It has also been observed that a pair living in an area does not sing, mate or build a nest even during the breeding season it means they do not possess any territory. In the case of rufouscollard sparrows of North America intruders, having no territory of their own, sneak into somebody else s territory and remain as inconspicuous as possible, awaiting some fatality to overtake one if not both of the resident birds. If it does, the lurkers take over their territory and become its masters. According to animal psychology, any animal already established in territory has an edge over the one coming from outside. It has been observed that lurkers usually get of the territory.
Some birds adopt different strategies to gain living space.
They lie low in another bird s territory and try to breed. It has been observed that homeless pairs of European tits sometimes wait for a resident pair to go through the territorial rituals, which include fighting off other birds, singing to announce possession, building the nest, patrolling the boundaries etc. After all this exercise the resident bird becomes less aggressive and starts devoting its time to incubating. This is the time when deprived birds sneak into the territory. They do not waste time, finding a suitable and safe place they build their nest and start laying and incubating.