Corticosterone responses of hand-reared and parent-reared grey-faced petrel chicks (Pterodroma macroptera gouldi)

Hand-reared grey-faced petrel (Pterodroma macroptera gouldi) chicks (Order Procellariformes) that were subjected to a standardised blood sampling protocol immediately before they fledged showed a reduced corticosterone response compared to parent-raised chicks. Serum corticosterone concentrations were lower in hand-reared than parent-reared birds 30 and 60 min after handling was initiated (21.5 +/- 6.7 vs. 105.4 +/- 7.4 ng/ml at 30 min, and 11.3 +/- 3.6 vs. 93.8 +/- 11.4 ng/ml at 60 min, respectively). The total integrated corticosterone response and the response corrected for initial corticosterone concentrations were similarly lower in hand-reared than parent-reared birds (927 +/- 489 vs. 4639 +/- 1924 ng/ml.min, and 529 +/- 352 vs. 4110 +/- 1896 ng/ml.min, respectively). Habituation to handling associated with hand-rearing, which is expressed as a subdued corticostrone response, is likely to reduce the physiological stress associated with the translocation and reintroduction of these birds. However, the longer-term consequences of this attenuated response remain unclear. (c) 2005 Wiley-Liss, Inc.