The Lower Rio Grande Valley sits at a biogeographic seam. The Tamaulipan thornscrub of northeastern Mexico pushes up against the southern edge of the United States here, and a dozen tropical species reach the northern limit of their range in this 80-mile stretch of South Texas. Most of these birds occur regularly nowhere else north of the border.
If you're working on a U.S. life list, the RGV is mandatory. Here are ten of the most-wanted specialties and where to find each one.
1. Plain Chachalaca
A chicken-sized member of the family Cracidae, more closely related to a tropical guan than anything else in the U.S. Listen for the loud, rolling group chorus at dawn — once you've heard it, you'll never mistake it for anything else. Easiest at Bentsen-Rio Grande State Park and Santa Ana NWR, where they're habituated to feeders.
2. Green Jay
The cover bird of every RGV brochure for good reason — electric blue and yellow against a tropical green back. Bold, vocal, and easy to find at any of the major feeder stations. Bentsen, Estero Llano Grande, and the Edinburg Wetlands all reliable.
3. Altamira Oriole
Largest oriole in the U.S., a deep flame-orange with a black mask and back. Look for the basketball-sized hanging woven nests in mesquite or anacua. Resident at Bentsen, Santa Ana, and many private ranches. Often shares feeders with Audubon's Oriole.
4. Great Kiskadee
You'll hear the kiskadee before you see it — a loud, three-note shout that sounds like the bird is saying its own name. Bright yellow belly, brown back, black-and-white striped head. Common throughout the RGV in brushy country and along the river.
5. Hook-billed Kite
The hardest of the ten. A medium-sized raptor with a heavy hooked bill specialized for eating tree snails. Resident in tiny numbers along the Rio Grande corridor; most reliable from a boat between Anzalduas and Salineño. Bentsen and Santa Ana have occasional fly-overs.
6. Gray Hawk
A small, neat raptor with finely barred gray underparts and a banded tail. Tropical species that has been expanding north; now resident in the RGV and into parts of Arizona. Best looked for soaring over riparian woodland mid-morning. Common over the river itself.
7. Ringed Kingfisher
The largest kingfisher in the Americas, with a rattling call deeper and slower than a Belted's. Resident along the entire Rio Grande corridor. Easiest from a boat, but reliable from observation decks at Anzalduas and Santa Ana.
8. Green Kingfisher
Small, dark green, and shy — perches inches above the water on overhanging branches. The toughest of the three U.S. kingfishers. From the river, regular; from land, hit-or-miss. Listen for the dry ticking call.
9. Buff-bellied Hummingbird
A medium-sized hummingbird with a bright red bill and iridescent green throat that doesn't quite reach the buff belly. Resident in the RGV, common at feeders at Quinta Mazatlán, Bentsen, and the Edinburg Wetlands. Most regular at coral bean and Turk's cap blooms.
10. Olive Sparrow
A sneaky, ground-dwelling sparrow of thornscrub understory. More often heard than seen — a rapid trill that accelerates and runs down. Quinta Mazatlán and Sabal Palm Sanctuary are reliable for daylight looks. Patience required.
Honorable Mentions
If you have a full week, also chase Long-billed Thrasher, White-tipped Dove, Audubon's Oriole, Tropical Parula, Couch's Kingbird, Northern Beardless-Tyrannulet, and (if you're lucky) Red-crowned Parrot in McAllen at sunset. Each one is a possible U.S. lifer.
How to Build a Trip
A productive RGV birding week alternates trail days and river days. Trail days knock out the feeder species and the brush specialties. River days knock out the kingfishers, the kite, the hawk, and the species that live on the water.
I run morning and sunset river trips from Chimney Park RV Resort, four guests maximum. If you're already booked into the RGV for a few days, adding a river morning is the highest-value half-day on your itinerary.