Birds with multiple homes. The annual cycle of the pallid swift (Apus pallidus brehmorum).

We tracked pallid swifts (Apus pallidus brehmorum) from a single breeding colony in Gibraltar over two years. Our results show movement of birds between specific regions within the non-breeding geographical area at specific times of the year. The tracking of a single individual showed remarkable fidelity to the areas visited between years. Furthermore, two pallid swifts tracked over the entire eight-month non-breeding period, while in Africa, gave no indication of coming to land, supporting previous findings of an airborne existence in swifts outside the breeding season. In addition, the crossing of the Sahara Desert to and from breeding grounds is remarkably fast, with one individual crossing it in just over a day. We discuss our findings in the context of bird migration evolutionary strategies.

Crag Martin neontology complements taphonomy at the Gorham's Cave Complex.

Species present in the fossil record may continue to exist at an archaeological site, allowing study that fine-tunes our picture of the ecological past. A large wintering population of Eurasian Crag Martins Ptyonoprogne rupestris (ECM) roosts at the 'Gorham's Cave Complex' UNESCO World Heritage site in Gibraltar, which is best known for its occupation by Neanderthals at times when ECMs were also present. Its complex geomorphology allows the study of use of different micro-sites (caves) within the roost. We used mark-recapture to test whether birds showed fidelity to micro-sites for roosting, and for differences in condition of birds across micro-sites. ECM showed very high fidelity towards micro-sites, within and between years, with > 90% chance of recapture at caves where they were first caught. Condition of birds differed between micro-sites, suggesting differences in roost quality between caves; birds were more likely to be recaptured at the micro-site where birds were in best condition, indicating higher survivorship. Our results demonstrate extremely fine-scale fidelity at the largest roosting site documented for ECM globally. Implications for conservation are discussed. The study provides current knowledge of a bird that has been using these caves since the Pleistocene and more generally on these caves as refuges.

Species-Specific Cuticular Hydrocarbon Stability within European Myrmica Ants.

Recognition is a fundamental process on which all subsequent behaviors are based at every organizational level, from the gene up to the super-organism. At the whole organism level, visual recognition is the best understood. However, chemical communication is far more widespread than visual communication, but despite its importance is much less understood. Ants provide an excellent model system for chemical ecology studies as it is well established that compounds known as cuticular hydrocarbons (CHCs) are used as recognition cues in ants. Therefore, stable species-specific odors should exist, irrespective of geographic locality. We tested this hypothesis by comparing the CHC profiles of workers of twelve species of Myrmica ants from four countries across Europe, from Iberia to the Balkans and from the Mediterranean to Fennoscandia. CHCs remained qualitatively stable within each species, right down to the isomer level. Despite the morphological similarity that occurs within the genus Myrmica, their CHCs were highly diverse but remarkably species-specific and stable across wide geographical areas. This indicates a genetic mechanism under strong selection that produces these species-specific chemical profiles, despite each species encountering different environmental conditions across its range.