South Texas cuckoo birds are on the move in the Rio Grande Valley
Published September 19, 2026, in the McAllen Monitor
Story and photos by Anita Westervelt
Be on the lookout for gregarious groups of groove-billed ani, unique, highly social Rio Grande Valley summer birds in the cuckoo family. The birds have glossy, coal black plumage, short, broad wings, a very long, floppy tail, and big, curved bill with distinct grooves.
If you’re out in nature the next few weeks and hear a low fracas of gentle clattering and squabbling, stay still and look around. It might be a small gaggle of groove-billed ani. Scan the low shrubby bushes; the birds are active and noisy ground foragers.
My first experience with these fun and charming birds was discovering three or four of them had been watching me weed a flower bed from their perch a couple of feet above my head where they sat quietly in a spindly tree. They quickly flapped off upon my noticing them.
If you’re near an old honey mesquite, check the low tangled branches. Groove-billed ani like to hop around checking for prey. They also like to perch together and pose for photographs.
One late summer afternoon a low-key ruckus got my attention. I slowly looked around. A half dozen groove-billed anis seemed to be playing ring-around-the-Rosie at the edge of a colony of Turk’s cap at the base of an old mesquite tree. Above, several others were posing on branches. Further afield, an ani was snapping at insects, bouncing up and down in the frog fruit like a jack-in-the-box, while another watched from a nearby young black willow tree.
During their summer breeding season, groove-billed anis are highly territorial. They return to the same brushy habitats each day, relying on their carefully selected area to provide enough to feed themselves and their chicks.
Groove-billed anis are communal nesters with one to five monogamous breeding pairs. In spring, when they arrive in the Rio Grande Valley, site selection encompasses five to 10 acres and has to meet stringent criteria:
Thick thorn forests with old growth Texas ebony, mesquite and acacia trees are the first consideration, or a citrus orchard. The trees provide thick cover for their large communal nest. The ideal site will feature a distinct edge-habitat right next to the thorn scrub and border open grasslands, pastures, or agricultural fields, which allows the birds to forage in the open and quickly retreat into protective brush when threatened.
The habitat will have high populations of grasshoppers, crickets, beetles, caterpillars, cockroaches, lizards and spiders.
A fascinating micro-criterion for site selection, according to “Birds of the World,” is anis deliberately choose a tree with active wasp nests in it. The protective, aggressive nature of the wasps provides passive security from climbing predators, like snakes and small mammals.
Their breeding season ends around September, and they begin moving around the Rio Grande Valley in their small established groups; you may come across them when you least expect it. This late-summer and autumn roaming is a staging phase where they freely canvas the Valley's habitats and fatten up on seeds, berries, and insects before their October flight to Mexico.
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A few groove-billed ani hotspots in the Rio Grande Valley
Compiled by Anita Westervelt
Dense native brush areas and local nature parks are hotspots across the Rio Grande Valley for possible sightings of groove-billed ani through October.
Estero Llano Grande State Park, Weslaco. Keep an eye out around the margins of the park’s shallow lakes and wet brushy pastures.
Frontera Audubon, Weslaco. Check the thick bushes on the right along the driveway and then further in where the dense forest breaks into open grassy space.
Santa Ana National Wildlife Refuge, Alamo. Ask the volunteers at the visitor center to check the recent sightings log.
Bentsen-Rio Grande Valley State Park, Mission. The dense, messy undergrowth surrounding the park's feeding stations and tram roads provides the low-shrub coverage they love.
Resaca de la Palma, Brownsville. Search the dense canopy and edges of the ebony forest, where they are known to quietly watch visitors. Consider a guided tram tour.
Palo Alto Battlefield National Historical Park, Los Fresnos. Begin searching at the brushy borders surrounding the main parking lot and trailhead then along the short nature trail that crosses the coastal brush and prairie near there.
South Padre Island Birding & Nature Center and adjacent Convention Center. Search the thick vegetation, ornamental trees, and island brush wraps immediately surrounding the SPI Convention Center parking lot and boardwalks.
Sabal Palm Sanctuary, near Brownsville. The entrance bushes and forest edges are classic spots to look for groove-billed ani.
Laguna Atascosa National Wildlife Refuge, Los Fresnos. Focus on the low, dense Tamaulipan thorn scrub and edges of the open brushy fields.
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