Galveston in the spring, especially during a narrow band of time starting in mid-April, is at the center of the birding world. Migrating songbirds crossing the Gulf of Mexico arrive on Texas shores tired and in need of rest after flying 500 miles from Mexico’s Yucatan Peninsula or somewhere in Central America.
When they arrive each year, birdwatchers are waiting in droves for the brief migration spectacle before hundreds of species of songbirds take off for their northern breeding grounds.
“I run a south Texas trip every year in February and a west Texas trip in March,” said Jim Stevenson, founder of the Galveston Ornithological Society and a popular bird guide. “But every April, where else would I want to be except Galveston?
“It’s the wheelhouse of spring migration.”
In years past, scientists could only guess at the number of those migrating birds, drawing on information from surveys conducted along small portions of the 1,680-mile Gulf shoreline. But that’s no longer the case, as a study by the Cornell Lab of Ornithology announced this week.
Combining data from citizen scientists collected on a worldwide online database called eBird with weather radar data, Cornell researchers can now say with confidence that more than 2 billion birds cross over every spring, with a significant number landing on the shores of Galveston County.
The data also reveal when birds migrate and what routes they take, with the timing of peak spring migration consistently falling within the 18-day period from April 19 to May 7 and 1 billion birds passing over the Gulf in that time span. More of those birds land in Galveston County and Texas locations farther south and west than in the area stretching from Louisiana to Florida, according to study findings.
That observation is consistent with Stevenson’s experience, as are Cornell findings that the earliest seasonal movements are starting sooner, advancing about 1.5 days per decade because of global warming, Stevenson said.
These findings can provide important information that will allow researchers to assess long-term implications of climate change for migratory birds and other living creatures, the Cornell scientists said.
“It kind of makes sense,” Stevenson said. “If the Earth is getting warmer — and everybody but Donald Trump knows that — if you’re a bird, you’re going to want to get to the prime breeding habitat as early as you can. If the Earth is warming, you have to get there a little earlier.”
Birdwatchers in the Galveston area no longer see nearly the number of migrating birds in the second half of May that they saw in previous decades, Stevenson said.
“In the first half of May, nowadays, you get just a few really good days,” he said.
Peak viewing once occurred about April 21 but now is more likely to fall about April 18, Stevenson said.
FeatherFest, Galveston’s annual birding and bird photography festival, celebrating its 17th year, is organized around what are expected to be peak birding times in conjunction with the Easter holiday.
This year’s festival will be April 11 to 14, said Greg Whittaker, a board member of the Houston Audubon Society and founder of the Galveston Audubon group.
“The timing of peak viewing is a little more erratic and probably has to do with shorter-term weather events, like when a cold front comes in,” Whittaker said, citing three weather events last spring that created fallouts of birds, blowing them about in cold winds and leaving them exhausted and in need of rest.
“They kind of drop out of the sky to eat for a couple of days before moving forward,” he said. “It’s a good time to see huge diversity.”
Whittaker is one of legions of birders recording sightings on the eBird site, www.ebird.org, contributing to Cornell’s research. Birders from anywhere in the world can record sightings and post photos on the site in 30 languages, logging where, when and what they saw. The free and open access database has listed a half-billion sightings so far, specifying sites where particular species have been spotted and exactly when.
Of Texas counties ranked as hotspots on the site, Galveston County ranks number four.
Birds are unrivaled indicators of the environment, the Cornell scientists argue.
Mapping their populations and movements more accurately will provide invaluable data as the Earth and seas grow warmer, creating dramatic environmental shifts.
“We don’t know what the result of this climate change will be,” Stevenson said. “But all through history, animals have gone extinct.
“Birds have within their genetic mechanism the ability to change and adapt to a changing world, but if the change takes place faster than they can adapt, then they are at risk.”