USE OF VISUAL COVER BY DOMESTIC-FOWL - A VENETIAN BLIND EFFECT

Cover is a structural feature of the environment that animals can use to conceal themselves from predators or conspecifics or to gain shelte r from inclement weather. Cover may also form a physical barrier limit ing movement. It was hypothesized that domestic fowl, Gallus gallus do mesticus, would use visual cover for concealment. Use of cover was exa mined in two strains of domestic fowl kept indoors in four groups of 1 10-112 birds each. In each pen, cover was provided by four rigid verti cal panels, one in each of four quadrants. Four similar quadrants were without cover. To investigate use of cover for concealment, the four cover structures varied in continuity of visual cover: (1) transparent (0% cover), (2) transparent with four equidistant vertical green stri pes (33% cover), (3) transparent with eight such stripes (67% cover) a nd (4) solid green (100% cover). Scan samples of quadrant use were mad e weekly when the birds were 24-52 days of age. Both strains of domest ic fowl (I) used areas with cover more than areas without cover, (2) s howed increased resting and preening behaviour in areas with cover and (3) showed increased use of cover as continuity increased from 0 to 6 7%. These results could not be explained by thermoregulatory or physic al barrier effects of the cover structures. The results are consistent with the hypothesis that a preference for concealment motivates the u se of visual cover by domestic fowl, and suggest a 'Venetian blind' ef fect for visually discontinuous security cover. (C) 1997 The Associati on for the Study of Animal Behaviour.