Combination of 1 or 2 coloured aluminium rings and metal ring (on other leg).
note 1 : the birds are identified with a combination of coloured aluminium rings. In addition, there are a few pairs of wild birds currently nesting near our aviaries that will probably join our colony after it release and therefore we would like to extend our colour ring scheme to wild birds that will be captured in the area around.
note 2 : coloured aluminium rings and metal ring in different legs. The coloured aluminium rings have the inscription “WV RADOLFZELL” and usedd colours are : blue, black, green, orange, purple, red and silver.
The colour rings used are manufactured and commercialized by Vogelringe : http://vogelringe.de
note 3 : The mechanisms of social navigation in Western Jackdaws.
The movement of wild animals has become a matter of high public relevance, not only for wildlife conservation, but also because it can impact economically relevant areas such as agriculture or contribute for disease transmission.
Sociality is a key aspect of animal movement. In fact, many species are known to move in social groups, including most of migratory species. However the mechanisms of social navigation are still little known. Theoretical predictions on how animal groups reach consensus may apply to moving animals. For instance, moving decisions of animal groups may be driven by one or a small number of leaders or be the result of a balanced consensus involving all individuals. However, the empirical evidence on this subject is scarce and necessary for testing specific predictions.
Although the movement of animals have been studied for a long time, the absence of adequate tracking techniques prevented researchers of deeply investigate the mechanisms of social navigation. In fact, most of the scientific knowledge on animal movement have been produced from mark and recapture studies, which provide very little detail on social interactions of moving animals. This scenario has recently changed thanks to the development of small GPS devices that can be directly attached to animals and monitor their movement. GPS tracking not only allows describing individual movement in great detail, but can also be used for studying social moving interactions, if a considerable number of individuals in a group are tracked.
To our best knowledge the first studies on social navigation using tracking techniques were only recently conducted using homing pigeons as model species. It was found that pigeons exhibit follower-leader relationships among individuals flying in flock formation, resulting in a flight hierarchical organization.
Here we propose to investigate the patterns of social organization in moving birds using the Western Jackdaw (Coloeus monedula) as model species. If a hierarchical organization applies to our model species we further propose to investigate the biological correlates of leadership.
A captive group of jackdaws has been established since 2008. The birds were collected as nestlings or young fledglings in the region of Nordrhein-Westfalen and brought to captivity in the Max-Planck-Institut für Ornithologie, Radolfzell. As a research protocol we propose to release the captive jackdaws after equipped with small GPS devices allowing for individual tracking in the long-term. The released birds are expected to settle as a free-ranging colony nearby the aviaries where were hold. For that purpose supplementary food and nesting conditions will be provided next to the aviaries. Semi-natural colonies of jackdaws have been already established using this procedure.
The GPS loggers will obtain and store the positional information for each individual, which will be automatically downloaded to a ground station located in the colony on a daily basis. The tracking information will be compared among individuals for follower-leader relationships, which will allow to investigate the existence of a flight hierarchy. If a hierarchical flight organization exists, leadership will be then correlated to a set of biological variables, including, sex, age, kinship, boldness, dominance, and some physiological parameters (baseline levels of testosterone and corticosterone).
