Measuring nestlings

When the nestlings are close to taking their first flight at 55 days of age, the ornithologists measure them for the last time. They pay particular attention to the plumage that is very similar to the one of their parents.

Deux chouettes d’une même couvée. Les différences de couleurs sont importantes.
Jeunes chouettes effraies

Two barn owl siblings strongly differ in colouration!

The breeding season is over when the ornithologists measure the last chicks of the second annual broods at the end of October/beginning of November.