Where to See Colima Warblers in Big Bend National Park, and When They're Here

An adult Colima warbler in fresh spring oak leaves. Observed in Brewster County, TX, USA, on April 17, 2024. Photo: Tom Field, CC BY 4.0, via iNaturalist; cropped, with lettering added by Brian Russ Guides.

If you want to see a Colima warbler in the United States, there's one place to go: the high oak woodlands of the Chisos Mountains in Big Bend National Park. The park says plainly that Big Bend is the only place in the country to see it (NPS). That's why birders hike to Boot Canyon on spring mornings.

It isn't flashy or easy: you'll hike several miles uphill, come in the right months, and find it mostly by ear. For the rest of the visit, my guide to Big Bend National Park lays out one- to three-day plans by effort level.

Why the Colima warbler is special in Big Bend

The Colima warbler (Leiothlypis crissalis) is a Mexican mountain bird. It breeds high in the Sierra Madre Oriental and spends the nonbreeding season on Mexico's Pacific slope; its range barely reaches the U.S. in the Big Bend region (All About Birds).

A male collected in Boot Canyon in 1928 pushed the known range north into Texas, and the park notes that ornithologists have searched other southwestern sky islands without finding it. That's the useful comparison: Chiricahua's oak-pine canyons in Arizona look like they could hold one, but if this bird is on your list, Big Bend is the trip.

The Texas population is small. Audubon puts it at probably fewer than 200 pairs, with numbers that rise and fall from year to year (Audubon).

How to recognize a Colima warbler

It's a gray-brown warbler about 5 to 6 inches long, a bit larger than most warblers (Audubon). The marks to look for are a neat white eye-ring and bright yellow under the base of the tail, which both sexes show (All About Birds). There's also yellow on the rump and a rust-colored crown patch (NPS).

The song is a musical, repeated "seedle" phrase, and the call is a sharp "plisk" (Audubon). Learn it before you go; you'll usually hear the bird first.

The look-alike is Virginia's warbler, which passes through Big Bend in migration. Virginia's is smaller and lacks the brown wash on the sides (Audubon); Colima also has a heavier bill and grayer breast (Wikipedia).

An adult Colima warbler among new oak leaves, showing the white eye-ring and yellow undertail. Observed in Big Bend National Park, TX 79834, USA, on April 28, 2003. Photo: Dan Vickers, CC BY 4.0, via iNaturalist.

Where and when to look in Big Bend

Timing comes first. Colima warblers usually arrive in late April and are gone by August (NPS); Audubon says most leave in August and early September. If you're reading this in late fall or winter, they're in Mexico. Plan on late April through July. If a winter trip is what's on your calendar, my notes on Big Bend in winter cover that season well; just don't count on this bird.

Place comes second. In Texas the birds breed above about 6,000 feet, in pine, juniper, oak, and madrone woodland, or oak, maple, and Arizona cypress (Audubon). The park points to the oak woodlands of Boot Canyon as the classic spot, says territories run from Green Gulch to Boot Canyon, and adds that you may get lucky along the Lost Mine Trail or around the Chisos Basin Campground (NPS).

How to plan a Boot Canyon day

Boot Canyon is 3.5 miles one way from the Chisos Basin Trailhead, and the South Rim is another 2.5 miles past it; the full South Rim loop runs 12 to 14.5 miles with about 2,000 feet of climbing (NPS). The park describes the Boot Canyon and Laguna Meadows route as about 4.5 miles of steep, rugged terrain, and says to carry plenty of water and plan a full day (NPS).

My take: on a two- or three-day trip, give the warbler your mountain day. Start from the Basin at first light, both to beat the heat and because you're hunting by ear, and walk slowly once you reach the oaks. The park's best tip is to wait quietly near water, since the birds come down to drink and bathe. If you can't manage the full hike, the Lost Mine Trail (4.8 miles round trip, from mile 5.1 on Basin Road, with limited parking) is a shorter gamble, not a sure thing.

Two practical notes. The northeast and southeast sections of the South Rim close during peregrine falcon nesting season, so check before planning the full loop (NPS). And Chisos Basin Campground is open year-round but reservation only, which matters if you want to be on the trail at dawn.

A Colima warbler on the ground with something green in its bill, showing its yellow rump. Observed in Brewster County, TX, USA, on June 20, 2010. Photo: nmoorhatch, CC BY 4.0, via iNaturalist.

What it does all summer

Colima warblers eat insects and spiders, gleaning them from foliage (All About Birds). Audubon calls them sluggish foragers that work dense undergrowth and lower oak branches, which helps: this isn't a warbler that vanishes into the treetops.

They feed in trees but nest on the ground, tucked under rocks, grass, or dry leaves (NPS). That's one more reason to stay on the trail in Boot Canyon. By late summer they head south to winter in southwestern Mexico (Audubon).

A Colima warbler foraging head-down in a pine, seen from below. Observed in Brewster County, TX, USA, on May 13, 2024. Photo: William Harmon, CC BY 4.0, via iNaturalist.

Watching responsibly

This is a small population, so be gentle. Don't play recorded songs or calls; the park warns that playback can drive birds off their nests. Use binoculars instead of moving closer, stay on the trail, and never go looking for a nest. Don't feed or bait birds. And if you post your sighting, keep the location general, the way the park does.

Fitting the warbler into a Big Bend trip

The warbler pairs well with the rest of the Chisos. While you're in the Basin, you may meet the Mexican jays I wrote about in Big Bend's roadrunners, black bears, and fall tarantulas, and the hike into warbler country is the same one that gets you to the South Rim's views.

My Big Bend National Park guide has nine one- to three-day itineraries at easy, moderate, and strenuous effort, including the South Rim, plus a wildlife chapter on the animals visitors commonly see.

Before you go: see Big Bend National Park alerts and current conditions, checked daily, for current closures and what they mean for your trip.

This is an independent guide. It is not affiliated with or endorsed by the National Park Service. Conditions change; check the park's current alerts before you go.