A Saturday
Night Live skit humorously suggested adding more cowbells to a song that the
band was playing. However, considering the behavior of Brown-headed Cowbirds,
we certainly do not need more of them at Carillon Stonegate Pond!
Identification:
Brown head!
And the subtle brown head sits atop the adult male’s glossy black plumage. The
female Brown-headed Cowbird is plain brown with the head and underparts lighter
in tone. The Brown-headed Cowbird’s bill has a distinctive shape. It is much
shorter and thicker-based than other blackbirds', almost finch-like at first
glance. The male Brown-headed Cowbird averages eight (8) inches in length. And
their wingspan is 14 inches. They weigh in at only around 1 ¾ ounces. The
smaller female Brown-headed Cowbird averages 7 ½ inches in length. And their
wingspan is 12 inches. They weigh in at less than 1 ½ ounces.
Habitat at
Carillon Stonegate Pond? Brown-headed Cowbirds arrive here in early
April and stay through the start of autumn. Look in the skies over the fields
and woods around our ponds. They also like to eat at our feeders and on the
ground in our yards.
Flight
patterns: There is nothing distinctive in the flight patterns of
Brown-headed Cowbirds during breeding season. However, after breeding season,
these birds tend to congregate in large flocks with other blackbirds, including
Red-winged Blackbirds. And they will move in swarms from their roosting areas
to their feeding areas in the mornings and retrace this path in the late
afternoons.
Behavior: The
Brown-headed Cowbird has a fascinating approach to raising its young – they
do not! Females forgo building nests. Instead, they put all their
energy into producing eggs, sometimes more than several dozen a summer. The
female lays one egg in the nest of another bird. Essentially abandoning their
young to foster parents, usually at the expense of at least some of the host’s
own chicks.
Diet: Brown-headed
Cowbirds feed mostly on seeds from grasses and weeds, with some crop grains.
Insects such as grasshoppers and beetles make up about a quarter of a cowbird’s
diet, often are caught as cows and horses stir them into movement.
Residence: Brown-headed
Cowbirds are native to North America and may be found in fields, meadows, and
lawns across most of the U.S. It lives in all habitats but is especially often
found in forest edges.
Breeding
and Nesting: Brown-headed Cowbirds breed from British Columbia,
central Saskatchewan, central Ontario, Quebec, and Newfoundland southward
throughout United States except extreme Southeast and Florida. Brown-headed
Cowbirds are brood parasites and promiscuous; no pair bond
exists. In late spring the female cowbird and several suitors move into the
woods. The males sit upright on treetops, uttering sharp whistles, while the
female searches for nests in which to lay her eggs. Upon choosing a nest, she
removes one egg of the host's clutch, and deposits one of her own in its place.
Migration: The
Brown‐headed
Cowbird is a common migrant and summer resident throughout Illinois and a
common winter resident in southern Illinois. Spring migrants begin arriving in
Illinois in February. They may begin to depart from nesting areas by August or
even July.
Conservation status: There is low concern. According to the North American Breeding Bird Survey, the Brown-headed Cowbird has seen slight decreases in populations. Partners in Flight estimates the global breeding population at 130 million.
Vocalizations: Brown-headed
Cowbirds are noisy, making a multitude of clicks, whistles and chatter-like
calls in addition to a flowing, gurgling song. Here is a link to the sounds of the Brown-headed
Cowbird.
Interesting
Facts:
- The Brown-headed Cowbird is North
America’s most common “brood parasite” - lays her eggs in the nests of
other bird species, who then raise the young cowbirds.
- Male and female Brown-headed
Cowbirds are not monogamous and have several different mates within a
single season.
- Brown-headed Cowbird lay eggs in
the nests of more than 220 species of birds.
- In winter, Brown-headed Cowbirds
may join huge roosts with several blackbird species - one such mixed roost
contained more than five million birds.
- The oldest recorded Brown-headed
Cowbird was approximately 17 years old.
For more information on Brown-headed Cowbirds and sources of information used in this blog (these are the sources that I am using to learn as I blog), please visit All About Birds, the Audubon Society and National Geographic. And the Cornell Lab of Ornithology provides a wonderful source of information for anyone interested in learning more about birds.
We all benefit
from the variety of wetland, forest, and prairie environments that support
diverse wildlife, plants, and insects of Carillon Stonegate Pond.
Take
a hike and see what you can find – and identify!
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