RIO GRANDE VALLEY, Texas – Flocks of wood storks are arriving in the Rio Grande Valley, and they won’t have scarcity of water to wade as they forage for fish and other aquatic creatures.
Worldwide there are 17 species of storks, but only the Wood stork is regularly found in the United States. Standing nearly four feet tall and with a wingspan of five feet, wood storks are impressive birds.
The black trailing edges of the wings and tail contrast dramatically with their white plumage. However, it is their dark, gray naked head and neck that really sets them apart from other large wading birds.
It is thought that their featherless heads are an evolutionary adaptation to their feeding style as they slowly stroll murky shallows with their massive 10-inch bills constantly submerged.
Rather than having feathered heads coated in sticky muck their baldness also helps dissipate heat as water droplets evaporate.
Wood storks feed by tactolocation. As they grope with sensitive bills any contact with potential prey results in a rapid reflex that clamps their bill shut in an instant. A stork can snap its bill shut in a mere 25 milliseconds, which is an extraordinary reaction time matched by few if any other birds.
Wood storks derive their name for their propensity to nest and roost in trees, but visitors to deep South Texas are spending most of their time wading shallow resacas in search of sustenance.
They breed along the southeastern Gulf coast, and many visit South Texas during the summer as they migrate southward in search of fish filled shallows. Wood storks have big appetites, and it has been estimated that a nesting pair with two fledglings consume more than 400 pounds of fish in a single breeding season.
While once endangered, Wood storks have made a slow recovery and now number some 8,000 breeding pairs in the United States.