Justification This species has experienced a long term population decline which has been rapid during the past decade. For this reason it is currently classified as Vulnerable. More accurate survey data may warrant a re-evaluation of its status.

Family/Sub-family Icteridae

Species name author (Müller, 1776)

Taxonomic source(s) AOU checklist (1998 + supplements), Cramp and Simmons (1977-1994), Sibley and Monroe (1990, 1993), Stotz et al. (1996)

Identification A medium-sized blackbird with a square-tipped tail and thick bill. Males are entirely black, faintly glossed greenish. The eye is yellow. Females are dark grey-black and lack the glossy sheen of males. Immature birds are brown with a paler supercilium, darker wings and tail and some dark barring on males. Similar spp. very similar to Brewer's Blackbird Euphagus cyanocephalus, but males of that species have a blue body gloss with contrasting violet head and females are browner. Also structurally, rusty blackbird has a finer bill and less elegant gait. Voice Males sing a squeaky but sweet rising kush-a-lee.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

200,000 - 2,000,000

decreasing

7,280,000 km²

No

Range & population Euphagus carolinus has a large range, breeding across the boreal zone of North America from New England, through Canada to Alaska and winters widely across the south-eastern United States. The population was estimated at 2 million individuals based on data from the North American Breeding Bird Survey collected during the 1980's and 1990's. This figure is now likely to be a considerable overestimate as the species continues to decline. Estimates of the global decline since 1966 vary between 85% and 99%. This ongoing decline follows a longer term decline that began prior to 1950. The reasons for this dramatic decline remain poorly understood.

Ecology: It breeds in boreal wetlands, primarily around ponds and streams within the boreal forest. It winters primarily in wooded wetlands and is not strongly associated with open agricultural habitats.

Threats The reasons behind current trends are poorly understood but hypotheses for the cause of decline include: destruction and conversion of boreal wetlands (particularly in the southern boreal forest), boreal wetland drying and chemical change resulting from global climate change, depletion of available calcium resulting from acid precipitation, increase in methyl mercury, loss of wooded wetlands in the south-east U.S. winter range, and mortality associated with past and ongoing blackbird control efforts. All of these remain possible threats.

Conservation measures underway The species is not currently listed under the United States Endangered Species Act but there is an International Rusty Blackbird Technical Group set up to research trends, threats and actions for this species.

Conservation measures proposed Continue to monitor population trends. Identify the reasons behind long-term declines. Devise suitable actions to reverse declines. Consider listing under US Endangered Species Act. Protect suitable habitat.

References Jaramillo and Burke (1999). 1. R. Greenberg in litt. (2006).

Text account compilers Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Jonathan Ekstrom (BirdLife International)

Contributors Greg Butcher (National Audubon Society), Russ Greenberg (International Heron Specialist Group), Jeff Wells (Partners in Flight)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Euphagus carolinus. Downloaded from http://www.birdlife.org on 9/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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