Brown-headed cowbird
These are not the kinds of birds that are good to see in Bell Canyon. The Brown-headed cowbird is an invasive species that has an interesting approach to raising their young. Or rather not raising their young. The females will lay their eggs in the nests of other birds and abandon them to be raised by “foster parents”, often destroying at least some of the host birds own eggs and chicks in the process. Making matters worse, the baby cowbirds are larger and more persistent than their “foster siblings”, gaining them more attention from the “foster parents” which limits the chances of survival of their nest mates.
Considered a “brood parasite”, because they destroy the eggs and young of smaller birds, they have been blamed for the decline of several endangered species. To add to the problem, cowbirds can lay up to 30 eggs per season and lay 1 or 2 eggs in each host nest. That’s a lot of potential damage to our local bird populations. To protect our native species, if you see them in the canyon, please report your sighting to Invasives@wildlife.ca.gov.
Males have black bodies and brown heads. Females are plain brown, lighter on the head and underparts, with sreaking on the belly.
The song of the cowbirds is interesting scientifically. Most bird species learn their songs from other members of their species, but as cowbirds aren’t raised by members of their own species it’s interesting in that they seem to be born knowing how to communicate as a cowbird while not picking up the songs of their foster parent birds.