What to watch for in April – Zugunruhe
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
April is the big month for bird migration when birds leave their wintering grounds for their breeding grounds. It’s time to get outdoors and witness this semiannual event for yourself!
What triggers migration? According to All About Birds of the Cornell Lab of Ornithology several factors come into play, including changes in day length, temperature changes, birds’ genetic makeup, and changes in food resources.
Neotropical birds wintering down in Central and South America begin to experience nocturnal migratory restlessness prior to their journeys north. This phenomenon, Zugunruhe, was named by Gustav Kramer in 1949. He studied caged migratory birds under the night sky and found that they generally oriented themselves in the direction of predicted migration. How birds manage to navigate to a location that might be within a mile of where they were born is not completely understood. They can sense the earth’s magnetic field, and pay attention to celestial cues and the position of the setting sun and physical landmarks. Some birds may even use their sense of smell, which is suspected in homing pigeons.
Bird watchers experience a form of Zugunruhe too — a restlessness to get outside, shirk work and head to a coastal hotspot like High Island, east of Houston, to enjoy the thrill of colorful warblers, thrushes, vireos and other songbirds arriving after a long overnight flight from the Yucatan. A visit to a migratory hotspot like High Island, Sabine Woods by Beaumont, or Rockport should be on every nature lover’s to-do list.
Not all birds make the trans-Gulf hop, instead opting for a circum-Gulf route. That includes both Broad-winged and Swainson’s Hawks, which pass through central Texas in April in large numbers. Unfortunately they are generally silent so that sixth sense will have to be at work to get you to look up and sight a kettle of them spiraling upwards. Wait and watch them glide downwards to catch the next thermal. They will repeat this roller coaster motion of kettling and gliding on fixed wings to save energy during their long-distance migration.
Swainson’s Hawks may travel 12,000 miles round trip from the pampas of Argentina to Canada. They are birds of the open prairies and plains. Broad-winged Hawks have an average journey of 4,000 miles one way from northern South America to the northern U.S. and Canada, where they nest in forested areas.
Welcome Chimney Swifts
Chimney Swifts are due back in Austin as warm April weather generates more flying insects. These cigar-shaped aerial insectivores are looking for a home to raise their young, so if you have a clay flue tile chimney or a brick chimney, consider opening it up for the nesting season which runs from now until August. Keep it open until October when they leave, so they have a place to roost at night. You will be rewarded with the merry sounds of chittering birds throughout the summer. Please note that if your chimney is metal as many newer ones are, then keep it capped.
Did you know that there is a home in Austin that was built with Chimney Swifts in mind? Visit the Travis Audubon website and learn more about Chaetura Canyon and plan a visit this summer. It’s a magical place that is uniquely Austin.
Warblers on the Wing
An April bird forecast without a shout-out to warblers would be remiss. An uncommon one that is moving through Austin under the radar because of its secretive habits is the spectacular Hooded Warbler. The male’s black hood outlining a bright yellow face is helpful in identifying the bird. It also has bright yellow underparts and a yellow-green back. The female has a black or olive crown and sides of the neck. When they flick their tails, the white in the outer tail feathers is distinctive. On their breeding grounds in the eastern U.S. the Hooded Warbler favors dense understory, and good places to look in Austin are the Bouldin Creek greenbelt and along creeks where they will usually be low in the vegetation.
There are several Travis Audubon activities you will want to join this month. The main focus is fundraising Birdathon field trips which help support Travis Audubon’s conservation and education efforts.
Travis Audubon Monthly Meeting Join us for the April 30 meeting featuring Dr. Bruce Beehler of the Smithsonian Institution speaking on New Guinea’s lost worlds and the elusive Birds of Paradise. New location: First Unitarian Universalist Church Sanctuary, 4700 Grover Ave, Austin, TX 78756. Doors open at 6:30 with the speaker at 7:00 p.m.
Hornsby Bend Monthly Bird Walk April 20, 7:30 a.m. – 11:00 a.m. 2210 FM 973, Austin, TX. Hornsby is located just a little northeast of the airport off Hwy 71. Join us to explore Austin’s premier birding site. All levels of birders are welcome and no registration is required. Meet in front of the Center for Environmental Research. Wear closed toe shoes or boots and dress for the weather.
Birdability: Govalle Metropolitan Park April 20, 8:00 a.m. – 10:00 a.m.
Join Virginia Rose for a bird walk tailor-made for folks with mobility challenges.
Compiled by Jane Tillman, Travis Audubon Volunteer