Chestnut Crowned Babbler Immigrants, breeding, Australia
In cooperatively breeding species, adults that are not the parents are often expected to assist in raising the young, for instance by feeding young. Across systems, there are many hypotheses as to how this seemingly non-adaptive behavior is derived. For many species, kin selection, which allows individuals related to the brood to gain indirect fitness benefits by helping is thought to drive cooperation. However, in those species, additional individuals may also immigrate into the group and what the rules are for their contributions to the young are still relatively unknown; for instance, is there a difference between male and female immigrants, possibly due to differences in future mating opportunities? This research analyzes that in a cooperatively breeding species endemic to Australia, the chestnut crowned0babbler (Pomatostomus ruficeps). Here, using provisioning as a metric of helping, we determine the relationship between helping and the sex of immigrant individuals. To assess provisioning, passive integrating transponder (PIT) tags were inserted into adults to track nest visits, which are associated with chick provisioning in this species. Further, as chestnut crowned babblers are sexually monomorphic, all immigrants were sexed molecularly. Preliminary analysis indicates that there is no difference in provisioning between male and female immigrants, however, more work needs to be done to compare immigrants generally to related helpers. This may indicate helping does not play as significant a role in future breeding opportunities for immigrants, highlighting it may not be a “rule” of cooperative behavior in this species.
Ahrenholtz, Michaela, "Helping Behaviors Among Chestnut Crowned Babbler Immigrants" (2021). IdeaFest. 280.