Īn essential aspect when applying data loggers to seabirds is to ensure that the bird is not suffering from the procedure. given in Grémillet et al.(2004), Weimerskirch et al. (2002) ).Įxamples of comprehensive studies are e.g. Such a monitoring may focus at hydrographic structures but also at biological properties such as feeding hot-spots and productivity (overview e.g. It has been demonstrated that seabirds can thus passively collect a vast amount of data that may allow us to monitor the environment. More recent studies have also investigated how seabirds use their environment as more and more environmental parameters can be collected (e.g. where they forage, where they migrate, where they dive and how deep, how high they fly and at which speed (Fig. The application of data loggers to seabirds has mainly focussed on biological aspects of the birds, e.g. A brief overview of the history of this technology is given e.g.
These loggers have to be retrieved from the birds or from the sea to download the data to a computer. radio-telemetry and satellite telemetry) in so far as they do not transmit information permanently or at a given interval but store information. 1).ĭata loggers differ from other telemetry devices (e.g. The miniaturization process in electronic technology effectively helped to reduce the size of such devices so that more and more species can now be worked with and more and more parameters can be measured (Fig. In the beginning, devices have been very large so that they could hardly be fitted to the largest seabirds, mainly penguins.
Future research should focus on the costs and benefits of altered daily rhythmicity in birds thriving in urban areas.Seabirds have been instrumented with telemetry devices mainly since the 1970s to learn more about seabirds and their marine environment.
Our results point at artificial light at night as a major driver of change in timing of daily activity. A strong seasonal effect was detected in both urban and rural populations, such as birds tended to be active earlier in the morning and later in the evening (relative to civil twilight) in the early breeding season than at later stages. Light exposure at night and onset/end of daily activity timing was not different between weekdays and weekends, but all noise variables were. Birds exposed to higher amounts of light in the late night showed earlier onset of activity in the morning, but light at night did not influence end of daily activity. Onset of daily activity was significantly advanced in both urban sites compared to the rural population, while end of daily activity did not vary either among sites. We then compared activity, light at night exposure and noise levels between weekdays and weekends. We first analysed the relationship between light at night, weather conditions and date with daily activity onset and end. We tagged these birds with light loggers and simultaneously recorded changes in activity status (active/non-active) through an automated telemetry system. We captured adult male European blackbirds (Turdus merula) in one rural forest and two urban sites differing in the degree of anthropogenic disturbance. Organisms have naturally evolved daily rhythms to adapt to the 24-h cycle of day and night, thus, it is important to investigate the potential shifts in daily cycles due to global anthropogenic processes such as urbanization. In birds, it has been hypothesized that artificial light at night can affect daily aspects of behaviour, but one caveat is the lack of knowledge about the light intensity that wild animals, such as birds, are exposed to during the night. The growing interest in the effects of light pollution on daily and seasonal cycles of animals has led to a boost of research in recent years.