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Migration - Still Great In May!
by Mary Beth Stowe (alamoinn@aol.com)
published June 2017

The most popular time to come to the Lower Rio Grande Valley in order to catch spring migration is the last two weeks in April, and not without good reason! One can catch the tail end of the hawk migration (hawk watches generally end around mid-April), shorebirds are coming into their breeding finery, and colorful, fanciful warblers are coming through in good numbers. And because May is such a prime migration month in northern states (such as my native Michigan), most folks think that "the show is over" in the Valley by the end of April.

Not so! In fact, if you check John Arvin's excellent Birds of the South Texas Brushlands (a bar-coded checklist available from Texas Parks and Wildlife, and downloadable as a PDF file), you'll see that the peak times for most of the warblers is mid-April through mid-May, and the flycatchers come through primarily during the entire month of May! Other songbirds that reach their peak in early May include Philadelphia Vireo, Veery, and Gray-cheeked and Swainson's Thrush. And besides many of the common and widespread warblers that are still coming through, the first two weeks of May still offer chances at bagging treasures such as Blue-winged, Golden-winged, Chestnut-sided, Magnolia, Blackburnian, Bay-breasted, Blackpoll, Cerulean, and Kentucky Warblers, while two species (Mourning and Canada) are primarily May migrants!

Some shorebirds (such as Hudsonian Godwit and White-rumped Sandpiper) focus their passage during May, and many shorebirds are still moving through throughout the month (and are prettier to boot). Some migrant hawks, such as Mississippi Kite and Swainson's Hawk, continue well into May, and Black Tern reaches its peak at this time as well. Breeding birds such as Yellow-billed Cuckoo and Groovebilled Ani are much easier to find (Bentsen Rio Grande State Park and Santa Ana NWR are good places to look), and the local Botteri's Sparrows are beginning to arrive, which can be very tough to find in April; look for them, along with Cassin's Sparrows, along Old Port Isabel Road, SR 186 (Sacahuistale Flats), Boca Chica NWR, and Palo Alto NHS. Besides the migrants, our specialty species are always around to delight and entertain: Chachalacas are chorusing and chasing each other, and happening upon a family with the adorable youngsters is always a treat!

Many of the more skulky species, such as Long-billed Thrasher and Olive Sparrow, are singing openly and can be much easier to see. While many of the parks quit feeding around mid-March, others continue to stock their feeding stations (e.g., the National Butterfly Center, Quinta Mazatlan, Sabal Palm Sanctuary, and Frontera Audubon Thicket, among others), so the visitor coming to the Valley in early to mid-May can still enjoy the antics of Great Kiskadees, Clay-colored Thrushes, White-tipped Doves and Green Jays.

With the lowering of the water levels in both Santa Ana and Estero Llano Grande, more shorebird habitat is exposed, and the chances of seeing a rare Purple Gallinule are enhanced. On the Island, Scarlet and her volunteers still put out oranges for the hungry birds during fallout conditions, and the boardwalks provide views of nesting Least Bitterns and Common Gallinules, plus lounging Roseate Spoonbills and maybe even a lingering Redhead or two. And there's always the possibility that a wintering Common Loon or even a Lesser Black-backed Gull may be still hanging around (and speaking of Scarlet, you can always arrange to have her take you out to see the Mangrove Warblers, found nowhere else in the United States, as well as her special dolphins!

Yes, it's starting to get warm, but no warmer than up north. Here it is, mid-May, and I just heard from my friend in Harrisburg, PA, that the high was going to be 90° there! Do your birding early in the morning and later in the evening (the latter is a good time to visit the parrot roosts), be sure to "spray up", take plenty of water, and take advantage of the "siesta"!

May is a great time to come to the Valley!