Those mid-summer post-breeding wanders continue to delight birders throughout the Mid-Atlantic States. One colorful denizen of ponds and wetlands that has yet to put in an appearance in the Lower Susquehanna River Watershed this year is the Black-bellied Whistling Duck. You might remember this species from earlier posts describing the fortieth anniversary of your editor’s journey to the Lower Rio Grande Valley of Texas. Like many other birds, the Black-bellied Whistling Duck has been extending its range north from Texas, Florida, and other states along the Gulf Coastal Plain. Populations of these waterfowl are chiefly resident birds with some short-distance movement to find suitable habitat for feeding and nesting. They are not usually migratory, so summertime wandering may be the mechanism for their discovery of new habitats advantageous for nesting in areas north of their current home.
Presently, at least two dozen Black-bellied Whistling Ducks are being seen regularly at a stormwater retention pond in a housing subdivision along Amalfi Drive west of Smyrna, Delaware. This small population of avian tourists has spent at least two summers in the area. Just yesterday, Black-bellied Whistling Ducks were seen and photographed about ten miles to the east at Bombay Hook National Wildlife Refuge. Nine were counted there while 27 were being watched simultaneously at the Amalfi site. Earlier this week, a single Black-bellied Whistling Duck visited the John Heinz National Wildlife Refuge in Philadelphia, indicating that the influx of these vagrants has transited the entire Delmarva Peninsula and entered Pennsylvania. So while you’re out watching for those first southbound migrants of the year, be on the lookout for wayward wanderers too—wanderers like Black-bellied Whistling Ducks!
Back in late May of 1983, four members of the Lancaster County Bird Club—Russ Markert, Harold Morrrin, Steve Santner, and your editor—embarked on an energetic trip to find, observe, and photograph birds in the Lower Rio Grande Valley of Texas. What follows is a daily account of that two-week-long expedition. Notes logged by Markert some four decades ago are quoted in italics. The images are scans of 35 mm color slide photographs taken along the way by your editor.
DAY FOUR—May 24, 1983
“AOK Campground—South of Kingsville, Texas”
“Arose at 6:30 A.M. to the tune of Common Nighthawks. After breakfast, we headed for Harlingen. While driving south we saw six pairs of Black-bellied Whistling Ducks. At Harlingen we phoned Father Tom, who is an expert birder for the area.”
As we drove south to Harlingen, much our 100-mile route was through the Laureles division of the King Ranch, the largest ranch in the United States. It covers over 800,000 acres and is larger than the state of Rhode Island. The road there was as straight as an arrow with wire fences on both sides and scrubland as far as the eye could see. Things really are bigger in Texas.
Once in Harlingen, we did two things no one needs to do anymore:
Find a coin-operated telephone to place a call to Father Tom.
Ask Father Tom for the latest tips on the locations of rare and/or target birds.
Today, nearly everyone traveling such distances to find birds is carrying a cellular phone and many can use theirs to access internet sites and databases such as eBird to get current sighting information. Back in 1983, Father Tom Pincelli was a dear friend to birders visiting the Lower Rio Grande Valley. Few places had a person who was willing to answer the phone and field inquiries regarding the latest whereabouts of this or that bird. To remain current, he also had to religiously (forgive me for the pun) collect sighting information from the observers with whom he had contact. For locations elsewhere across the country, a birder in 1983 was happy just to have a phone number for a hotline with a tape-recorded message listing the unusual sightings for its covered region. If you were lucky, the volunteer logging the sightings would be able to update the tape once a week. For those who dialed his number, Father Tom provided an exceptionally personal experience.
Since 1983, Father Tom Pincelli, also known as “Father Bird”, has tirelessly promoted birding and conservation throughout the Lower Rio Grande Valley. His efforts have included hosting a P.B.S. television program and writing columns for local newspapers. He has been instrumental in developing the annual Rio Grande Valley Birding Festival. The public sentiment he has generated for the birding paradise that is the Lower Rio Grande Valley has helped facilitate the acquisition and/or protection of many key parcels of land in the region.
