Sampling avian adipose tissue: assessing a nondestructive biopsy technique

ABSTRACT.   Adipose tissue samples can provide valuable information about the physiology, foraging ecology, and toxicology of birds. However, despite these varied applications, to date, no procedure for taking adipose samples from live birds has been described in detail, nor assessed for potential adverse effects. We describe a nonlethal method for collecting adipose tissue from adults and chicks of Black-legged Kittiwakes ( Rissa tridactyla ), Common Murres ( Uria aalge ), and Northern Fulmars ( Fulmarus glacialis ), and assess the short- and longer term effects of the procedure. Biopsies were carried out in the field using topical anesthetic and samples were taken from the synsacral region. Only two of 283 birds sampled (0.7%) had too little adipose tissue to be sampled successfully. Thirty-two kittiwakes were recaptured at varying intervals after the procedure (3–50 d) and the biopsy site inspected carefully. No signs of infection were observed and wounds healed completely within 6 d. Compared to birds captured for routine banding, biopsied kittiwakes showed neither greater weight loss nor reduced breeding success in the year of sampling. Similarly, recapture rates of biopsied birds in subsequent years were similar to those of individuals that had been blood sampled or banded. Our results suggest that collecting samples of adipose tissue by nondestructive biopsy has no more effect on birds than taking blood samples via syringe. Thus, we recommend nondestructive adipose tissue sampling via biopsy as an effective alternative to lethal methods in studies of wild birds.