Birds

June Bird Forecast | KXAN Austin

June Bird Forecast |  KXAN Austin

AUSTIN (KXAN) — Here’s Central Texas’ bird forecast for the month, courtesy of Travis Audubon. Learn more about Central Texas birds and bird-related events for all ages at travisaudubon.org or by dialing (512) 300-BIRD. follow us on Facebook as well.

Invasion of the Nest Thieves

In central Texas we have two species of cowbirds. June is a good month to search for adult and juvenile birds. Brown-headed and Bronze-headed Cowbirds lay their eggs in the nests of other songbirds, leaving these species to raise their young. This is good business for cowbirds, but problematic for the host species involved. Cowbirds do not need to build a nest, incubate eggs, and feed the young, which is physically demanding. Cowbird chicks hatch earlier, grow faster, and out-compete the host species’ chicks, which often die. It’s easy to vilify these intruders, but their reproductive biology raises some interesting questions. Since cowbirds are bred by other species, how do they know they are cowbirds? A risk of being bred by foster parents is that cowbirds may think they are the host species, learn their songs, and attempt to breed with them. Laboratory experiments confirmed this, with cowbirds bred with canaries forever confused. It turns out that young brown-headed cowbirds leave the care of their adoptive parents at night to sleep away from them in open fields, where they learn the mannerisms and songs of other cowbirds that roost there. More recent research has uncovered the area of ​​the brown-headed cowbird’s brain that is hardwired to recognize a sound that triggers the start of its journey to the cowbird’s identity. The researchers call it a chatter password, which is the sound female cowbirds make in response to potential mates and in territorial display.

Male Brown-headed Cowbird – COURTESY: James Giroux

Brown-headed cowbirds are common year-round in the Austin area (in fall and winter they congregate in large groups with other blackbirds, but in summer they disperse to breed). They used to follow the bison, not staying too long in one place, so their impact on local populations of host species was less. Once the bison left, the grain-eating cowbirds followed the cows for the insects they hunted and are now found in open areas such as parks, agricultural fields and feedlots. Habitat fragmentation caused by development and changes in land use has allowed cowbirds access to more breeding birds as their range expands. Brown-headed cowbirds have been recorded parasitizing the nests of over 220 different species of birds. These medium-sized songbirds, weighing 1.5 ounces and somewhat smaller than northern cardinals, have successfully parasitized nests of tiny blue-grey gnatcatchers (0.21 ounces), black-headed vireos (0, 3 oz.) and endangered golden cheeked warblers (. 34 oz.). If you see a songbird feeding a dull brown bird much larger than it is, you are seeing “brood parasitism” in action. Cowherds are also prolific egg producers. It is not uncommon for a female cowbird to lay 40 eggs in one season. Compare that to the four or five eggs that another songbird might have. This phenomenon also raises other questions.

Why does the host species not recognize cowbird eggs and damage or eject them? Some do, including the American robin. Why don’t they abandon the parasitized nest? Some do, such as the yellow warbler, which could also build a nest on one that contains a cowbird egg. Are cowherds horrible parents? It was thought that the female cowbirds disappeared once the egg laying was over, but it turns out that they stick around to watch over the nests. If a cowbird notices one of its eggs being ejected, it will sometimes destroy the other eggs. Some ornithologists call themcowherd mafiafor this retaliatory behavior.

Brown-headed Cowbirds all have dark eyes. Males are aptly named because they have brown heads that contrast with black bodies and wings. Females are grey-brown with a white throat – note their sneaky behavior when looking for nests. Juvenile birds are grey-brown with scaly backs and distinct streaks on the breast. Look for brown-headed cowbirds in city parks where they often roost high in trees. They will visit backyard feeders. Listen for the male’s two-note gurgle, followed by a higher-pitched “gliii”. The female has a crackling chatter.

The bronze cowbird is a southern/southwestern species that is expanding its range. It is a recent addition to the Austin landscape, where it is still rare. It overwinters in Mexico and Central America and is most noticeable here during the summer months. Golden cowbirds are slightly larger and heavier than brown-headed cowbirds and appear to target slightly larger host species. The males love display for females. Often they use a mowed area like a park or golf course, where they raise their neck, back, and body feathers, then bow, lowering their head. Sometimes they hover above the females. Males are shiny jet black with blue-black wings and red eyes. Females are duller in color but also have red eyes. Places they have been spotted recently include Emma Long Metro Park, Woodlands Park at River Place and Hornsby Bend.

Male Bronzed Cowbird – COURTESY: Jane Tillman
Bronze Cowboy Show – COURTESY: Jane Tillman

Upcoming Travis Audubon Events

Check Travis Audubon Events calendar for more details on field trips, classes and other events. Beginners are welcome for all field trips. Get outdoors with a knowledgeable leader and learn more about our beautiful Austin area birds. Most field trips fill up quickly, and most require registration.

Commons Ford Metro Park Beginner Bird Walk: Saturday, June 4, from 7:30 a.m. to 9:30 a.m. If you are beginning to take an interest in birds, this is a good place to start. If you cannot participate in this walk, mark your calendar for the first Saturday of each month and check the calendar for the location. Another birding walk at Commons Ford takes place there June 25.

North West Park: Saturday, June 18 from 7 a.m. to 9 a.m. You may be surprised at the variety of birds at this centrally located park near Shoal Creek.

There are also bird walks in West Travis County, including one at Travis Audubon. Chaetura Canyon in the Apache Shores region on June 11, and another one at Travis Audubon’s Baker Sanctuary on June 13 on Lime Creek Road. Explore Turkey Bend Recreation Area June 26.

Compiled by Travis Audubon volunteer Jane Tillman