Feral pigeons are descendants of wild rock pigeons that have adapted to the urban habitat. They have partially conserved the foraging behaviour of their wild ancestors (flights to agricultural areas) but have also developed new habits. Previous studies on the foraging strategies of feral pigeons have given various results, e.g. maximum distances reached by the pigeons (measured in a straight line from the resting places) differed between 0.3-0.5 km and 18-25 km. This study focuses on the spatiotemporal activity of feral pigeons in the urban habitat. We equipped 80 free-living feral pigeons from Basel, Switzerland with GPS receivers. We found three different foraging strategies for pigeons in Basel: (1) in the streets, squares and parks near the home loft, (2) in agricultural areas surrounding the city, (3) on docks and railway lines in harbours. The maximum distance reached by a pigeon was 5.29 km. More than 32% of the pigeons remained within 0.3 km of the home lofts and only 7.5% flew distances of more than 2 km. Females covered significantly longer distances than males, preferring to fly to more abundant and predictable food sources. Temporal activity patterns showed to be influenced by sex, breeding state and season. In contrast to wild rock pigeons and to feral pigeons in other cities, pigeons in Basel showed a clear bimodal activity pattern for breeding birds only. The differences between our results and those of other studies seem to be partly methoddependent, as the GPS-technique allows to record the pigeons' localisations continuously in contrast to other methods. Other differences might be due to different kinds of food supply in the various cities. Our study shows that feral pigeons have individual foraging strategies and are flexible enough to adapt to different urban environments.

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Feral Pigeons Columba livia live in almost every city in the world and are often a problem because of their large numbers. Knowledge of the spatial use of the city by Pigeons is important for population control management. Previous studies have given contradictory results concerning the urban area used by Pigeons and their feeding strategies. We used the global positioning system (GPS) to investigate the spatial use of urban habitats by Feral Pigeons in Basel, Switzerland. The total ranges of the subpopulations varied between 32.9 and 306.3 ha and overlapped partially. The total ranges of individual Feral Pigeons varied between 2.9 and 150.6 ha. Pigeons from a single loft had one or two main feeding places and up to 33 other places that they used for occasional feeding or for resting. Individual Pigeons visited up to ten different locations. Our study shows that Feral Pigeons have individual feeding strategies and are flexible enough to adapt to different urban environments. Therefore, we must contradict the view that Feral Pigeons are dependent on intentional feeding by humans and are unable to fly more than a few hundred metres. Our results are important for Pigeon control management, biomonitoring projects using Feral Pigeons as indicators of pollution and the study of disease transmission. Pigeon control management based on killing has only a local and temporary effect, because Pigeon subpopulations are interconnected. Pigeons from other areas will replace removed individuals. Biomonitoring projects usually assume that Pigeons show a limited mobility. Our study reveals that this is not a generally valid assumption. Because Pigeon subpopulations are connected, diseases can be spread over an entire urban area. This is of human concern, as seven infectious diseases have been shown to be transmitted from Feral Pigeons to humans.

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