COOPERATIVE BREEDING IN THE VULTURINE GUINEAFOWL (Acryllium vulturinum) AT MPALA RESEARCH CENTER, LAIKIPIA COUNTY KENYA

Abstract

Cooperative breeding is widely reported across the animal kingdom. In birds, it is thought to be more common in altricial species (where chicks are dependent in the nest after hatching), with few described cases in precocial species (where chicks move independently straight after hatching). The study examined cooperative breeding in a precocial species, the vulturine guineafowl (Acryllium vulturinum), at the Mpala Research Centre, Laikipia Kenya. The aim of the study was to investigate whether vulturine guineafowl breed cooperatively, and, if so, how help is distributed among group members. To achieve this, the study determined who breeds, quantified the investments by females during incubation, and observed who is closely associated to the chicks. The study determined whether non-breeders provide care at same levels to parents, and whether they pay any costs to helping. By following colour-banded females, the study found that multiple females can breed within each group, with each female attending to her own nest. Data from sixteen incubating females fitted with solar-powered high-resolution GPS tags revealed high female attendance, with females spending 97.6% of the incubation period on the nest. In one social group of vulturine guineafowl where all individuals were colour-banded, males were over-represented among the individuals that were detected with clutches more than expected by chance, and detailed observations found that these individuals exhibited cooperative breeding behaviour including caring for the chicks by covering them, calling them if they find a food resource and guarding them. In three focal clutches from this group, the study found no overlap among individuals that were significantly associated with each clutch, suggesting that helpers specialized on specific clutches. Focal follows of clutches found that helpers provide a substantial amount of care, and as a result none of the mothers provided the majority of the care to the chicks. Finally, helping was costly, focal follows showed that helpers expressed a significant reduction in time spent foraging while providing allo-parental care (P<0.01). In conclusion, vulturine guineafowl are cooperative breeders, and express cooperative breeding that is combined with an unusual plural- breeding social system. Future research on this system could focus on determining the factors that drive helpers to specialize on specific clutches, which could reveal important insights into the fine-scale drivers of cooperative breeding