From savannas, to subtropical forests, to desert scrub there is no better springtime paradise for hawkwatchers than southern Texas. Huge numbers of migrant raptors slip northward along the coastline, taking the shortest possible route around the Gulf of Mexico, and 11 different species call the southern portion of the state their year-round home. There are even a few species that can be found nowhere else in the country including White-tailed Hawk, Hook-billed Kite, and the notorious Aplomado Falcon! The entire Lower Rio Grande Valley can be fantastic for watching birds of prey, from family groups of Harris’s Hawks hunting through the mesquite woodlands to spectacular mixed-species kettles migrating north, this region is really like no other. Below I breakdown the raptors that can be found throughout the Valley during April, their typical habits and habitats, and some general thoughts and anecdotes from my recent Nemesis Bird Nature Tour of south Texas. A visit to south Texas should be on every raptor-lovers bucket list.
Raptors of South Texas….
Black and Turkey Vultures
Both vultures are common throughout southern Texas, with Black Vultures tending to be more local residents that stick closer to human habitats, and Turkey Vultures often seen migrating north in large numbers and following kettles of Broad-winged Hawks and Mississippi Kites. For how common and ubiquitous the vultures are, there is something completely captivating to me about seeing long lines of Turkey Vultures advancing northward. During 10 days of birding, I saw 275 Black and 1000 Turkey. Undesirable locations to go birding, like the Brownsville Dump, are excellent for seeing large numbers of both vultures. Turkey Vultures were an even mix of adults and immatures, easily separated by the state of their wing molt – immatures (first year birds) were molting in new inner primaries, giving them a unique profile when soaring.
These fish-eating raptors are obviously tied to the waterways and coastal lagoons of South Texas, and are uncommon residents and common migrants through the region. During 10 days of birding, I saw 50 Osprey – mostly within 5 miles of the coastline, and observed a few pairs but didn’t see any breeding evidence.
These handsome kites are uncommon residents in the region. During 10 days of birding, I saw 15 White-tailed Kites. All of my sightings were of adults, and many were paired or clearly on territories, as they were often seen mobbing large soaring raptors. Look for the kites hovering over open areas such as savannas, grasslands, and around the brushy edges of agricultural areas. The breeding density of White-tailed Kites in south Texas is rivaled only by central California.
‘Hookers’ are rare in the Valley, but there’s no better chance to see one in the United States than along the Rio Grande. This species is rare in northern Mexico too, but the current thinking is that some fly north into the extensive nature preserves along the US side of the border during the early morning, feed on snails throughout the day, and then sneak back south into Mexico to roost each night. There have been recent instances, though, where one or two Hook-bills have overwintered at Bentsen State Park and other locations throughout the upper portion of the Valley. During 10 days of birding, I didn’t see any Hook-billed Kites despite considerable effort. During my time in the region there were 3 reports, all from Bentsen State Park (and all not photographed). I’d warn visiting birders that Harris’s Hawks are fairly similar in shape and size to Hook-bills; with paddle-like wings, long and thick tails, etc. I saw more than one person mis-ID a high-flying Harris’s for a Hook-billed, and I’ll admit that one soaring insanely high over Sabal Palm Sanctuary had me going for a few minutes. I have seen an adult female Hook-billed Kite on a previous spring visit though – in early March at the Salineno boat launch. Your best bet for seeing one in the Valley is to spend morning at an overlook, and watch as raptors soar up out of the trees and move north.
Another stunning and graceful kite that is an uncommon migrant through the Valley. During my 10 days of birding, I only saw 3 Swallow-tailed Kites but they are more numerous during late March so I was a bit past their peak window. The best chances of seeing one are to be diligent about scanning the scattered, soaring raptors you spot while driving around and birding, or to watch the morning raptor lift-offs from the overlooks provided at refuges such as Santa Ana NWR and Bentsen State Park.
Along with Broad-winged Hawks, almost the entire population of Mississippi Kites migrant through southern Texas twice per year! April is the peak time to see them coming through, and I saw 2300 during 10 days. These kites travel northward in huge, spiraling kettles and their movements are closely tied to the weather. Small numbers can be seen lifting off and migrating north almost any day, but large groups depend on how storms and wind direction clump them together and back them up, and limits when their mass exoduses occur. Large numbers will also drop into large trees and roost communally during the evenings.
