EFFECTS OF SURFACE TEXTURE AND SHAPE ON GRIT SELECTION BY HOUSE-SPARROWS AND NORTHERN BOBWHITE

We evaluated the influence of surface texture and shape on grit select ion by House Sparrows (Passer domesticus) and Northern Bobwhite (Colin us virginianus). Captive birds were given a mixture of two grit types (angular/oblong and rounded/spherical) for seven or 14 days. At the en d of this period, most birds (24 of 30 House Sparrows and 21 of 26 Nor thern Bobwhite) had more angular/oblong and less rounded/spherical gri t (P < 0.01) in their gizzards than predicted on the basis of availabi lity. An improved understanding of avian responses to surface texture, shape, and other grit characteristics may be useful in reformulating granular pesticides to reduce their attractiveness to birds.