Dried-up streams and lack of local rainfall around the Aransas National Wildlife Refuge have made its estuaries and marshlands too salty for the blue crabs that the birds depend on to survive.

The drought has also wiped out the berries, worms and insects that they eat.

Whooping cranes are America’s tallest birds and were once a common sight across parts of the country.

But by the 1940s, the use of the pesticide DDT and habitat loss wiped out all but 14 of the birds.

Careful breeding has restored the population to about 400 in the wild, but the population is still sufficiently low that shootings, drought and other factors can pose a dire threat to the species' survival.

Two of the cranes were killed by gunshots in southwestern Louisiana this winter, while another of the birds was shot during late December in southern Indiana.

Photo: Amy Farrier - Flickr