Harriers are rare by mid-spring in the Valley, and I didn’t see any during 10 days there. There were scattered reports by other birders in agricultural areas however, so I must have just had bad luck. Just a bit north of where I’m covering with this article (east of Houston at Anahuac NWR), I saw 10 ‘brown type’ harriers in one day, clearly preferring the wet coastal marshes over the dry river plain.
These tiny raptors are common migrants through the valley, and are most often seen when soaring high overhead alone or with smaller numbers of other migrants. During 10 days, I saw 7 Sharpies and they were a mix of ages. Who knows how many others snuck past over my head though!
This species is becoming a common breeder in this region, taking advantage or both human and natural environments, and is presumably a rare migrant. During 10 days, I saw 6 Cooper’s Hawks. All of my sightings were of adults performing their over-animated display flights, or just flying past at low altitudes. Watching for them to soar up during the mornings is your best bet for seeing them because once they get down into the trees for the day, they can be fairly secretive.
Harris’s Hawks are abundant in southern Texas. Family groups ranging from 2 to 7 or more Harris’s can be seen hunting together through the savanna, ranchlands, and subtropical woodlands of the Valley. Individuals within a group take on different roles; with some perching up high and watching over an area, while others scout ahead for prey, and others follow up with actually doing the killing of rodents and cottontails. Immatures may also be uncommon migrants into the region, as I had multiple observations of them soaring very high up and loosely associated with other migrant raptors moving north. Perhaps these are just bored local birds out for a casual soar or maybe they dispersing from where they were fledged…? During 10 days I saw 80 Harris’s Hawks.
These unique Buteos are arguably the coolest raptors in south Texas. They are similar to Red-tailed Hawks in size and general shape when perched, but in flight have distinctly short tails and very broad wings that quickly taper to rather pointed primaries. During 10 days I saw 22 White-tailed Hawks, and 80-90% were adults. Immatures have variable plumage, from lightly-marked to heavily-marked. White-tailed Hawks prefer to perch on the tops of yucca (locally called Spanish Daggers), and kite low over grasslands. They rarely stray into forested areas, and are much more common across savanna and ranchlands than near forests. This quintessential raptor’s population is thankfully stable and/or increasing throughout southern Texas.
These subtropical raptors are uncommon residents throughout the more natural and expansive habitats of the Lower Rio Grande Valley. During April it is common to see adult pairs patrolling their territories and immatures roaming around. In 10 days of birding I saw 8 Gray Hawks; and areas where you can get close to the Rio Grande or other waterways are great for them, since they nest in riparian trees. They are experts at catching whiptail lizards, and often hunt very Accipiter-like from inside the forest canopy. Beware of immatures which might slip past as ‘just another immature Broad-wing’ – they are similar in shape and patterning, but usually more sharply dark brown-and-white on their undersides and don’t have the pinched primary shape of a soaring Broad-wing. Immatures also have clean white cheeks, unlike any other Buteo.
Although common throughout the southern United States, Red-shoulders are fairly rare in the Lower Rio Grande Valley. During 10 days, I only saw 3 – two adults chasing each other near McAllen, and one adult soaring over Sabal Palm Sanctuary. Any sightings of adults, especially presumed pairs should be reported to eBird.
Like I mentioned above, virtually all of the Broad-winged Hawks in the United States migrate back and forth through the Valley during migration, so it should be no surprise that they are commonly seen and are often in large groups. During 10 days, I saw 150 Broad-wings which is a bit lower than I anticipated but I had just missed their peak movement during April 9th and 12th when over 12,000 were recorded at Bentsen State Park’s hawkwatch. Fall is without a doubt the better time to see huge numbers of Broad-wings moving through southern Texas, and daily counts of 20,000+ happen every year. A mixture of ages is expected during April, and I noted a few particularly beautiful (and uncommon) heavily-marked type adults during a few morning hawkwatching efforts. Comparing Broad-wings side-by-side to various other Buteos is always a treat!
