| The hatchlings have a beak with a raptorial hook that they use to stab host nestlings. |
| After hatching, the altricial nestlings are brooded for 1 to 2 weeks depending on the weather. |
| The researchers say that nestlings in at least half of the nests they studied were eaten, mainly by martens and weasels. |
| All nestlings were banded, which enabled a study of recruitment to the breeding population. |
| Other studies even showed that nestlings fed by people were less afraid of new things until age 6 months than were birds reared by their parents. |
| The number of food deliveries made to supplemented and control nestlings were counted from the observation blind. |
