What is the collective term used for the large groups of ducklings cared for communally by female eiders?

Answer

Crèches

After leaving the nest, ducklings join massive communal groups known as crèches, where one or more female guardians, sometimes called 'aunts,' watch over broods potentially numbering up to one hundred young.

What is the collective term used for the large groups of ducklings cared for communally by female eiders?
birdfeatherduckeider duck