Ecologists have found that Mediterranean gulls have adapted to the built environment and prefer it natural. This conclusion is allowed to make prolonged surveillance using GPS collars. Observations explain the increase in populations of gulls in the last decade. Article published in the journal Ecology and Evolution.
Despite the fact that economic activities of people reduces the natural habitat of wild animals, many species of animals adapt to human presence. Some of them become Sinanthropus: those for whom human environment is basic for life. Peking man are obligate parasites totally dependent on people and settlements outside of its almost not living like rock pigeon or house mouse.
If the animal is not strongly attached to a human dwelling, but simply uses it as a convenient food source, it is called optional Sinanthropus. So live, for example, common vole, common both in the fields and wild meadows. Since over time human activities intensifitsiruetsa, it is logical to assume that it can attract new types. In particular, recently released a study that shows that living in Britain seagulls are not only actively steal food, but also prefer the one which touched people.
Francisco Ramirez (Francisco Ramírez) from the University of Barcelona and his colleagues decided to find out how economic activity affects food habits of Mediterranean gulls (Larus michahellis), whose population has grown in the last decade. The study was conducted on the southern Atlantic coast of Spain, densely populated area with intensive sea, in particular fishing activities, where potentially a lot of food for the birds.
Because the gulls are very mobile and follow them like the colony of mice is impossible, the researchers decided to observe them during the year with the help of GPS navigation. To do this, they are caught in a network of 30 adults and attached to each tracker solar, weighing in at twenty grams, and do not hinder flight. Device every five minutes recorded the position, velocity and acceleration, and transmit data to a ground station when a Seagull flew close to her.
Data for a full year managed to get all six birds. Of the thirty original two bite of the clasp on the tracker, some were eaten by the predators, and the others likely ceased to fly close to the ground station. For the analysis of collected data, the researchers put the card of stay of birds at the map of human activity obtained from the analysis of night satellite imagery: the more light the more people. With the card removed, marking of birds in flight, because the researchers were interested in is collecting food.
In the result there was a significant correlation between nighttime lighting and the number of gulls in the area.