A Deficient Diet Narrows Growth Bars on Induced Feathers

Abstract

Short Communications 725 vegetation to older stands with more complex vege-tative structure. Thus, we found no support in the undamaged portion of the study area for the hypothesis that site occupancy by the sparrow increased with age of the clear-cuts. The high proportion of clear-cuts occupied by sparrows in the hurricane-damaged Witherbee District is similar to the pattern of occupancy in regions where mature pine stands are very rare (Dunning and Watts 1990). The pattern in the undamaged Wambaw District , where no sparrows were seen in clear-cuts, is similar to the habitat occupancy found in other South Carolina areas where mature pine is common (Dun-ning unpubl. data). Thus, one major effect that Hurricane Hugo may have had on the sparrow was to change the local pattern of habitat use. If mature pine and clear-cut habitats yield different levels of reproductive success or survivorship, such a change in habitat occupancy could have a long-term effect at the population level. The impact of large-scale catastrophes such as hurricanes has been documented recently for species whose habitat requirements are relatively well described (Engstrom and Evans 1990). We suggest that species, such as Bachman's Sparrow, whose habitat requirements are less understood should also be monitored to determine the ultimate effect of the hurricane on local avian populations.