If one parent of an eyass is lost, who assumes parental duties?

In the context of bird behavior and specifically regarding eyasses, which are nestling hawks or falcons, the remaining parent assumes parental duties if one parent is lost. This is primarily due to the strong pair bonding and cooperative breeding behaviors exhibited by many raptor species. The remaining parent is typically well-equipped to continue caring for the young, as it has been actively involved in the parenting process and has developed a bond with the offspring.

The other options do not reflect the natural behaviors observed in these species. For instance, the other eyass would still be dependent on adult care and would not be capable of taking on parental duties themselves. The closest relative is also unlikely to intervene, as raptors typically do not rely on other relatives for assistance in raising their young. Lastly, if none of the adults engage in caring for the eyass, it would likely not survive, as they are completely dependent on adults for food, protection, and development during their early stages of life. Therefore, the role of the remaining parent is critical in ensuring the survival of the young if one parent is lost.