RIO GRANDE VALLEY, Texas – The Rio Grande Valley is home to many tropical birds that don’t venture much farther north, but one remarkable species of duck has greatly expanded its range well beyond the banks of the Rio Grande.
It used to be if you wanted to see a Black-bellied whistling duck in the United States then the Rio Grande Valley was the only place you could reliably accomplish this.
Over half a century ago, during the annual Christmas bird count, tabulators for the first time counted 143 of the tropical ducks in the Valley. Now, there are hundreds on this resaca in San Benito, and the Black-bellied whistling ducks have expanded their range northward throughout the eastern region of Texas with occasional individuals documented as far north as Minnesota.
With their coral pink bill, tawny body, black belly and distinctive white wing patch, whistling ducks are strikingly beautiful creatures.
Like White-winged doves and many other avian species, Black-bellied whistling ducks have dramatically increased their range. While the Valley remains the northernmost outpost for a number of tropical species that just barely edge into the United States, whistling ducks are now venturing far from the banks of the Rio Grande.
While global warming undoubtedly has contributed to remarkable change in the range of many species, whistling ducks have also benefited greatly from agricultural practices. They are particularly fond of grain, and frequently visit a nearby silo where they gather shoulder-to-shoulder and beak-to-beak foraging for any available grain.
Their constant whistling chatter, from whence they glean their name, echoes off the metal structure as they vie for scattered kernels.
There is currently no reliable estimate of the whistling ducks population, but there are probably well over 50,000 in the Texas breeding population, and birders will certainly have no problem counting them in the Rio Grande Valley this Christmas.