The Siberian jay project was initiated by Prof. Jan Ekman (Uppsala University) in 1988 to understand the evolution of family living in birds. Our study site is located in Arvidsjaur, Northern Sweden, 100km south of Arctic circle. Initially, Folke Lindgren, a local ornithologist, started small scale research on Siberian jays in 1953, and he continued doing so for over 65 years.
Siberian jays live in kin groups where offspring remain with the parents up to 5 years beyond independence, but these retained offspring do not engage in helping at the nest. Dominant brood members evict subordinate brood mates 4-8 weeks after independence from the natal territory. These individuals disperse, and join other groups, which results in variation in kinship between breeders and non-breeders. In the past, we have focused on understanding nest predation (main responsible: Sönke Eggers), population dynamics(main responsible: Magdalena Nystrand), life-history decisions (main responsible: Jan Ekman) and behaviours facilitating family living (main responsible: Michael Griesser). Parents use a large array of antipredator behaviours to boost the survival of their offspring. In particular, jays evolved a rich vocabulary which allows them to communicate predator category, risk and above all the behaviour of their main predator (i.e., hawks). By removing fathers from groups, we demonstrated that the presence of both parents is crucial for offspring to delay dispersal, since only the presence of both parents prevents unrelated dominants from joining the group and chasing offspring away. A consequence of all the parental nepotism, retained offspring have a much higher first winter survival than immigrants.
Using data collected by Folke Lindgren, we could show the influence of forestry on long-term territory occupancy and breeding success. For Siberian jays, it seems critical to have enough large patches of unthinned forest in their territory to breeding successfully, and thus as well for long-term occupancy of territories.
Our research has been/is financed by: the Swedish Research Council, the Swedish Environment Protection Agency, Stiftelsen för Zoologisk forskning, C.F. Liljewalchs resetipendium, Stiftelsen Alvins fond för fågelskydd, Hiertas Minnesfonds, Kungl. Skogs- och Lantbruksakademien, the Swiss National Science Foundation.