the latter alone, though they do occasionally catch and eat nestlings and even adults. In addition, falcons are obligate users of white-headed buffalo weaver nests; therefore, they experience all of the benefits these nests provide without the energetic cost of building or maintaining them. Weavers also do not maintain these nest chambers occupied by falcons, increasing the likelihood that these particular chambers will break off the main colony . However, falcons appear to have a preference for chambers away from the center of the colony and with shorter entrance tunnels. Although it is likely that falcons would benefit from selecting chambers with better insulation, they are larger than weavers and as a result may struggle to access chambers through longer entrance tunnel. Pygmy falcons mark their nests by the use of their faecal matter, but the reasons behind this is unknown. It has been suggested that this conspicuous faecal mat (white when fresh and turning pinkish with age) present at the entrance of the chamber could deter snakes and reduce the number of ectoparasites. Faecal matter is also though to boost the immune system of chicks as well as signal to conspecifics. Faecal mats at the entrance of occupied chambers may serve as a social signal to indicate to other falcons that a colony is occupied. On one occasion a male pygmy falcon was recorded killing another male, and then subsequently took over the dead males territory and reproduced with the dead males partner. Cooperative breeding Pygmy falcon territories are occasionally inhabited by groups, where there are more than two adults living together and tending nestlings. There are four potential reasons for this behaviour: defence, co-operative polyandry, delayed dispersal of offspring and cooperation, and thermoregulation (warmth). Corroboration for the last is that in winter African pygmy falcons nest further inside the nest of sociable weavers, where there is better insulation. Status Pygmy falcons are not threatened. References External links Pygmy Falcon - Species text in The Atlas of Southern African Birds. Birds Of Prey Monotypic bird genera pygmy falcon Birds of prey of Sub-Saharan Africa Birds of East Africa Birds of Southern Africa pygmy falcon pygmy falcon