Rio Grande Valley Raptors

Tiffany KerstenBirding2 Comments

As fellow Nemesis Birder Alex Lamoreaux was out looking for one of his nemesis birds today, I was sitting in my office a few miles away, pining to also be on the Mission Nature Park levee, scanning the skies for the local group of Hook-billed Kites which have been rather faithfully putting on a show for any interested birders who came to watch for the past several months. Amidst my daydreaming, I got to thinking, some of our Rio Grande Valley hawks are pretty dang cool. Here’s my pick of the funkiest predators around:

Hook-billed Kite: Land snails are this hawk’s exclusive food source. There has been a group of five of them seen occasionally at Mission Nature Park lately. They are incredibly unique as they spend most of their time climbing around in trees to find the snails, but are sometimes seen flying to their feeding site in the morning and flying back to their roost site in the early evening. Their bill is specially designed to extract snails from their shells. In Mexico, where there are two different types of land snails, there are two separate variations of this species of bird. One with a smaller bill feeds on the smaller snails, and one with a bigger bill feeds on the bigger snails!

Hook-billed Kite, Mission Nature Park, Texas (photo by Tiffany Kersten)

Hook-billed Kite, Mission Nature Park, Texas (photo by Tiffany Kersten)

Another interesting trait of these snail-eating raptors is that there exists a black morph which is very uncommon and is only seen, at best, a few times a year in Texas. A black morph female nested at Bentsen-Rio Grande Valley State Park in the early 2000s, and raised one black morph chick. Sporadic sightings – usually a few a year – occurred over the past 15 years, until this year, when the black morph was seen almost daily with a group of typical birds for several months. Sorry—this was the best look I have gotten at the black morph, and it is therefore also the best look that you get of it. Unlike the typical morph, the black morph has only a single white tail band, rather than several light and dark bands.

Black morph Hook-billed Kite, Mission Nature Park, Texas (photo by Tiffany Kersten)

Black morph Hook-billed Kite, Mission Nature Park, Texas (photo by Tiffany Kersten)


Harris’s Hawk: While out birding, you might notice that often when you see one Harris’s hawk, there are usually more. These hawks hunt cooperatively, often in groups of three to five. Some will perch high and be on the lookout, and others will be part of the hunt squad. I’ve witnessed (and listened to) the successful kill of an eastern cottontail rabbit at Santa Ana National Wildlife Refuge. Several hawks were perched up; I watched one fly away from me, down towards a lake, heard a brief squeaking sound, and then silence. After a successful kill, these hawks will share their meal with the others in their pack.

Though I have yet to personally witness it, Harris’s hawks will occasionally exhibit the unusual behavior of stacking, or literally piling on top of one another, in order to gain altitude and locate prey. Since these are birds of flat scrubland, that extra foot or two of elevation can mean the difference between a successful meal or a hungry evening. They’ll sometimes stack themselves three high. Better work on those tarsus muscles!

Zone-tailed Hawk: These hawks look very much like vultures. They fly with a dihedral just like turkey vultures, but the adults can be distinguished from vultures by the black “3” under their tail, and both juveniles and adults have fine barring on the feathers, and yellow cere. They are a bit differently shaped and weigh more than vultures, so they don’t get pushed around in the wind quite as much, but until you become familiar with them, check every vulture with scrutiny! You will often see them soaring or circling near the bottom of a kettle of vultures, searching for prey. While vultures eat mostly road kill, the zone-tailed hawks take advantage of their ability to blend in with the vultures in order to surprise prey, mainly small birds and lizards. Most creatures have learned that vultures are not interested in them, and therefore they will not hide as readily when they think there are only vultures overhead.

The Rio Grande Valley has been hopping with raptors as of late—spring migration has begun! Come on down for a visit!

What is your favorite raptor, and why? Which raptor is YOUR nemesis bird?