Aging and Reproduction: Comparative Endocrinology of the Common Tern and Japanese Quail

SYNOPSIS. The endocrinology of reproductive aging in avian species has been described primarily in captive domestic birds, such as the Japanese quail (Coturnix japonica), which show major changes in hormones and reproductive performance. To explore reproductive aging in longer-lived avian species, longitudinal studies are being conducted on the Common Tern (Sterna hirundo) in which age-related changes in nesting patterns and clutch size have been monitored. However, little information is available relevant to endocrine status of breeding pairs of Common Terns. This review summarizes information pertinent to the breeding biology and endocrine status of the Common Tern during reproductive aging and compares these findings to data available from the Japanese quail. Fundamental mechanisms in the process of aging in avian species may become apparent in the comparison of these data and data from field species.