The Nature Writers of Texas

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Sunday, July 23, 2006

Fall Bird Migration Already Underway
by Ro Wauer

It annually seems strange that in July we already are finding southbound migrants passing through our area. It was only a few weeks ago that those same birds were passing through South Texas on their way to their nesting grounds to the north, some as far away as Alaska and above the Arctic Circle. Yet here they are, maybe even the same individuals that we saw in late March or April or May, back again. But that is the way of things in the bird world. In fact, many of our earliest southbound migrants are the ones that traveled the furthest to nest on the northern tundra. They nest early, even when much of their nesting ground is still filled with snow and ice. But because of the extremely long daylight hours in the Arctic summers, they are able to raise their brood much quicker than species further south with shorter days. They are able to finish their family chores before the days begin to cool.

Bird species we are seeing in late July and August, the earliest of the southbound migrants, are often males only. The females often are still tied up with family chores, although they and the young of the year too will soon follow the males. Shorebirds, many of which are Arctic nesters, are some of our most numerous July-August migrants. And hummingbird males are famous for their early arrivals. It is not surprising, for example, to find rufous hummingbird males feeding in mountain meadows of the Texas Big Bend Area and the mountains of northern Mexico by early July. Of course, hummingbird males never attend to family business once mating has occurred. Hummingbird males are included among the most notoriously - promiscuous rakes - in the bird world. After mating they gather in bachelor groups, feed on the abundant flowering plants with other males, until they move southward toward their wintering grounds.

Many of our earliest southbound migrants are those that nested nearby. The purple martin is one excellent example. Those that have nested in our own neighborhoods have completed their families and have either moved on toward their wintering grounds or are staging in favorite locations and preparing to head south together in larger flocks. We also are seeing birds that have nested just out of our immediate area and in northern Texas and adjacent states. A few examples of these include a number of swallows, blue-gray gnatcatchers, northern parulas, yellow-throated and black and white warblers, and indigo buntings.

And a few post-nesting birds that nest in Texas roam in directions other than southward. There regularly are records of various southern species being found considerable distances from the nesting grounds. Imagine scissor-tailed flycatchers in the northeastern states, and various hummingbirds moving north or eastward after nesting instead of southward to their normal wintering grounds. One of the best examples is our very own buff-bellied hummingbird that annually is found in Louisiana in late fall and early winter. This is the same species that has become a full-time resident in Victoria County only during the last dozen years. It is reported in spring and summer more and more often to the north of Victoria County, and it would not surprise me that it would soon become a summer resident throughout most of southeastern Texas, and maybe westward into the Austin area.

Buff-bellied hummingbirds are but one of several birds that have moved northward during the last couple decades. Once only Texas residents in the Lower Rio Grande Valley, buff-bellied hummers, green jays, Couch's kingbirds, ringed and green kingfishers, tropical parulas, and white-tipped doves are on the move northward. It is readily apparent to anyone with an open mind that even we along the Central Texas Gulf Coast are affected by Global Warming. In this case, it can be considered a positive affect.

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