Allopreening between different bird species has rarely been reported in nature (Harrison 1969) but there are at least two published records regarding American Black Vultures (Coragyps atratus) preening both the Crested Caracara (Caracara cheriway) and the Southern Caracara (C. plancus), in Texas, USA (David & Jesperson 1984) and in Mato Grosso, Brazil (Souto et al. 2009) respectively. Here I report on a further observation made at Los Tarrales Reserve, near Atitlán volcano, Guatemala, on 1 November 2012. This observation confirms that the described behaviour is geographically widespread and it also appears to be the first time that it has been video-recorded.
In both our observation and that from Texas, the vulture was preening the caracara but not vice-versa. In the Brazilian reports it seems that the caracaras also performed some preening of the vultures after being preened by them. In all cases the vultures started preening after a “head-down” display by the caracaras that could be interpreted as an invitation (David & Jesperson 1984). Intraspecific allopreening is known for American Black Vultures (Haverschmidt 1977) but it seems to be rare among Falconidae (White et al. 1994) and unreported for caracaras (Polyborini).
As in all cases the allopreened body areas were those, such as the head and neck, that are inaccessible during autopreening, it seems probable that the main function of this behaviour could be parasite removal. However, other possible functions of allopreening have been suggested, such as reducing aggression (Harrison 1965, Forsman & Wight 1979) or reinforcing the well-known foraging and roosting association between caracaras and black vultures (David & Jesperson 1984), in which caracaras benefit from the vultures’ sense of smell to find food and the vultures benefit from the caracaras’ ability to vocalize loudly, alerting them of danger (Souto et al. 2009).
David, N.G. & Jasperson, B.D. (1984). Interspecific allopreening between crested caracara and black vultures. Condor 86(2): 214–215.
Forsman, E.D. & Wight, H.M. (1979). Allopreening in owls: what are its functions? Auk 96(3): 525–531.
Haverschmidt, F. (1977). Allopreening in the Black Vulture. Auk 94(2): 392.
Harrison, C.J.O. (1965). Allopreening as agonistic behaviour. Behaviour 24(3): 161–208.
Harrison, C.J.O. (1969). Further records of allopreening. Avicultural Magazine 75: 97–99.
Souto, H.N., Franchin, A.G. & Júnior, O.M. (2009). New record of allopreening between Black Vultures (Coragyps atratus) and Crested Caracara (Caracara plancus). Sociobiology 53(1): 1–5.
White, C.M., Olsen, P.D. & Kiff, L.F. (1994). Family Falconidae (Falcons and Caracaras). Pp. 216–247 in Del Hoyo, J., Elliott, A. & Sargatal, J. (1994), Handbook of the Birds of the World. Volume 2: New World Vultures to Guineafowl. Lynx Edicions, Barcelona.