The use of medroxyprogesterone acetate to induce molting in chinstrap penguins (Pygoscelis antarctica)

Molt was successfully induced with a progestational compound, medroxyprogesterone acetate (Depo-Provera), in six of six previously nonmolting chinstrap penguins (Pygoscelis antarctica). The initial treatment consisted of five sequential weekly injections of 30 mg/kg Depo-Provera beginning in early September. Four weeks after completing the injections, the penguins had gained an average of 23% body weight, but none had molted. Beginning early November, five weekly injections were resumed, which initiated molt in all individuals within 34 days following the last injection. Molt was completed by mid-January, nearly 2 wk later. In the following years, nonmolting chinstrap penguins were given a single series of five weekly injections beginning in early November, 2 mo prior to the normal molting period.