Brood Division and Parental Care in the Period Between Fledging and Independence in the Dunnock (Prunella Modularis)

Abstract

Abstract1. Brood division was observed in 12 out of the 21 broods of dunnocks. It was stable over the whole period of fledging to independence. 2. Undivided broods were significantly more likely to occur earlier in the season than divided broods. 3. Brood size had no significant effect on the age at which chicks reached independence. 4. The weight (on day 6) of chicks in undivided broods influenced the age at which they reached independence, but no significant relationship was found in divided broods. 5. The provision of extra food significantly reduced the age at which fledglings reached independence, indicating that territory quality may affect the timing of independence. The effects of extra food on brood division were unclear. 6. There was no differential splitting of the brood between the dominant male and the female in polyandry and polygynandry or between a monogamous male and his female. Males and females fed the chicks at similar rates. 7. Beta males who had helped to feed the nestlings were more likely to continue to help feed fledglings in larger broods. 8. There was a tendency for male parents to care for male offspring and female parents to care for female offspring.