A MINIATURE CAMERA SYSTEM FOR EXAMINING PETREL BURROWS

Studies on burrow-nesting seabirds are hampered by difficulties associ ated with access to and direct observation of nesting chambers. During a 2-yr study examining the effect of rat predation on Bonin Petrels ( Pterodroma hypoleuca) on Midway Atoll, we developed a miniature camera system that enabled us to view the contents of burrows, assess the st atus of the petrels' breeding activity, and search for evidence of rat predation. We successfully entered burrows and examined 65% of all at tempts. Nine percent of burrows encountered were either too long or co ntained sharp turns. The remaining 26% contained rigid roots that prev ented passage of the camera head. In addition to being small and inexp ensive, the system limited disturbance to birds by using infrared ligh ts and was easy for one person to carry and use efficiently.