Parental Care in Tawny-bellied (Sporophila hypoxantha) and Rusty-collared (S. collaris) Seedeaters

—The genus Sporophila (Emberizidae) comprises species of small finches characterized by marked sexual dichromatism, which in birds is positively associated with extent of female bias in parental care. We analyzed differences in parental care in Tawny-bellied (S. hypoxantha) and Rusty-collared (S. collaris) seedeaters. We video-recorded nest activity during incubation and when young were 2–4 and 7–9 days of age. Females of both species built the nest and incubated the eggs alone. Female Tawny-bellied Seedeaters: (1) incubated 59% of the time, (2) had a higher frequency of nest visits than males when chicks were 2–4 days of age, and (3) their visits were longer because after feeding they remained in the nest brooding the chicks. There were no gender differences in frequency of nest visits when chicks were 7–9 days of age, but visits of females were longer than those of males. Female Rusty-collared Seedeaters: (1) incubated 51% of the time and (2) had a higher frequency of nest visits when chicks were 7–9 days of age. Both males and females brooded chicks and there were no gender differences in frequency and length of nest visits when chicks were 2–4 days of age. Parental care in both species is female biased, but the extent of male care is slightly higher in Rusty-collared than in Tawnybellied seedeaters. Received 4 February 2008. Accept-