ECOLOGICAL CORRELATES OF HUMAN DISPERSAL IN 19TH-CENTURY SWEDEN

Historic Swedish human demographic data were used to examine ecological correlates of natal dispersal. In addition to sex and age of dispersers, these data contain information on social, spatial and temporal atributes influencing dispersal; information important to delimiting functional advantages of this behaviour. It was predicted that in the monogamous and, apparently, resource defence mating system of 19th century Sweden male competition for resources would result in (1) a female bias in dispersal and that (2) male dispersal would be influenced by the (a) relative local availability of resources and (b) individual ability to gain access to resources. Dispersal hazard, the probability that an individual will disperse over a given time period, rose sharply at the age of reproductive maturity, supporting the concept that dispersal is related to reproductive strategies. Females, throughout life, consistently had a higher probability of leaving their natal parish than did males. Parish resource availability and individual ability to access resources (Birth order and father's socio-economic class) correlated with natal dispersal probability of males. Dispersers, male and female, were predominantly pre-reproductive and may have contributed to inbreeding avoidance. Female dispersal also varied with availability of and individual access to resources, perhaps in response to availability of mates or due to pressures from other residents. © 1992 The Association for the Study of Animal Behaviour.