Mate changes by black-bellied whistling ducks

Delacour and Mayr (1945) suspected that whistling ducks (Dendrocygnini) kept the same mate for life. Bolen (1971) confirmed that Black-bellied Whistling Duck (Dendrocygna autumnalis) pairs remain together from year to year and reported one pair that had nested together for at least 4 yr. My recapture records of birds banded at nest boxes indicate that Black-bellied Whistling Ducks will pair again when their mate dies; here, I describe two occurrences in which both members of pairs obtained new mates, although their previous mates were still alive.