Influence of radio packs on captive mallards and blue-winged teal

Back-mounted radio packs of three weights were attached to 30 captive mallards (Anas platyrhynchos) and 30 blue-winged teal (A. discors), and physical condition of the birds was evaluated for 12 weeks. All groups with radio packs lost more weight than did control groups. Feather wear often followed by skin irritation occurred in the axillary region of the wings on 90 percent of the treated birds within 1 week, and on the backs of 55 percent of the treated birds within 4 weeks after the radio packs were attached. The treated birds appeared preoccupied with the radio packs and exhibited a partial aversion to swimming.