“After receiving information on locations of Tropical Parula, Ferruginous Pygmy Owl, Hook-billed Kite, Brown Jay, and Clay-colored Robin, we went on to check out the Brownsville Airport where we will meet Harold and Steve Thursday noon.”
If we were going to see these five species in the American Birding Association listing area, then we would have to see them in the Lower Rio Grande Valley. All five were target birds for each of us, including Harold who had few other possibilities for new species on the trip. Father Tom provided us with tips for finding each.
I noticed as we began moving around Harlingen and Brownsville that Russ was swiftly getting his bearings—he had been here before and was starting to remember where things were. His ability to navigate his way around allowed us to keep moving and see a lot in a short time.
In Harlingen, we easily found Mourning Doves and the non-native Rock Pigeons, species we see regularly in Pennsylvania. We became more enthusiastic about doves and pigeons soon after when we saw the first of the several other species native to south Texas, the diminutive Inca Dove (Columbina inca), also known as the Mexican Dove.
“Next, to the Brownsville Dump to see the White-necked Ravens — Then to Mrs. Benn’s in Brownsville for the Buff-bellied Hummingbird. Both lifers for Larry.”
For birders wanting to see a White-necked Raven in the Lower Rio Grande Valley, the Brownsville Dump was the place to go. With very little effort—excluding a trip of nearly 2,000 miles to get there—we found them. Today, birders still go to the Brownsville Dump to find White-necked Ravens, though the dump is now called the Brownsville Landfill and the bird is known as the Chihuahuan Raven (Corvus cryptoleucus).
Mrs. Benn’s home was in a verdant residential neighborhood in Brownsville. She welcomed birders to come and see the Buff-bellied Hummingbirds that visited her feeder filled with sugar water. I don’t recall whether or not she kept a guest book for visitors to sign, but if she did, it would have included hundreds—maybe thousands—of names of people from all over North America who came to her garden to get a look at a Buff-bellied Hummingbird. After arriving, we waited a short time and sure enough, we watched a Buff-bellied Hummingbird (Amazilia yucatanensis) sipping Mrs. Benn’s home-brewed nectar from her glass feeder. This emerald hummingbird is primarily a Mexican species with a breeding range that extends north into the Lower Rio Grande Valley of Texas. When not breeding, a few will wander north and east along the Gulf Coastal Plain as far as Florida.
Other finds at Mrs Benn’s included White-winged Dove (Zenaida asiatica), Ash-throated Flycatcher (Myiarchus cinerascens), Brown-crested Flycatcher (Myiarchus tyrannulus), and Black-crested Titmouse (Baeolophus atricristatus), a species also known as Mexican Titmouse.
The Lower Rio Grande Valley from Rio Grande City east to the Gulf of Mexico is actually the river’s outflow delta. At least six historic channels have been delineated in Texas on the north side of the river’s present-day course. An equal number may exist south of the border in Mexico. Hundreds of oxbow lakes known as “resacas” mark the paths of the former channels through the delta. Many resacas are the centerpieces of parks, wildlife refuges, and housing developments. Still others are barely detectable after being buried in silt deposits left by the meandering river. Channelization, land disturbances related to agriculture, and a boom in urbanization throughout the valley have disconnected many of the most recently formed resacas from the river’s floodplain, preventing them from absorbing the impact of high-water events. These alterations to natural morphology can severely aggravate flooding and water pollution problems.
“On to Santa Ana National Wildlife Refuge. We walked to Pintail Lake and saw 6 Black-bellied Whistling Ducks and 2 Mississippi Kites and 1 Pied-billed Grebe. We drove the route thru the park with great results—Anhingas, Least Grebe, and more Black-bellied Whistling Ducks.
Santa Ana National Wildlife Refuge on the Rio Grande is not only a birder’s mecca, 300 species of butterflies have been identified there. That’s half the species known to occur in the United States! Its subtropical riparian forest and resaca lakes provide habitat for hundreds of migratory and resident bird species including many Central and South American species that reach the northern limit of their range in the Lower Rio Grande Valley. Two endangered cats occur in the park—the Ocelot (Leopardus pardalis) and the Jaguarundi (Herpailurus yagouaroundi).
