The Populations, Breeding Biology, And Environmental Relations Of The Black Duck, Gadwall, And Blue-Winged Teal At Pea And Bodie Islands, North Carolina

A two-year study was made of the nesting ecology of the black duck (Anas rubripes Brewster), the gadwall (Anas strepera Linnaeus), and the blue-winged teal (Anas discors orphna Stewart and Aldrich), at their southern nesting limits along the Atlantic coast. Approximate production at Pea Island was: 1959-black duck 230, gadwall 348, blue-winged teal 105; 1960-black duck 144, gadwall 457, blue-winged teal 97. Production at Bodie Island, estimated only for 1960, was: black duck 111, gadwall 28, and blue-winged teal 48. The major rearing areas were the two man-made fresh-water impoundments on Pea Island (1020 acres of water and marsh) and the brackish pond on Bodie Island (500 acres water and marsh). Estimated juvenile mortalities were: black duck 31%, gadwall 48%, and blue-winged teal 23%. Major predators were feral cats (Felis domesticus) and snapping turtles (Chelydra serpentina). Comparison between the North Carolina coastal marshes and the mid-western duck-producing marshes revealed a striking vegetative similarity. Stabilization of the water levels at Pea and Bodie Islands, by impoundment, has increased this habitat similarity and apparently been of great importance in determining the location and success of the North Carolina gadwall colonies, which are disjunct by 1600-2200 miles from the major nesting areas of this species. The conditions supporting fairly high densities of nesting black ducks and blue-winged teal at the southern limits of their breeding ranges appear to be improved habitat and protection. The breeding- biology of all three species was observed to be basically similar in North Carolina to that recorded for these birds in their major nesting regions.

Publication date
Starting page
53
Ending page
67
ID
65515