High coordination and egalitarian parental effort in the Rufous Hornero

MASSONI, V.; REBOREDA, J.C.; LOPEZ, G. L.; ALDATZ, F.

THE CONDOR

COOPER ORNITHOLOGICAL SOC

Año: 2012 vol. 114 p. 564 - 570

0010-5422

Avian parental care is understudied in temperate southern hemispheric regions, in particular for the Neotropical Furnariidae family. We measured rates of nest building, mudcarrying visits, incubation, brooding, feeding and nest-sanitation behaviors provided by molecularly sexed Rufous Horneros (Furnarius rufus) nesting at the humid pampas of Argentina. We also evaluated the coordination of all these behaviors between the partners, and compared the frequency of uncoordinated behaviors of each sex. Males and females worked highly equitably along the entire nestling cycle with few exceptions: a) both sexes built the nest but males supplied somewhat less mud at the beginning of nest construction, b) though highly involved in incubating the eggs males did so slightly less often than females during early incubation, c) even if males also brooded the nestlings, they brooded less often and for a little shorter periods of time than females, and d) young nestlings were fed less often by males than by females. We found no differences in nest sanitation rates. The proportion of coordinated behaviors between partners performing different parental tasks was very high during the entire nesting cycle. Analysis of the frequency of uncoordinated behaviors revealed females were more prone than males to skip turns only during the onset of nest building and the beginning of the nestling period. The highly similar and coordinated effort is probably essential to build their remarkable nest and reach the high nesting success that characterizes the species.