coparenting Canada geese?

[terry lowrey]

Several times in the last couple of weeks we've had three adult Canada geese on our nest platform. Normally the gander is very aggressive about chasing off other geese, but this intruder seems to be acceptable, even helping with tidying up the down lining. We're guessing it's a female since she's smallish. Today she stayed for quite some time.

The goslings should be hatching any day now.

But who is this third goose in the nest?

Ursula