These lanky Buteos are common migrants and uncommon residents in south Texas. Small numbers are often mixed with kettles of Broad-winged Hawks and Mississippi Kites, and small groups can sometimes be found foraging for insects as loose groups in agricultural areas. During 10 days I saw 120 Swainson’s, and 95% were light color-types, and most were immatures. Almost any time of day you can scan the skies and pick out at least one Swainson’s lazily soaring around, and occasionally you’ll catch small groups gathering to roost communally in clusters of tall trees in the late evenings.
Red-tailed Hawks are uncommon in much of south Texas, and most are thought to represent the very lightly-marked Fuerte’s subspecies, although intergrades are probably rampant where their range meets Eastern birds. During 10 days I saw 7 Red-tails, and all were adults (some in pairs) and all had minimal markings on their undersides and underwing coverts as would be expected from Fuerte’s. Lingering Eastern birds that overwintered in the region should be expected as well.
These vulture-mimics are rare visitors and migrants to south Texas, and during 10 days I didn’t see any, although there were one or two sightings in the region by other birders during my visit. The Upper Valley is the best area to find them, and they are often mixed with soaring Turkey Vultures. Zone-tailed Hawks are more common further west in Texas’ rolling hills and scrubby deserts.
Unmistakable and quite common in south Texas, Crested Caracaras are always a crowd-pleaser with visiting birders. Caracaras are common residents, and can be found as singles or pairs throughout the Valley. During 10 days I saw 95 Crested Caracaras, with a fairly even mix of adults and immatures represented. Perhaps the best place to see them in good numbers and at close range is the Brownsville Dump, but they are easily encountered throughout brushy savanna and ranchlands of the entire region.
By April most kestrels have already migrated through south Texas, but during 10 days I saw 15 and most were females. Interestingly, during both of my morning visits to Salineno and Chepano I saw female kestrels flying due north around 8-9am while they were mostly very rare or not actively migrating elsewhere in the Valley.
This infamous falcon is rare by April in the region, but can still be found where avian prey congregates. During 10 days I had 2 observations of Merlin – one adult female Prairie subspecies watching over foraging shorebirds at a large sod farm, and a probable Taiga subspecies flying through the famous parrot roost at Oliviera Park. Careful observation and documentation of Merlins in southern Texas during winter would be beneficial in determining the breakdown of subspecies using this region.
Adult and immature Peregrines are uncommon throughout the Lower Rio Grande Valley during April, but migrants and lingering winter-residents can be found without much effort. During 10 days, I saw 7 Peregrines representing a mix of ages. Water towers and other prominent perches are classic places to scan for them, but they can also be spotted cruising high overhead on days with good weather conditions for raptor migration. Multiple subspecies from across the country could presumably be documented here.
The holy grail of Texas raptors. Aside from very rare sightings in southeastern New Mexico, the colorful Aplomado Falcon can’t be found anywhere else in the country other than the coastal grasslands and savanna of south Texas. During 10 days I saw 5 individual adults; two adult pairs and a solitary adult. All of my sightings were along Old Port Isabel Rd and Highway 100 near Laguna Vista, but they can also be found in certain portions of Laguna Atascosa NWR. During April, Aplomados are nesting and their territories are purposely distant from roads – often offering only scope views. Patience may be rewarded though….after 12 hours of waiting and watching over the course of 2 days, I was able to get the shot below when one of the Old Port Isabel falcons flew right past my car! No doubt off to terrorize some meadowlarks and other small songbirds! If you’re wondering about their unusual name, “aplomado” means lead-colored, which describes the bird’s uppersides.
Habitat destruction and alteration has significantly reduced their population within the United States, but reintroduction efforts and Great Horned Owl-proof nesting structures have helped to maintain a stable population in the Lower Rio Grande Valley. This incredible falcon should be the poster species for habitat conservation in the region, and I sincerely hope every visiting birder gets the opportunity to enjoy them now and well into the future.
