SONGBIRDS DO NOT CREATE LONG-TERM STORES OF CALCIUM IN THEIR LEGS PRIOR TO LAYING - RESULTS FROM HIGH-RESOLUTION RADIOGRAPHY

We prepared high-resolution radiographs of the leg bones of three pass erine species using X-rays at the Cornell High Energy Synchrotron Sour ce (CHESS), which allows imaging with exceptionally high contrast and resolution. In studies of living tree swallows before and after laying and in studies of brown-headed cowbirds and great tits collected befo re, during or after laying, there is no evidence of calcium storage in the leg bones. By contrast, great lit nestlings raised in environment s with extremely low calcium availability exhibited calcium deprivatio n in the development of their leg bones.