Delta Journal
by Bob Thomas

Locals are familiar with “white canal birds,” those large wading birds that we frequently see around our open drainage canals. There are several species, but the easiest to identify is the Snowy Egret (Egretta thula). It stands two feet tall, has solid white feathers, a black bill, and black legs with yellow toes. The toes are so obvious that they make one shout “Hey, look at those yellow shoes!”

The color contrast between black legs (including the forward directed tarsi) and yellow toes is not accidental and serves a vital function for the bird. Snowy egrets use several types of foot movements during prey capture. They might vibrate the leg and foot, drag a foot over the substrate, probe the substrate, or stomp the foot up and down. All of these serve to startle potential prey, including crawfish, insects, snakes, fish, molluscs, and frogs. Sometimes they run about and grab their prey, other times they are patient stalkers. One peculiar behavior they have is called bill-vibrating, whereby they place their bill in the water and rapidly open and close it, thus scaring and confusing critters swimming in the area.

Snowy egrets are colonial nesters, aggregating in rather dense wetlands where their flimsy nests are loosely constructed. They normally lay two to six pale bluish-green eggs, each about two inches long.

Now rather common, these egrets were on the brink of extinction around the turn of the century. Their nuptial plumes, called aigrettes, are recurved and give the birds a lovely, lacy appearance. This was not overlooked by hat-makers, and the pressure to supply the decorative feathers caused unbelieveable poaching of the species. The passing of the Lacey Act in 1909 and the founding of the National Audubon Society and its early game warden program saved the species. Some populations found themselves in trouble in the 1960s from reproductive failure due to ingestion of DDT and its by-products interupting the calcium cycle, leading to brittle eggs that cracked before hatching. The banning of DDT in the U.S. has again saved the fish-eating birds.

The next time you see white canal birds, see if you can identify the Snowy Egrets in the crowd. If you do, be sure to yell, “I like your yellow shoes!”