Species Spotlight: Rusty Blackbird
Common name: Rusty Blackbird
Latin name: Euphagus carolinus
Status under the Species at Risk Public Registry (SARA): Special Concern. 2017 COSEWIC assessment: Special Concern.
Range: Breeding range includes parts of all Canadian provinces and territories, representing 70% of total range. Species migratory, overwintering throughout southeastern continental United States, and parts of southern Canada.
Lifespan: 8 years
Size: Length: 21-25 cm, Wingspan: 37 cm, Body Mass: 47-80 g
Population estimate: Canadian population estimated between 110,400 and 1.4 million individuals (~87% of total global population). The Rusty Blackbird has seen a decline of ~5.7% annually for a total of 85-90% decline since the year 1970, but short-term trends in Canada have indicated that the population has been fairly stable between 2004 and 2014.
- This medium-sized songbird is a member of the blackbird family (Icteridae), and is slightly larger but slimmer and longer than the related Red-winged Blackbird
- Plumage varies by season and sex. In winter, both sexes are rust-coloured, while during breeding season the female is brownish grey and the male is uniform black, with a faint greenish gloss on its body feather and a violet gloss on its head.
- The species features pale yellow eyes, a slightly curved bill and a rounded tail.
- Breeding sites exist primarily throughout the North American Boreal Forest. The typical breeding habitat is forested wetlands, which can include slow-moving streams and rivers, peat bogs, sedge meadows, marshes swamps and beaver ponds.
- This migratory species typically overwinters in damp woodlands and cultivated fields throughout southeastern United States, however it is regularly observed on some of the Christmas bird counts along Lake Erie in extreme Southern Ontario.
- Typically monogamous, the Rusty Blackbird nests in isolated pairs on the edges of wetlands, commonly in small conifers(specifically spruces).
- They feed mostly on invertebrates, particularly aquatic invertebrates such as insect larvae, crustaceans and snails.
- In winter, this bird joins mixed flocks with other blackbirds (eg. Grackles, Red-winged Blackbirds) and starlings, while supplementing an invertebrate-based diet with seeds and berries.
The Rusty Blackbird has exhibited an immense population crash over the past 50 years. The magnitude of this trend, based on multiple sources of long-term relative abundance data, has been estimated up to an 85% population decline since the mid-1960s.
Data derived from the Christmas Bird Count (CBC) indicated an 85% decline between 1966 and 2003, with an annual rate of decline of 5.1%. Relative abundance information derived from the North American Breeding Bird Survey (BBS) show a 6.6% annual decline between 1970 and 2011.
The Rusty Blackbird has also exhibited changes in distribution, with the species retracting approximately 143 km northward since 1966. This trend is characterized by the observation from surveys at previously occupied wetland sites in Alberta, Saskatchewan, Manitoba, and Ontario that now show less or no occupation by the species.
These population declines have not been attributed to a single source. The species faces a multitude of threats both on its breeding and wintering grounds, which likely has resulted in the cumulative effect of a massive population decline.
Initially, threats on the wintering grounds of Rusty Blackbirds were highlighted as the principal cause of the declining population. This included lethal bird control programs in agricultural cropswhich targeted mixed flocks of blackbirds and starlings. Additionally, habitat loss throughout the wintering grounds was highlighted as another culprit, as much of the lowland forests throughout the Mississippi Valley had been converted or fragmented through agricultural or urban development.
However, more recently a myriad of threats has been identified throughout the Boreal Forest breeding grounds. Recent research has suggested that industrial activity such as logging and resource extraction have resulted in the formation of wet areas that may act as “ecological traps”. They appear as suitable breeding habitats, but ultimately do not result in reproductive success. Another potential culprit of the decline is mercury contamination, as a 2010 study found that levels of mercury exposure were 3 to 7 times higher among faster-declining Rusty Blackbird populations (in Acadia) than in populations experiencing less rapid declines. Other threats within the species’ breeding range include wetland conversion and alteration, pesticide exposure, acidification and climate change.
One of the most powerful pieces of legislation protecting birds in Canada is the Migratory Birds Convention Act (MBCA), which prohibits the killing or disturbance of protected species. However, despite technically being a migratory bird, the Rusty Blackbird is not protected under this legislation. While the family Icteridae is listed under the protected families of Migratory Insectivorous Birds, there is an exemption for Icterid blackbirds and cowbirds.
What Is Being Done:
- In 2006, COSEWIC produced an assessment and status report of the Rusty Blackbird in Canada, in which the species was assessed as Special Concern. The species was re-assessed by COSEWIC in 2018, and given the same status.
- The species is listed as Special Concern under the federal Species at Risk Act. However, this designation does not actually give the species protection under the act, but rather establishes the requirement of a management plan for the species.
- Provincially, the Rusty Blackbird has been designated as Vulnerable under the Newfoundland and Labrador Endangered Species Act, as a Species of Special Concern under the Species at Risk Act of New Brunswick, and as a species Susceptible to be listed as Vulnerable or Threatened in Quebec.
- In 2015, The Government of Canada released the finalized Management Plan for the Rusty Blackbird (Euphagus carolinus) in Canada, which outlines management and research requirements to promote the recovery of the species.
- There is a large amount of research on trends and threats affecting the species. For more information, see the 2015 management plan.
- The International Rusty Blackbird Working Group was founded in 2005 to foster communication among researchers studying the decline of the species, and is currently developing an international conservation strategy for the species, and also orchestrated a citizen science migration blitz to better document rusty blackbird migration.
What You Can Do:
- Get birding. Get outside, explore your local avifauna, and log your sightings on eBird
- Participate in during your local Christmas Bird Count.
- If you are an experienced birder, you can participate in the North American Breeding Bird Survey, to help gather more occurrence data for this species, which will help establish long-term trends for the rusty blackbird and other bird species.
- Contact your local Bird Banding Association, and contribute to this valuable science.
- Write your MP, and tell them how the protection of our imperiled species is important to you.
- Committee on the Status of Endangered Wildlife in Canada (COSEWIC)
- Species at Risk Public Registry (SARA)
This profile was written by Sean Feagan.