April bird forecast

What to watch for in April: Vocal Vireos

Here’s the 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 calling 512-300-BIRD. Follow us at www.facebook.com/travisaudubon

Peak spring bird migration in Central Texas occurs between April 22 and May 12. If you want to learn more about which birds are migrating, check out the BirdCast website. It tracks nocturnal migration across the U.S., predicts species on the move and issues high migration alerts for counties so that people can reduce outdoor lighting to minimize bird/building collisions.

While eye-dazzling spring warblers get the most attention, there’s a closely related bird family, the vireos, that has some distinctive singers. The genus has 33 species worldwide and 9 species regularly occur in Travis County. Some are eye candy too, if they deign to be seen. Learn their songs and calls to help find them. Some species favor the tree canopy while others skulk in thickets and tangles. Compared to warblers which have thin pointed bills, vireos have thicker hooked bills. They often appear stockier, with thicker necks than warblers. Some species have wingbars while others’ wings are plain.

There are two early spring arrivals to keep an ear out for.

The White-eyed Vireo is our most common vireo. The species starts arriving in Travis County in mid-March and some will stay and breed here while others head further north and east in the U.S. Most winter in Mexico and Central America although some do winter in the coastal states from Virginia to Texas (occasionally in Austin) and in the Caribbean. They are nocturnal migrants with many crossing the Gulf in both spring and fall migration.

According to the Birds of the World, both the male and female sing on the wintering grounds, but only the male sings on the breeding grounds. Males can sing while holding insects or nest material. Unpaired males prefer to sing from higher perches while mated males sing from lower perches of about 1-3 meters. Their most recognizable song is an emphatic “Quick, pick up the beer check, quick!” Overall they have at least twelve different songs. They are notable mimics, and often incorporate phrases, especially call notes, from other birds as diverse as Blue Jay, Great Crested Flycatcher, Summer Tanager, Carolina Wren and Yellow-breasted Chat all of which occur in the Austin area.

The sexes look alike. Adults have white irises, yellow “spectacles” outlining the eye, a gray head with whitish throat, greenish back, pale yellow flanks on an otherwise white breast and two white wingbars.  Young birds have dark irises, and their yellow flanks are not as pronounced.

White-eyed Vireos are monogamous with both birds helping with nest building, incubation and feeding young. Insects, some berries and even small vertebrates like lizards are on the menu with more berries taken in winter months. They glean more insects from foliage than from stems and tree branches, searching for them in a purposeful fashion. If you are lucky you may stumble across a well-hidden cup-shaped nest, often low in a deciduous shrub. It will be suspended between two horizontal branches, and is built of plant fibers, lichens, moss, bark, rootlets, and lined with spider webs. The incubating bird may be reluctant to flush and wait until the last moment to fly away; it’s best not to get too close.

White-eyed Vireos can be found in lots of different habitats such as wooded greenbelt edges and overgrown fields with brushy areas. There’s a good chance one is at your neighborhood park if it has some natural areas where greenbriar and/or grapevines ramble over woody vegetation. Many birds thrive in less maintained areas like this, which provide nesting sites and cover from predators.

Another early arrival is the Yellow-throated Vireo. It is much less common than the ubiquitous White-eyed.  It’s a shame that the Yellow-throated Vireo is more often heard than seen, as its bright yellow throat gleams! This vireo is a bird of the treetops rather than thickets and tangles. There it likes to forage on interior branches. Unfortunately, when it sings, it can be stationary for long periods of time. Be patient, watch for motion and try to locate its song. The typical song is a two note burry phrase like “three up, three down” repeated. If you get lucky and see one at Commons Ford Ranch or Emma Long Metro Parks where they are often heard, look for the yellow spectacles, two white wing bars, yellow throat which extends into the breast, white belly, and yellow-green back. Some will stay and breed in Texas, but much of the population will head to the east, northeast and central U.S. with peak migration from early April through mid-May. They prefer deciduous forests and forest edges, but some use mixed deciduous/coniferous forests.

Males arrive a few days before females, and assess possible nesting sites, then mark them with a few pieces of plant materials. Then the female decides. The male begins to build the nest, but gradually lets the female take over. The male guards the female until egg laying begins. Both incubate the eggs and raise the young. Usually there is just one brood.

Both the White-eyed Vireo and Yellow-throated Vireos are doing well across their breeding ranges. Get outside and enjoy their engaging songs.

Upcoming Travis Audubon Events – Check the events calendar for field trips and classes. Events fill quickly, and registration is required for most.

Celebrate Travis Audubon’s annual Birdathon fundraiser with free walks on Flock Party Fridays in April, at different birding hotspots in Austin: Brushy Creek, Hornsby Bend, Commons Ford Ranch and Circle Acres. Registration is needed. Learn more about other Birdathon field trip opportunities here.

Compiled by Jane Tillman, Travis Audubon Volunteer

Resources: All About Birds, Birds of the World, The Handbook of Texas Birds by Lockwood and Freeman, and The Sibley Guide to Birds by David Sibley.

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