Linear and Stable Dominance Hierarchies in Cooperative Carrion Crows

Cooperatively breeding birds typically form cohesive and stable groups that live year-round in all purpose territories where competition for resources is likely to arise. Understanding how group members negotiate over resources is crucial because conflicts may disrupt the stability of the group and may ultimately hinder cooperation. However, social relationships within the group have been largely neglected so far. Here we investigated how cooperatively breeding carrion crows (Corvus corone corone) share a food source, by observing dyadic interactions in 29 territories that contained retained offspring of the breeding pair and/or immigrants. We found that crows formed linear and stable dominance hierarchies, which were stronger for males than females. We suggest that this difference mirrors the level of competition for resources other than food, such as reproduction and territory inheritance, which is higher in males than females. Interestingly, immigrant males dominated male offspring, suggesting that, for the resident breeder, which is the alpha member of the group, the benefits of an association with an immigrant overcome the costs of having his sons pushed down in the hierarchy. Our study uncovered the key factors that determine hierarchical relationships among cooperatively breeding crows and highlighted the need of focussing on social interactions in every context of group living to fully explain the dynamic of cooperation at the nest.

[1]  N. Metcalfe,et al.  Familiarity Breeds Tolerance: the Development of Social Stability in Flocking Siskins (Carduelis spinus) , 2010 .

[2]  M. Graham,et al.  Stability of dominance relationships in crayfish depends on social context , 2009, Animal Behaviour.

[3]  J. Martin Marcos,et al.  Helpers but not breeders adjust provisioning effort to year-round territory resource availability in carrion crows , 2008, Animal Behaviour.

[4]  Shigeru Watanabe,et al.  Formation of linear dominance relationship in captive jungle crows (Corvus macrorhynchos): Implications for individual recognition , 2008, Behavioural Processes.

[5]  J. Martin Marcos,et al.  Reproductive success increases with group size in cooperative carrion crows, Corvus corone corone , 2008, Animal Behaviour.

[6]  J. Martin Marcos,et al.  Costs of chick provisioning in cooperatively breeding crows: an experimental study , 2007, Animal Behaviour.

[7]  S. Quader,et al.  Mother guarding: how offspring may influence the extra-pair behaviour of their parents , 2006, Proceedings of the Royal Society B: Biological Sciences.

[8]  J. Martin Marcos,et al.  Experimentally increased food resources in the natal territory promote offspring philopatry and helping in cooperatively breeding carrion crows , 2006, Proceedings of the Royal Society B: Biological Sciences.

[9]  Hilde Vervaecke,et al.  Measuring and testing the steepness of dominance hierarchies , 2006, Animal Behaviour.

[10]  Leif Engqvist,et al.  The mistreatment of covariate interaction terms in linear model analyses of behavioural and evolutionary ecology studies , 2005, Animal Behaviour.

[11]  Michael Griesser,et al.  Does year-round territoriality rather than habitat saturation explain delayed natal dispersal and cooperative breeding in the carrion crow? , 2005 .

[12]  J. Martin Marcos,et al.  Effect of parentage and relatedness on the individual contribution to cooperative chick care in carrion crows Corvus corone corone , 2005, Behavioral Ecology and Sociobiology.

[13]  J. Langbein,et al.  Analysing dominance relationships by sociometric methods—a plea for a more standardised and precise approach in farm animals , 2004 .

[14]  T. Clutton‐Brock,et al.  Breeding success in cooperative meerkats: effects of helper number and maternal state , 2003 .

[15]  J. Martin Marcos,et al.  Kin Selection in Cooperative Alliances of Carrion Crows , 2003, Science.

[16]  J. Martin Marcos,et al.  Direct fitness benefits of group living in a complex cooperative society of carrion crows, Corvus corone corone , 2002, Animal Behaviour.

[17]  J. Martin Marcos,et al.  COOPERATIVELY BREEDING GROUPS OF CARRION CROW(CORVUS CORONE CORONE) IN NORTHERN SPAIN , 2002 .

[18]  M. Cant,et al.  Helping effort and future fitness in cooperative animal societies , 2001, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[19]  B. Hatchwell,et al.  Ecological constraints, life history traits and the evolution of cooperative breeding , 2000, Animal Behaviour.

[20]  R. Elwood,et al.  Imperfect assessment and limited information preclude optimal strategies in male–male fights in the orb-weaving spider Metellina mengei , 2000, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[21]  L. Freeman,et al.  Finding an appropriate order for a hierarchy based on probabilistic dominance , 1999, Animal Behaviour.

[22]  Hanna Kokko,et al.  Social queuing in animal societies: a dynamic model of reproductive skew , 1999, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[23]  A. Cockburn.  EVOLUTION OF HELPING BEHAVIOR IN COOPERATIVELY BREEDING BIRDS , 1998 .

[24]  R. Griffiths,et al.  A DNA test to sex most birds , 1998, Molecular ecology.

[25]  I. Owens,et al.  Cooperative breeding in birds: a comparative test of the life history hypothesis , 1998, Proceedings of the Royal Society of London. Series B: Biological Sciences.

[26]  J. Poston.  Dominance, access to colonies, and queues for mating opportunities by male boat-tailed grackles , 1997, Behavioral Ecology and Sociobiology.

[27]  Han de Vries,et al.  An improved test of linearity in dominance hierarchies containing unknown or tied relationships , 1995, Animal Behaviour.

[28]  H. Richner.  Phenotypic correlates of dominance in carrion crows and their effects on access to food , 1989, Animal Behaviour.

[29]  W. Jackson,et al.  Linearity in dominance hierarchies: a second look at the individual attributes model , 1988, Animal Behaviour.

[30]  Jerram L. Brown,et al.  Social dominance in communal Mexican jays Aphelocoma ultramarina , 1986, Animal Behaviour.

[31]  L. Persson.  Asymmetrical Competition: Are Larger Animals Competitively Superior? , 1985, The American Naturalist.

[32]  Kathryn J. Schneider.  Dominance, predation, and optimal foraging in white-throated sparrow flocks , 1984 .

[33]  Michael C. Appleby,et al.  The probability of linearity in hierarchies , 1983, Animal Behaviour.

[34]  G. E. Woolfenden,et al.  Dominance in the Florida Scrub Jay , 1977 .

[35]  R. Johnstone,et al.  Ecology and Evolution of Cooperative Breeding in Birds: Reproductive skew , 2004 .

[36]  Craig A. Tovey,et al.  Two's Company, Three's a Crowd: Differences in Dominance Relationships in Isolated Versus Socially Embedded Pairs of Fish , 2003 .

[37]  Truman P. Young,et al.  Ecological models of female social relationships in primates: similarities, disparities, and some directions for future clarity , 2002 .

[38]  J. Ekman,et al.  DELAYED DISPERSAL: LIVING UNDER THE REIGN OF NEPOTISTIC PARENTS , 2001 .

[39]  W. Piper.  Social Dominance in Birds , 1997 .

[40]  C. Drews.  THE CONCEPT AND DEFINITION OF DOMINANCE IN ANIMAL BEHAVIOUR , 1993 .

[41]  A. Zahavi,et al.  Cooperative Breeding in Birds: Arabian Babblers: the quest for social status in a cooperative breeder , 1990 .

[42]  W. Koenig,et al.  Reproductive Sociality. (Book Reviews: Cooperative Breeding in Birds. Long-Term Studies of Ecology and Behavior.) , 1990 .

[43]  J. Lamprecht,et al.  Social-dominance and reproductive success in a goose flock (Anser-indicus) , 1986 .