Birds are Creeping Northward
by Ro Wauer
During the last ten to twenty years we have seen increasing numbers of tropical bird species in the Golden Crescent. Species such as green jays, buff-bellied hummingbirds, green and ringed kingfishers, golden-fronted woodpeckers, white-tipped doves, great kiskadees, Couch’s kingbirds, cave swallows, and bronzed cowbirds have all been found on a regular basis. Most of these were considered only Mexican or at least Lower Rio Grande Valley birds until recent years. I remember visiting the Valley in the late 1960s to see many of these because they were not known any elsewhere in the United States. My first ever buff-bellied hummingbird was found at the home of a Valley fruit-grower. It could be expected nowhere else in the U.S.; now it is a full-time resident in the oaks growing around my home in Mission Oaks.
This northward movement of the breeding grounds of many birds is well documented, although this shift also is likely for many other groups of wildlife. Butterflies also are experiencing the same kind of movement, but their northward shift is far less understood than it is for birds. Although individual species of southern butterflies have been recorded in our area in recent years, proving population shifts is more difficult because they are subject to accidental dispersions from various weather patterns.
In a recent article in the newsletter of the Gulf Coast Bird Observatory, author John Rappole states that “at least 80 species of birds native to tropical, subtropical, or warm desert habitats have shown evidence of northward or eastward extension of the breeding distribution into, within, or beyond the borders of South Texas. These changes range from a few to several hundred kilometers and occurred over a relatively brief time period (decades)!” Rappole continues: “These changes are in line with regional climatic warming and possible drying…If predictions are correct, over the next century climate change will have an ecological effect roughly similar to moving the region 100 miles to the southwest.”
From an optimists’ point of view, assuming that the northward movement continues, the Golden Crescent could possible add a substantial number of bird species to our list of full-time residents. What are some of the species that we might expect in the near future? How about some parrots? A couple kinds of parrots have already resided in the Golden Crescent – probably escapees - but were unable to maintain a viable population for more than a few years. And Harris’ hawks; groove-billed anis; ferruginous pygmy-owls; lesser nighthawks; beardless flycatchers; verdins; black-crested titmice; black-tailed gnatcatchers; tropical parulas; long-billed thrashers; black-throated, Botteri’s and olive sparrows; hooded and Aububon’s orioles; and lesser goldfinches already occur in nearby counties to the south and/or southwest. It would not surprise me at all to find these birds nesting in the Golden Crescent; some already may.
The obvious follow-up question might be: with the climatic changes in our area that are likely to increase our list of breeding birds, what species that are currently nesting here might we loose? Probably not many or none at all. The waterbirds, including waterfowl, waders and shorebirds, should remain the same. We do need to worry about the changes in the blue crab populations along the coast; it is possible that we could loose the already endangered whooping cranes. And maybe our small population of Mississippi kites that currently are at the southern edge of their range might decline. This also may be the case for red-bellied woodpeckers, Swainson’s warblers, orchard orioles and a few other species.
Mother Nature is one fickle lady!