There’s plenty for all at the local watering hole
Published November 5, 2022, in the McAllen Monitor.
Story and photos by Anita Westervelt, Texas Master Naturalist
Lakes, marshes and resacas are teeming with wading birds – some are permanent residents, some visiting for the winter and others just passing through.
Communal feeding groups of spoonbills, egrets, ibises and other waders are around all year; their numbers increase during migration: those from more northern points coming for the winter or continuing on further south for a few months.
Collectively, a group of dissimilar wading birds such as this has only the one descriptive noun: a flock. Individually, each species has its own collective name: a bowl of spoonbills, a congregation of ibises, a stand or heronry of egrets.
Recently, wood storks have entered the mix. These infrequent Valley visitors are a rare but fun sight – a swoop of storks amicably joining the other wading birds. Wood storks are not true migrants, they move in response to food availability, preferring shallow freshwater bodies beginning to dry up where fish are likely to be abundant and easy to catch. Current drought conditions make it easy for them to meet these super-selective body-of-water criteria.
A flock of wading birds works together in the feeding grounds. A phalanx of wood storks converges at the edge of the water, bills down, bodies hunched; the tight muster undulates like a crawling caterpillar, circumnavigating a pond. Wood storks rely on touch to catch their prey.
They forage by walking slowly through the water with their open bill dipped in. They push their feet up and down or flick their wings to startle prey. When they feel or see it, their bill snaps closed in an exceedingly fast reflex.
Great egrets, wading behind the wood storks, benefit from the startled fish swimming within their striking distance. Roseate spoonbills feed in the shallows alongside the storks, sweeping their open spatula-shaped bill from side to side in the water to sift up food while slowly walking forward. Their bill has touch receptors that help it feel its prey. Their nostrils are located at the top of the long, flat bill, which allows the bird to breathe while the bill is under water.
Resident white Ibises are joined by other ibises on their way to the Mexican coast. They search for food in tandem with the spoonbills, probing the bottom with their long, reddish, decurved bill as they wade, also sweeping their bill from side to side.
White ibis eat crabs, crayfish, crustaceans, small fish, mollusks, frogs, worms, spiders and insects, like water bugs, beetles and aquatic insects and their larvae. Great egrets have much the same diet but prefer mostly fish. They also will eat frogs, salamanders and snakes.
Roseate spoonbills eat minnows and other small fish, small crustaceans, shrimp, mollusks, snails and insects, especially beetles along with plant matter that might enter the mix. Wood storks eat mainly fish, crayfish, frogs and large water insects, as well as snakes, baby alligators, small turtles and rodents.
A chorus line of waders might be seen at the water’s edge in the evening, before dispersing to roost in nearby trees for the night.