Rare Raptors of South Texas…
Nowhere else in the country is there such a high probability of spotting a truely rare-to-the-US raptor as along the Rio Grande. And although the following species are very rare in the Lower Rio Grande Valley, these Central American species deserve mention as they have been or could be encountered during spring…especially if more birders are prepared to spot them!
There are at least 8 records of this species during fall, winter, and spring for south Texas and they have been found randomly along the entire length of the Lower Rio Grande Valley. Expansive areas of protected subtropical woodlands are the most likely places to encounter one, and they are thought to probably be annual visitors from eastern Mexico – though very rarely documented. Most records are of immatures birds, but all ages are fairly unique in plumage patterns and overall structure…something like a smaller Red-shouldered Hawk, but with more dark barring and streaking. As their name suggests, they will often perched conspicuously along roadside and at the edge of forest patches.
There is currently only one record of this species in the United States, from the winter of 1987/1988. Crane Hawks are unlike any other raptor in this region; mostly black in color, overall lanky like a Cooper’s Hawk, but uniquely broad-winged, and with a small, dove-like head. Their resident habits in Mexico combined with the disheveled look of the single Texas record has caused many to think it may have been a released bird brought up from Central America. Maybe you’ll be the one to spot the country’s 2nd record, and we can start to develop a better theory on their movements – whether natural or assisted by humans!
Collared Forest Falcon
This is another Central American species that is totally unlike any other raptor native to south Texas, and another species that has only been recorded once in the region – during the winter of 1994. As their name suggests, Collared Forest Falcons are secretive forest-adapted species and are most often detected by their loud calls.
So far not documented in the Lower Rio Grande Valley, but there was a photographed record of an immature from High Island (the Gulf Coast’s top songbird migrant trap) in the spring of 2011. These small raptors resemble Sharp-shinned Hawks in shape and flight style, and were previously not thought to be migrants, however that idea is quickly changing – or at least the idea of northward expansion is starting to catch on – as the northward incursion of Crested Caracaras and Common Black Hawks can attest to. Double-toothed Kites are definitely something to keep in the back of your mind when hawkwatching in the Valley!
Hawk-watching Sites in South Texas…
Almost anywhere in the Lower Rio Grande Valley can be excellent for raptor-watching, but there are a number of locations and areas that are particularly fantastic and some even have dedicated, seasonal hawk counts. A few of the more famous sites for viewing spring raptor migration include the Hawk Tower at Bentsen State Park, the Tree Tower and dike at Santa Ana NWR, the Salineno boat launch, Mission Nature Park, Old Port Isabel Rd, Anzalduas Park, and South Padre Island. The best areas for driving around and seeing a variety of resident raptor species include Highways 281, 77, and 83 as well as the eastern portion of Boca Chica Blvd and Laguna Atascosa NWR. Interior portions of the Valley with roads through ranchlands, particularly Highway 285 (aka Hawk Alley) in Kleburg County, can be very productive for roadside raptors.
Raptor Research in South Texas…
Aside from the raptor migration counts at Bentsen State Park and Santa Ana NWR, there are a few other projects related to birds of prey currently happening in south Texas. World-renowned raptor expert, Bill Clark, lives in the region and has been banding raptors here for decades…if you look at Harris’s Hawks closely, you may see some that were banded by Clark and his colleagues! Along with Joaquin Galindo, Bill Clark has also started a new project to document ‘rare’ breeding raptors in Cameron and Hidalgo Counties that birders can help contribute to. If you have visited the area since April 1st, or plan to visit before the end of August and observe any breeding evidence of Cooper’s Hawks, Gray Hawks, Red-shouldered Hawks, and Swainson’s Hawk in those two counties please report your sightings to eBird as well as Joaquin (firstname.lastname@example.org) or Bill (email@example.com). They are also interested in breeding-related sightings and observations of Osprey, White-tailed Kites, Hook-billed Kites, both vultures, Crested Caracara, and White-tailed Hawk. Please include a description of the species, nest tree species (if a nest is found), date, exact location, and any other pertinent information. As the habitats of the Lower Rio Grande Valley continue to change and evolve, it is critical to keep careful records of nesting raptor observations and monitor each species’ distribution and abundance throughout the region.