Wintering Warblers - A Warning

In year's past Yellow Warblers were exceedingly uncommon in Texas in the winter season. There would always be that odd one or two in the extreme lower Rio Grande Valley, but by in large they were absent until returning in the spring. Of course there are those warbler species that winter here at the northern fringe of their wintering range (Black-and-white, Black-throated Green, Wilson's, Ovenbird, Northern Waterthrush), but Yellow, for the most past, has not been among this group.

In the past several years this has changed. Now Yellow is being seen regularly in winter as far north as the Coastal Bend (see Ebird map). This year there have been several along the central coast, including one in Port Aransas at the Turnbull Birding Center and four at Hans Suter Park in Corpus Christi. There have also been several Rose-breasted Grosbeaks, with one seen as far north as Galveston. So what gives?

As most CBC participants are aware, there are good years and there are bad years. There are years when there are volumes of lingering migrants, and there are years when you couldn't buy one. But when we look across the vagaries of these annual fluctuations, it does appear as though there are increasing numbers of neotropical migrants that are short-stopping their flights to the tropics to spend the winter season along our coast.

The difficulty with assessing the concepts of global warming as applied (not theorized) is in finding tangible evidence of its impacts. Sea level rise in Texas? No problem. Melting ice shelves and glaciers? Got 'em. Rising mortality in coniferous (boreal) forests? No doubt. But what about these seemingly insignificant scraps of evidence such as lingering neotropical migrants or tropical species (Couch's Kingbird, Green Jay, Greater Kiskadee, Clay-colored Thrush) pushing north? Aren't these just as important in piecing together the global effects of temperature changes?

Texas is on the frontier of this work. By being positioned at the doorstep of the tropics, slight changes in northern ranges in bird species are felt here first. This is precisely why it is critical to collect as much information on these wintering birds as possible, including being sure that the data related to these sightings are entered into a repository such as eBird. Yes, it is great fun to find a rarity out of season (such as the recent Swainson's Thrush). But this find may also provide evidence of a much more significant change afoot, one that will ultimately impact us all, feathered or not.

Of course you can contribute to piecing this puzzle together. Enter your sightings, not matter how brief or (to you) insignificant into Texas eBird. The combined efforts of thousands of birders are critical to documenting these changes at the landscape scale. Spend the time necessary to correctly document and identify these lingerers (isn't it amazing how many species one can turn an Orange-crowned Warbler into?). Finally, follow these lingering neotrops throughout the season. Some are late fall migrants, but many are true winter residents. The trends in those that actually remain here for the entire winter could be a critical study.

Bird Diversity Lessens Human Exposure to West Nile Virus

Biologists at Washington University (St. Louis) have demonstrated that the more diverse a bird population is in an area, the less humans have a chance of being exposed to West Nile Virus WNV). "The bottom line is that where there are more bird species in your backyard, you have much lower risk of contracting West Nile Fever," said Brian Allan, doctoral candidate in biology in Arts & Sciences at Washington University in St. Louis.

"The mechanisms are similar to those described for the ecology of Lyme disease. Most birds are poor reservoirs for West Nile Virus, and so mosquito bites taken on them are 'wasted' from the perspective of the virus. Where many bird species exist, very few mosquitoes get infected, and so we humans are at low risk. A few bird species are highly competent reservoirs, and these tend to occur in urbanized and suburbanized areas where bird diversity suffers."

The characteristic reservoir species in urban situations are Amercan Crows, grackles, House Finches, Blue Jays, House Sparrows, and American Robins (with the robin being the most prolific carrier of WNV). Robins are acclimated to humans, and by feeding on the ground are relatively easy prey for mosquitoes.

The bottom line of this study is that even in urban and suburban situtations, human health is positively impacted by a healthy, diverse bird population. A more detailed explanation of the finding are available on the Washington University in St. Louis website.

Salt Cedar - More Beneficial Than Once Thought?

Recent University of Arizona research shows that salt cedar is not the evil invader once thought. According to the researchers, "what we and scientists at other universities have done is a total rethink on the specific ways plants use water, and how you manage it...We did have resistance at first, and the restoration community has been slow to change their minds about this, but eventually the story gets out. That's why science still does drive these processes. Eventually the practices catch up to the science."

"We've sort of gone full circle from the saltcedar being added to the landscape, then being regarded as a nuisance, and now being recognized for its value."

