Sparrows (Passer spp.) have long been presumed to rely on railway traffic during their long-distance terrestrial dispersion. The currently ongoing range expansions of the Spanish Sparrow (Passer hispaniolensis) and the Red-rumped Swallow (Hirundo daurica) in Central Europe provide an opportunity to develop this idea into a testable hypothesis. Both species are small, synanthropic passerines but the latter one is highly aerial and mobile. Therefore, Red-rumped Swallows are not supposed to rely on railways for spatial dispersion so that their distance from railway lines is supposed to reflect observers’ distribution, but not otherwise influenced by railway proximity. I have analyzed published data from Hungary and North Serbia (Vojvodina, except for its South Banat District) from 2000 onward. During this period, both species exhibited a slow northward range expansion on the Southern edge of the study area but have not yet established self-sustaining populations. Vagrant individuals of the Spanish Sparrow and its hybrid Italian Sparrow (Passer italiae) occurred significantly closer (N = 8, range = 0.01–3.36 km) to railway lines than vagrant Red-rumped Swallows (N = 23, range = 0.45–13.76 km). This constitutes an empirical evidence supporting the idea that sparrows tend to rely on railway traffic for long-distance dispersion.
- Freight trains
- Human facilitated dispersal
- Synanthropic birds
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics