Territoriality and song as flexible paternity guards in dunnocks and alpine accentors

I compare paternity defense strategies in the variable mating systems of alpine accentors Prunella collaris and dunnocks P. modularis. I show that in dunnocks breeding territoriality functions exclusively for mate defense. Male investment in territoriality increases with the number of females they are defending, and when females are removed males sharply decrease dieir song output and eventually abandon their territories. Further, I show that paternity defense strategies vary in relation to group composition. In single-male groups there is greater investment in territorial defense and less investment in mate guarding during the female fertile period dian in multimale groups. I discuss the influence of the contrasting habitats of dunnocks and alpine accentors on their paternity defense strategies.