[alanjns]

Hi Amanda,

I was stumped too when I first heard the term 'eclipse'. I got this of the RSPB website, hope it helps:

After breeding, ducks moult (replace the old, worn-out feathers with new ones). Ducks are peculiar in that they moult all their flight feathers at once. For about a month, they are flightless and very vulnerable to predators.

To provide some protection, particularly for the brightly-coloured males, the moult starts with their bright body feathers. These are replaced by dowdy brown ones, making them look much like females. This eclipse plumage is why in mid-summer, it seems that all the drakes have gone.

Once the flight feathers have regrown, the birds moult again, and by October the full colours have been regained and the various species of ducks are easily recognisable.

Cheers,

Alan