We saw no cats at Santa Ana, but did quite well with the birds. Our list included the species listed above plus Cattle Egret (Bubulcus ibis); Louisiana Heron, now known as Tricolored Heron (Egretta tricolor); Plain Chachalacas; Purple Gallinule; Common Gallinule (Gallinula galeata); American Coot; Killdeer; Greater Yellowlegs; the coastal Laughing Gull (Leucophaeus atricilla); and its close relative of the central flyway and continental interior, the Franklin’s Gull (Leucophaeus pipixcan). Others finds were White-winged Dove, Mourning Dove, Inca Dove, Yellow-billed Cuckoo, Golden-fronted Woodpecker, Ladder-backed Woodpecker (Dryobates scalaris), Brown-crested Flycatcher, Altamira Oriole, Great-tailed Grackle, and House Sparrow. A real standout was the colorful Green Jay (Cyanocorax luxosus), yet another tropical Central American species found north only as far as the Lower Rio Grande Valley.
“We were unlucky not to find a campground at McAllen, so we went on to Bentsen State Park where we got a camp spot. After a sauerkraut supper, we birded till dark, then showered and wrote up the log. Very hot today.”
Bentsen-Rio Grande Valley State Park, like the Santa Ana National Wildlife Refuge, is located along the Rio Grande river and features dense subtropical riparian forest that grows in the naturally-deposited silt levees of the floodplain surrounding several lake-like oxbow resacas. Montezuma Bald Cypress (Taxodium mucronatum) is a native specialty found there but nowhere north of the Lower Rio Grande Valley. During our visit, we marveled at the epiphyte Spanish Moss (Tillandsia usneoides) adorning many of the more massive trees in the park. Willows lined much of the river shoreline.
Over time, flood control projects such as man-made dams, drainage ditches, and levees have impaired stormwater capture and aquifer recharge in the floodplain. These alterations to watershed hydrology have resulted in drier soils in many sections of the Lower Rio Grande Valley’s riparian forests. Where drier conditions persist, xeric (dry soil) scrubland plants are slowly overtaking the moisture-dependent species. As a result, the park’s woodlands are composed of trees with a variety of microclimatic requirements—Anaqua (Ehretia anacua), Cedar Elm (Ulmus crassifolia), Texas Ebony (Ebenopsis ebano), hackberry, mesquite, Mexican Ash (Fraxinus berlandieriana), retama, and tepeguaje are the principle species. The park’s subtropical Texas Wild Olive (Cordia boissieri) grows in the wild nowhere north of the Lower Rio Grande Valley.
While a majority of birders visiting Benten-Rio Grande State Park come to see the more tropical specialties of the riparian woods, searching the brushy habitat of the park’s scrubland can afford one the opportunity to see species typical of the southwestern United States and deserts of Mexico. This scrubland of the Lower Rio Grande Valley is part of the Tamaulipan Mezquital ecoregion, an area of xeric (dry soil) shrublands and deserts that extends northwest from the delta through most of south Texas and into the bordering provinces of northeastern Mexico.
Our campsite was located in prime birding habitat. We were a short walk away from one of the park’s flooded oxbow resacas and vegetation was thick along the roadsides. It was no surprise that the place abounded with birds. An evening stroll yielded Plain Chachalaca, White-winged Dove, Mourning Dove, White-fronted Dove, Golden-fronted Woodpecker, Brown-crested Flycatcher, Green Jay, Altamira Oriole, Great-tailed Grackle, and Bronzed Cowbird (Molothrus aeneus). At nightfall, we listened to the calls of an Eastern Screech Owl (Megascops asio), Common Nighthawks, and Common Pauraque (Nyctidromus albicollis), a nightjar of Central and South America that nests only as far north as the Lower Rio Grande Valley. The Common Pauraque is the tropical counterpart of the Eastern Whip-poor-will, a Neotropical migrant that nests in scattered forest locations throughout eastern North America.
I would note that we saw no “snowbirds”—long-term vacationers from the northern states and Canada who fill the park through the cooler months of fall, winter, and spring. They were gone for the summer. But for a few other friendly folks, we had the entire campground to ourselves for the duration of our stay.