Quote:
Originally Posted by Bramble  Wait until the third bird pitches up...  |
It's quite possible that there already
is a third bird! Here is part of a description about their behaviour, from my BirdGuides CDrom:
The dunnock has a remarkably varied and flexible mating system. Sometimes a territory supports just two birds, male and female which co-operate in rearing the young. However, a male with a good quality territory will sometimes attract and mate with two or even three females. More typically though, it is the female who tries to mate with more than one male since any male she has mated with then helps in the feeding of the young.