Tuesday, February 19, 2013

Texas crane totals not increasing, but flocks now inland offer hope

Whooping cranes in Texas are caught up in a numbers game that produced one encouraging development this year but remains inconclusive overall.

The latest survey results released by the U.S. Fish and Wildlife Service concluded that there were 257 cranes wintering on the Texas Gulf Coast this year and 22 living inland.

In 2011, an actual count of the birds concluded that there were 283, four more than this year's total. All were living on or close to the coast.

The decline is not great, but an increase is what was hoped for.

Noteworthy about this year's numbers is that never before have so many cranes been documented living inland.

One flock took up residence at Granger Lake north of Austin, and another appears to have established itself north of El Campo.

Texas is the winter home to the only self-sustaining whooping crane flock in the world. That diversity of wintering grounds provides insurance against an event such as a hailstorm or oil spill killing the entire flock.

It's great news for those who want to see the species recover.

But for those monitoring that recovery closely, the wildlife service's latest numbers are frustrating.

?By their own analysis, USFWS offers a 95 percent probability that the actually flock size is somewhere between 178 to 362 birds,? said Ron Outen, regional director of The Aransas Project.

TAP is waiting for a ruling on a lawsuit it filed against the state. It argued that the state is over-allocating water from the Guadalupe and San Antonio rivers and thus harming the estuaries that the whooping cranes depend on.

That case hinges on the year-to-year population of the cranes as it relates to fresh water inflows.

Outen argues that with a population of around 300 birds, the Fish and Wildlife Service could get a much more accurate number by simply counting the birds instead of its current method, which uses a statistical analysis based on flight observations over the whooping crane's wintering grounds to reach a total.

?With this methodology, they can't say there are more birds or less birds than last year,? Outen said.

In a news release announcing the new totals, the agency acknowledges that its methodology is not perfect and said it expects the accuracy to improve.

?We expect this process will take several seasons before the obvious and not-so-obvious factors can be incorporated into the survey protocol and statistical models,? the news release states. ?This is how science progresses.?

cmcdonald@express-news.net

Source: http://www.mysanantonio.com/news/environment/article/Texas-crane-totals-not-increasing-but-flocks-now-4286631.php

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