Dear colleagues, We are preparing a database for a meta-analysis of the effect of geolocators on migratory songbirds and near-passerines. I am writing you to kindly ask for some basic information regarding your geolocator projects. We are aware that a couple of meta-analytical studies have already appeared, but the number of published geolocator studies has been increasing and, more importantly, we would like to include -if possible- also unpublished data. We feel that a not negligible part of the studies that have employed geolocators may have remained unpublished, especially in cases when no geolocators have been retrieved. In addition, some negative effects of geolocators may go unpublished for different reasons. At the same time, we think that it is important to investigate the impact of geolocators on birds.
Our aims are to calculate an overall effect of light-level geolocators on passerine birds where the main predictors would be sex, treatment (tagged vs. control) and structure of the geolocator. We would greatly appreciate any unpublished data on the return rates of geolocator-tagged and control birds. We can offer you co-authorship if you are interested to contribute with a sufficient amount of such data. In case you are willing to share your data, please, contact my student Vojtěch Brlík (email@example.com). Thank you very much for any help you can provide. Kind regards, Petr Procházka Institute of Vertebrate Biology, Czech Academy of Sciences