage. Sometimes, other species of blackbirds will join these flocks. During nesting season, their foraging behavior becomes more independent. Brewer’s Blackbirds have been seen cleverly following vehicles plowing fields, eating the churned up insects.[5]

Feeding

They forage in shallow water or in fields, mainly eating seeds and insects, some berries. They sometimes catch insects in flight. They feed in flocks outside of the breeding season, sometimes with other blackbirds.[5] In marshy areas, they are known to stand on aquatic plants and wade in shallow water to catch insects. Some have even been known to eat smaller mammals, amphibians, and the nestlings of other birds.[6][5]

Reproduction

These birds have mates but the mates don't stay together all year round. The same pair tends to reunite for mating season[6] and both parents take a role in feeding.[5] During mating, male Brewer’s Blackbirds will puff up their feathers while simultaneously spreading out their wings and tail to look as large as possible. They’ll point their beak out forward.[5] Their clutch size can vary, usually between 3–7.[5] Eggs are usually a tan color with darker speckles throughout to allow for camouflage.[8] The female bird primarily incubates for 12–14 days.[5] The chicks leave the nest only 2 weeks after hatching.[5]

Nests are not built in isolation, but in colonies of up to 30 pairs.[5] Pairs prefer to nest in areas that are around 20–40' in treetops. However, colonies that live near water may also nest in reeds and other freshwater plants.[6] Nests are made from nearby material such as reeds, sticks and hair. They are built by the female in a cup-like shape and are bonded with mud or other securing substances.[6] The color of the nest usually matches the coloration of the eggs and the surrounding environment as it is crucial to survival.[9] Brewer's Blackbird chicks do not immediately open their eyes upon hatching and do not hatch with feathers.[6]

Protected status

Brewer's blackbird (Euphagus cyanocephalus) is protected in the United States under the Migratory Bird Treaty Act of 1918,[10] however exceptions are granted under 50 CFR part 21 (2014) [11] for animals committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock, or wildlife, or when concentrated in such numbers and manner that they are a health hazard or other nuisance. They are moderately threatened by climate change. However, this could change if temperatures continue to rise. If temperatures rise by 3 degrees celsius, they could lose 30% of their range. Heat and wildfires are particularly threatening.[5] Their numbers have dropped 57% from 1966-2019.[12] It is estimated that there are currently 23 million Brewer's blackbirds in the wild.[13]

References

  1. ↑ BirdLife International (2016). "Euphagus cyanocephalus". IUCN Red List of Threatened Species. 2016: e.T22724332A94861418. doi:10.2305/IUCN.UK.2016-3.RLTS.T22724332A94861418.en. Retrieved 13 November 2021.
  2. ↑ Peterson, Roger Tory; Peterson, Virginia Marie (2002). Birds of Eastern and Central North America (5th ed.). New York, NY: Houghton Mifflin. p. 310. ISBN 0-395-74047-9.
  3. ↑ Godfrey, W. Earl (1966). The Birds of Canada. Ottawa: National Museum of Canada. p. 359.
  4. ↑ Sibley, David Allen (2000). The Sibley Guide to Birds. New York: Knopf. p. 514. ISBN 0-679-45122-6.
  5. 1 2 3 4 5 6 7 8 9 10 11 12 13 "Brewer's Blackbird". Audubon. 13 November 2014. Retrieved 23 October 2022.
  6. 1 2 3 4 5 6 7 "Brewer's Blackbird Life History, All About Birds, Cornell Lab of Ornithology". www.allaboutbirds.org. Retrieved 23 October 2023.
  7. ↑ Stepney, P.H.R.; Power, Dennis M. (December 1973). "Analysis of the Eastward Breeding Expansion of Brewer's Blackbird Plus General Aspects of Avian Expansions" (PDF). The Wilson Bulletin. 85 (4): 452–464.
  8. ↑ Balph, Martha Hatch (1975). "Development of Young Brewer's Blackbirds". The Wilson Bulletin. 87 (2): 207–230. ISSN 0043-5643. JSTOR 4160619.
  9. ↑ Westmoreland, David; A. Kiltie, Richard (November 2007). "Egg coloration and selection for crypsis in open-nesting blackbirds". Journal of Avian Biology. 38 (6): 682–689. doi:10.1111/j.2007.0908-8857.04066.x.
  10. ↑ "List of Migratory Bird Species Protected by the Migratory Bird Treaty Act as of December 2, 2013". US Fish & Wildlife Service.
  11. ↑ "Migratory Bird Permits; Removal of Yellow-billed Magpie and Other Revisions to Depredation Order" (PDF). Federal Register. 79 (214): 65595–65602. Archived from the original (PDF) on 18 July 2017. Retrieved 17 May 2018.
  12. ↑ "BBS - About - USGS Patuxent Wildlife Research Center". www.pwrc.usgs.gov. Retrieved 23 October 2023.
  13. ↑ "Avian Conservation Assessment Database Scores – Partners in Flight Databases". Retrieved 23 October 2023.
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