Reproduction and Survival of Female Mallards in the St. Lawrence River Valley, New York

Abstract

Few studies of mallards (Anas platyrhynchos) have been conducted in northeastern habitats where mallard populations have increased in abundance since the 1960s and dominate many breeding communities of dabbling ducks. We investigated the breeding ecology of female mallards within the St. Lawrence River Valley (SLRV) of northern New York, from March to july 1990-92, to determine factors affecting reproductive success and survival. Nest success (x = 18%, n = 67) was highest (P < 0.10) in haylands (39%), followed by wetlands (14%), grasslands (8%), and shrublands (3%); predation caused 92% of nest failures. Hen success averaged 18% (n = 84) and was 25% (n = 44) for after-second-year (ASY) females and 11% (n = 36) for second-year (SY) females. Daily survival rate (DSR) of radio-marked females was lower (P = 0.009) during the breeding season (DSR = 0.996, SE = 0.0009, n = 94) than postbreeding season (DSR = 0.999, SE = 0.0007, n = 66). At least 33% of female mortality occurred at nest sites, and avian predators accounted for 6 of the 15 females killed during the breeding season. Estimated brood survival from nest to water was 0.92 (95% CI = 0.85-1.0, n = 13). Management of mallards in the SLRV should focus on maintaining an agricultural land base and protecting wetlands