1 New Record of Allopreening Between Black Vultures (Coragyps atratus) and Crested Caracara (Caracara plancus) by Henrique Nazareth Souto1,3, Alexandre Gabriel Franchin1 & Oswaldo Marçal Júnior2

Need abstract and key words. Introduction Allogrooming is a social behavior in which members of certain species perform the cleaning of another individual belonging to the same group. It is a phenomenon often noted in many animal groups such as primates (Barret et al. 1999) and rodents (Stopka & Mcdonald 1999). For birds, the equiva- lent behavior is called allopreening and in contrast to mammals it has few reports in the scientific literature. It is generally performed by colonial birds and mixed flock species, apparently because individuals are forced to live very close to each other. On the other hand, solitary birds may also carry out this type of behavior, as recorded for Molothrus ater (Passeriformes: Icteridae), a nest parasite bird (Selander & La Rue 1961; Scott & Scott Grustrup-1983). Amongst vultures (Cathartidae), allopreening was recorded for turkey vul- tures (Cathartes aura) and Californian condors (Gymnogyps californianus) (Harisson 1965) in captivity. In nature, it apparently was first noticed in Black Vultures (Coragyps atratus) in Suriname (Haverschimidt 1976). Allogrooming/allopreening behavior including individuals of the same spe- cies is perfectly understandable. More difficult to interpret is the occurrence of this behavior when different species are involved. Interspecific allopreening between black vultures and crested caracaras (Caracara plancus) was reported by David and Jasperson (1984). In the present work we describe new records of allopreening involving these species in the Brazilian savanna.

1Postgraduate Program in Ecology and Conservation of Natural Resources, Federal University of Uberlândia 2Biology Institute, Federal University of Uberlândia, Umuarama Campus, Ceara street, Post office box 593, Mail code 38.400-902, municipality of Uberlândia, State of Minas Gerais, Brazil. 3Author for correspondence: [email protected]

Tirle: We need the order and and family of the 2 bird species. 2 Sociobiology Vol. 53, No. 1, 2009 Methods This study was conducted in the municipality of Uberlândia, State of Minas Gerais, Brazil, (48°18'39'W, 18°55'23'S). This area is inserted in the domain of the Cerrado (Brazilian savanna) and the natural vegetation is re- stricted to fragments due to intensive agricultural activities and reforestation (Araújo et al. 1997). The field work was performed fromD ecember 2006 to October 2007. We searched three sites located in the periphery of the city. The observations were performed from 9:00 A.M. to 6:00 P.M. according to animal focal methods with ad libitum sampling. All areas were sampled monthly, for 90 total hours of observation. Observations We recorded seven allopreening events between black vultures (Coragyps atratus Bechstein) and crested caracaras (Caracara plancus Miller). The

Fig. 1 - Interspecific allopreening between a crested caracara and a black vulture in an urban environment of Uberlândia, Minas Gerais, Brazil. (Photo: Henrique Nazareth Souto). Souto, H.Z. et al. — Allogrooming Between Black Vultures and Crested Caracara 3 average duration of such behavior was highly variable (9.38 ± 22.77 minutes). In all events, the behavior seems to have the same pattern: both species are very close to each other, remain for a considerable time in this position, al- ternating between monitoring the area and cleaning up feathers. After some time the birds move closer together and touch each other. On two occasions the crested caracara was seen slightly lowering his head, possibly showing submission in relation to the black vulture. After that, a bird touches the chest, neck or head of the other, which responds by conducting mutually the same behavior. After some time, the birds stop executing the behavior or they simply leave the perch (Fig. 1). Discussion and conclusion The more accepted hypotheses to explain this allopreening behavior are its importance in parasite removal (Freeland 1976) and its value in intra-social interactions (Call et al. 2002; Radford 2006). In a recent study developed with the green wood hoopoe, Phoeniculus purpureus, (Upiformes: Phoenicularidae), allopreening was interpreted as a mechanism to remove ectoparasites, since the studied species uses tree cavities for egg laying, and the proximity among the community’s members would favor the proliferation of such parasites (Radford 2006). Three assumptions, not mutually exclusive, are here considered to explain the interspecific allopreening between black vultures and crested caracaras: (1) Increased surveillance in mixed flocks. The group size effect and the many-eyes hypothesis. This hypothesis predicts that the larger size of the flock will increase the amount of guards within that group, so the group gains an increase in surveillance ability (Lima 1990). (2) Morph-behavioral limitations Vultures seem not to possess the capability to vocalize due to the absence of the syrinx (Sick 1997). Therefore, a possible reason for black vulture groups to tolerate the crested caracara's presence within their social group could be the fact that the caracaras have the ability to vocalize alarm cries, thereby also increasing vigilance against possible predators. (3) Opportunism by crested caracaras Cathartidae is one of the few bird families in which the representatives use 4 Sociobiology Vol. 53, No. 1, 2009 chemical odors find food location, as they use their strong sense of smell to find carrion kilometers away (Owre & Northington 1961; Houston 1986; McShea et al. 2000). Therefore, vultures are, at least in theory, much more efficient at carrion location than opportunistic species which have no records of such ability, such as the crested caracara. In that sense, the caracaras gain advantages in food detection by grouping up with black vultures. We conclude that allopreening between black vultures and crested caracaras is not an isolated behavior, and perhaps it happens widely among the distri- bution areas of both species throughout the world. Considering the possible synergy of the presented assumptions and our own observations, we believe that the allopreening would reinforce the social association between black vultures and crested caracaras. References Araújo, G. M., J.J. Nunes, A.G. Rosa, & E.J. Resende 1997. Estrutura comunitária de vinte áreas de cerrado residuais no município de Uberlândia, MG. Daphne 7 (2): 7-14. Barrett, L., S.P. Henzi, T. Weingrill, J.E. Lycett & R.A. Hill 1999. Market forces predict grooming reciprocity in female baboons. 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An experiment on the ability of free-ranging turkey vultures (Cathartes aura) to locate carrion by chemical cues. Chemoecology 10: 49-50. Owre, O.T. & P.O. Nothington 1961. Indication of the Sense of Smell in the Turkey Vulture, Cathartes aura (Linnaeus), from Feeding tests. American Midland Naturalist. 66: 200-205. Radford, A.N. & M.A. Du Plessis 2006. Dual function of allopreening in the cooperatively breeding green woodhoopoe, Phoeniculus purpureus. Behav. Ecol. Sociobiol. 61: 221-

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