Return of Bird of the Week: Tricolored Blackbird


Tricolored Blackbird Male, Monterey County, California

Of the hundreds of bird species that have been described in this series of blog posts, the Tricolored Blackbird might be the species that is in the most trouble. In the 1930s, the population was two or three million birds. Populations declined from 2008 to 2011 by 35%, from 395,000 to 258,000 birds, but from 2011 to 2014 the number of birds dropped by 44%, from 258,000 to 145,000 birds. Today there are an estimated 120,000 birds left.

Tricolored Blackbird Populations, from Center for Biological Diversity’s Petition to Classify as an Endangered Species

This is a highly colonial species. That makes its colonial breeding sites susceptible to human disturbance; a single disturbance can have an immensely outsized impact. It’s a disturbingly familiar pattern; the extinct Passenger Pigeon and the Carolina Parakeet were colonial nesters, also. The State of California has classified the Tricolored Blackbird as endangered under state laws. The U.S. Fish & Wildlife Service has yet to act on the federal petition.

Another factor in the catastrophic population decline of this species is habitat loss. Tricoloreds prefer swampy areas; those have been drained for agriculture and development. When the species attempted to adjust by moving to swamp-appearing rice paddies in the Sacramento and San Joaquin Valleys, they were shot by upset rice farmers.

Tricolored Blackbird at organic dairy, with dairy cow for scale, Monterey area, California

Tricolored Blackbirds are California near-endemic, with small population in northern Mexico and southern Oregon. They are reasonably adaptable, both in terms of breeding habitat and feeding. As California’s inland marshes have vanished, the species habitats have shifted and shifted again. Recently, the breeding colonies’ shift to fields of triticale, a wheat x rye hybrid grain, especially those infested with Eurasian weeds, has been catastrophic: the fields are harvested before the young leave the nest, killing the hatchlings. The colonies, much smaller now, have now moved to dairy farms in the Central California area.

Despite considerable effort, WC was unable to find more than a very few Tricoloreds, always in mixed flocks with their Red-winged and Brewer’s cousins.

Tricolored resemble most closely their much more common Red-winged cousins. They can be distinguished by the color of their shoulder epaulets, their smaller and narrower bills and their squarish tails.

This species is pretty well studied. The causes of the catastrophic population decline are well understood. The question is whether there is the political and popular will to do anything about it.

For more bird photographs, please visit Frozen Feather Images.