Flexibility of habitat use in novel environments: insights from a translocation experiment with lesser black-backed gulls.

Being faced with unknown environments is a concomitant challenge of species' range expansions. Strategies to cope with this challenge include the adaptation to local conditions and a flexibility in resource exploitation. The gulls of the group form a system in which ecological flexibility might have enabled them to expand their range considerably, and to colonize urban environments.

True navigation in migrating gulls requires intact olfactory nerves.

During migratory journeys, birds may become displaced from their normal migratory route. Experimental evidence has shown that adult birds can correct for such displacements and return to their goal. However, the nature of the cues used by migratory birds to perform long distance navigation is still debated.