Birding Big Day in the Lower Rio Grande Valley

Thick mist rolled off the spiny limbs of unfamiliar tropical vegetation as strange calls pierced the stillness of the early morning.  We crossed over a small channel of water, watching for green kingfishers, and then walked into the woods on the other side.  Large oak branches draped in Spanish moss hung over the trail.

We were at the famous Santa Ana National Wildlife Refuge, located in the very southern tip of Texas.  Birding at Santa Ana and other locations in southern Texas had been a long awaited dream for me, and it felt unreal that it was finally happening. My friends and I were participating in the Rio Grande Valley Birding Festival (RGVBF), and had scheduled this day to be a “big day,” an attempt to see as many species as possible in 24 hours.  We had all agreed in advance that we would be extremely relaxed about the pace, as we wanted to have as much time as we wanted with each new species.

As we continued walking through the old, tropical woodland, we heard the calls of great kiskadees, plain chachalacas, long-billed thrashers, and golden-fronted woodpeckers.  Mourning, white-winged, and Inca doves foraged on the ground.  Up ahead the trail opened into a large, wet marsh, called Pintail Lake.  As we walked out on an elevated dike towards the water, we heard American pipits, and spotted a vermillion flycatcher and two tropical kingbirds perched on projecting sticks.  We set down our scopes and started scanning the many ducks on the water.  We quickly found 11 species, including black-bellied whistling duck, mottled duck, redhead, and the lakes namesake, the northern pintail.

As we were about to get back into the cars, a small, gray Buteo flew low over the parking lot and landed in a nearby tree.  It was a gray hawk, a lifer for most of us.

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Gray Hawk (Buteo plagiatus), photo by Theo Staengl

I had never been to our next stop, a small city park called Anzalduas, before, but I had heard it was a good place for zone-tailed hawk.  We drove there on roads on top of high dikes overlooking the Rio Grande.  Border Patrol vans were everywhere, but most just waved at us as we drove past.  When we finally got to Anzalduas, it wasn’t quite what I was expecting.  A far cry from most of the natural areas we were birding in the Rio Grande Valley, Anzalduas was a large expanse of sparse grass under periodically spaced trees, broken only by decrepit playground equipment.  The only other people around were twenty or so border patrol agents.

A local constable drove up and unpleasantly informed us that the road we had driven on into the park was closed to the public, despite the complete absence of signs saying so.  He warned he’d give us a citation next time.   We walked up a side road to another dike, across the park from the Rio Grande that was supposedly a very reliable spot for zone-tailed hawk, and possibly for hook-billed kite.  After several uneventful minutes, two things happened very quickly.  First, I noticed the constable’s car coming up the road toward us, and a large, thin-winged, mostly black raptor, a zone-tailed hawk, flew low over us.  We ignored the constable, and had beautiful looks at the hawk.

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Zone-tailed Hawk (Buteo albonotatus)

When we looked down from the hawk, we saw the constable talking with my mom and our unofficial guide, who knew the local area well.  The constable pointed to two huge signs in front of the road we had just walked up, that said “no public use.”  We had honestly missed the signs because we had approached from the side, but from the constable’s perspective it sure looked sketchy.   In the end he let us go, and we hurried quickly off the dike.  The only other notable bird we saw at Anzalduas was a house finch, locally uncommon in the Rio Grande Valley.

Forty minutes later, we pulled into the gravel parking lot of the Frontera Audubon Center’s small tropical reserve.  We walked the short, dirt trails through dense undergrowth, scanning the bushes around us for warblers and clay-colored thrushes.  As we neared a small feeder station near the visitor center, we found our first thrush flock, with about five clay-colored thrushes.

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The range of the clay-colored thrush (Turdus grayi) just barely extends into the United States in the very southern tip of Texas.  Clay-colored thrushes and many other predominantly central American species that just extend into the southern Rio Grande Valley are what makes south Texas such a birding hotspot.  These species are often referred to in the US as Rio Grande specialties, even though many of them are much more abundant further south.

We continued on the trails deeper into the woods, listening and looking for warbler activity.  That morning, someone had spotted a tropical parula there, which would be a life bird for all of us.  Soon we came to a wooden platform overlooking a small lake.  Warblers, mainly orange crowned, chipped and flitted in the dense willows.  We scanned the flock to the best of our ability, and were able to add Nashville, black-and-white, and black-throated green warblers to our day list.  We spent another hour roaming the trails looking for the tropical parula, but it proved to be a waste of time.  I was able to photograph a buff-bellied hummingbird, another fairly range restricted species, at one of the feeding stations, though.

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Buff-bellied Hummingbird (Amazilia yucatanensis)

As we got out of the car at Estero Llano Grande State Park, I was beginning to feel worried we had spent too much time at Frontera, and we wouldn’t have enough day-light at South Padre Island, an important shorebird spot, later in the day.  Evan so, I couldn’t help enjoying the bountiful ducks at the visitor center lake at Estero.  Wild ducks swam peacefully about, clearly used to humans being nearby.  A vermillion flycatcher foraged from a dead stick over the marsh, its brilliant red belly and crown contrasting beautifully with its brown back and eye-line.  We added cinnamon teal and least grebe to our day list.  One of the birds I was personally most excited to see here was the common pauraque, a large tan nightjar of Central and South America.  While it is locally extremely common in south Texas, it is so cryptically patterned that one could easily walk within a foot without seeing it.  We were walking along a dusty dirt road near where pauraques have been known to roost when I almost stepped on one.  Once we noticed it, we were so focused on photographing it, we failed to see two others within a yard of it until some kind older birders pointed them out.  What a weird looking bird!

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Common Pauraque (Nyctidromus albicollis)

We raced along the highway as the sky became cloudier and the sun sank ever lower toward the horizon.  Our rental car’s tinted windows probably did not help our feeling of impending darkness.  When we stepped out of the car at the mudflats above the South Padre Island Convention Center, wind coming off the Laguna Madre buffeted us and tore at our clothing and scopes.  We hurried over the muddy sand toward distant shorebird flocks, hoping the incoming tide wouldn’t strand us.  As soon as we could, we put down our scopes and started scanning.  We quickly found most of the common shorebirds we needed, along with two piping and snowy plovers.  It was only the second time I had ever seen a snowy plover, and it was a lifer for some of my friends.  We ran back to the cars across what were now inches of water, soaking our shoes.  We spent the rest of the daylight birding around the slightly more sheltered trails of the convention center.  Our list for the day was 126 species, the most I have ever seen in a day.

 

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