Gentoo Penguins nests at edge of colony
Pygoscelis papua papua
These gentoo nests are spaced out in a way that nearly all penguin nests are spaced out, at just over two "peck lengths" apart. If a penguin sitting on its nest can get a peck at a nearby or passing penguin, then it will usually do so. The resulting spacing is that penguins sitting on adjacent nests are just that bit too far away to reach each other, so neither feels immediately threatened and peace ensues. It reminds me of House of Commons in the English Parliament where the government and opposition benches are situated just over two sword lengths apart, should the honourable gentlemen have decided to circumvent the electorate in the days when that sort of thing went on.
The down side of this arrangement is that when a penguin wants to leave the nest to go fishing, or if it's coming back from fishing, it becomes in range of both beaks from the adjacent nests when walking through the colony. So for the time from arrival at the colony in the spring to when the chicks have grown up a bit and hang around off the nest in "creches", coming and going can be quite painful for these hardy birds.
Photo copyright - Paul Ward / coolantarctica.com