Ike Impacts on Galveston Bay Oyster Reefs

According to Texas authorities, at least 60% of the oyster reefs in Galveston Bay have been destroyed by the effects of Hurricane Ike. Reefs have been covered by debris and sediment churned up by the storm, and grass and other vegetation scoured from Bolivar now blanket reefs in East Bay. Similar impacts have been reported from coastal Louisiana. Combined, Texas and Louisiana produce 60% of the total domestic oyster supply in the U.S.

From the perspective of bird conservation, there are a number of issues to be considered. First, the impact on oyster reefs by Ike is evidence of much broader damage to the bay system in general. According to Houston Audubon Society's Winnie Burkett, North Deer Island (the largest natural island left in the bay, and home to 40,000 birds of 17 different species) lost a third of its vegetation. Because of debris, Audubon Society members have not been able to get a boat to Evia Island (an island constructed of dredge materials) that, in 2001, was home to 3,000 birds, including terns, Black Skimmers, and Brown Pelicans. How these colonial nesters will fare once breeding season arrives (and many return from wintering in south Texas and Mexico) remains to be seen.

Second, what about specialists such as the American Oystercatcher that depends on healthy oyster populations for their survival? The oystercatcher has never been common in the Galveston Bay system, with this isolated population never exceeding (in my opinion) a couple of hundred individual birds. Combined with the direct impacts of the storm surge on their breeding beaches, what are the remaining oystercatchers going to eat as the bay slowly recovers from Ike's insults?

Finally, we are all optimistic that the oyster population will recover with time. But what if their situation is further compromised by expanded resort development on the west end of the island? For example, the pending Marquette project proposes thousands of new homes on the west end, each with boats and their accouterments (canals, marinas, boat houses). Each boat in Galveston Bay will churn up additional sediments that are already suffocating these reefs. The USACE is now considering a request for a comprehensive environmental impact study concerning any additional development on Galveston's west end. To ignore Ike's impacts, I believe, would be unpardonable. Ike is the third most damaging hurricane in American history, and all involved in west end development, particularly the USACE, must recognize that fact.

See more about the plight of Galveston Bay oysters in this Houston Chronicle article. Also, read the testimony from the Galveston Bay Foundation at a recent legislative meeting in Galveston addressing these same issues. Finally, you can send your comments about the proposed Marquette project to the ACOE at their website. Please ask that the Corps conduct a cumulative environmental impact analysis on further development (including Marquette and Anchor Bay) on Galveston Island.

Ted Eubanks

TBCA Old News, New News

The Texas Bird Conservation Alliance (TBCA), an ad hoc group of organizations and individuals interested in the conservation of Texas birds, last met in February 2008 in McAllen. That daylong session, held to correspond with the Partners in Flight International Conference, brought together a broad range of conservationists who dedicated the day to discussion Texas bird conservation issues. People left that meeting expecting a quick follow up on the next steps to be taken in the evolution of the TBCA.

Few of us expected to be still waiting, almost one year later. The reasons for the delay are complicated, but the simple truth is that any effort of this sort needs to gather a critical mass of interest and effort in order to move forward. Where we may have interest, in effort we have lagged.

Therefore I have decided to revisit this issue, and to begin to organize this effort in the blogsphere. Of course I have every intention of evolving to a more tangible form, but for the moment this is the perfect medium for pulling together those interest in this issue. With the Texas legislative session underway, and the coast still reeling from Hurricane Ike, the need for the TBCA has never been more acute.

For those interested in being involved, I suggest starting by simply subscribing to this blog. Over time we will build a community of bird conservationists in Texas that will have a physical presence. For now, though, this blog will allow us to jump start the effort and see how we might make up ground toward the promise so vividly exhibited last February.

To that end, I am (finally) making available the podcasts of last year's sessions. There may be accessed by simply clicking on the links below. Thanks for your patience and understanding, and I look forward to seeing how far we might push this effort together.

Ted Eubanks

February 2009 TBCA Conference
McAllen, Texas

Podcast 1
TBCA Introduction - Ted Eubanks

Podcast 2
Questions for Ted Eubanks

Podcast 3
GCBO - Cecilia Riley
ABA - Dr. Richard Payne
Audubon Texas - Andy Kasner
Houston Audubon - Winnie Burkett

Podcast 4
TNC - Rich Kostecke
TPWD and BBS - Brent Ortego
eBird - CLO (Chris Wood)

Podcast 5
Valley Nature Center - Martin Hagne
Future of TBCA Discussion