Tongue-Fluttering by Snowy Egrets (Egretta thula) Foraging in a Tidal Estuary

Foraging behavior of Snowy Egrets (Egretta thula) was studied in a tidal estuary in the northeastern USA over a three-year period. Among all observations of egrets foraging (n = 1,223), 8.4% were of “tongue-fluttering', a foraging technique in which an egret inserts the tip of its bill into the water surface and flutters its tongue so that a stream of ripples is generated. Tongue-fluttering was usually practiced when the bird stood in deep water and oriented downstream to produce an expanding ‘V’ of ripples. Limited observations suggested that the ripples attracted small fish and that the egrets had high capture success. Multiple observations suggested that egrets feeding simultaneously by tongue-fluttering distributed themselves in echelon formation, so that downstream birds were located near to ripples generated by upstream birds. These observations provide new information on tongue-fluttering, show that it is locally frequent in a tidal estuary, and suggest that Snowy Egrets practicing this technique can catch fish at rates comparable to those that have been reported for other foraging techniques.