COMPARATIVE DEVELOPMENT IN CAPTIVE AND MIGRATORY POPULATIONS OF THE BARNACLE GOOSE

The development of the locomotory muscles and associated skeletal stru ctures of goslings and adults from a captive population of barnacle ge ese (Branta leucopsis) was compared with that from a wild migratory po pulation. There was no significant difference between flight-muscle de velopment of wild and captive goslings up to 7 wk of age, when the bir ds are first able to fly. In contrast, mass-specific citrate-synthase activity in the semimembranosus leg muscle of the captive goslings was significantly lower than that of wild goslings by 5 wk of age. During the postfledging premigratory period, captive geese showed significan tly higher values for both mass and mass-specific citrate-synthase act ivity of the leg muscles than those of wild birds. Premigratory wild g eese had significantly higher citrate-synthase activity in the pectora lis muscles and larger cardiac ventricular mass (by ca. 20%-25%) than both wild postmoulting and captive premigratory adults. Total flight-m uscle mass was only slightly reduced (by ca. 10%) in long-term captive adults compared with wild premigratory adults. Most of the difference s between these two populations appear primarily to reflect their rela tive levels of activity and/or differences in their ambient environmen t, rather than any intrinsic differences in developmental or adult phy siology.