Birds using tram tracks in Poznari (Poland): Species, infrastructure use and behaviour

摘要

Transport infrastructures, mainly roads and railways, influence many aspects of bird life. The use of trams in urban areas for mass transit has been suggested as having a lower impact on the environment. However, to date, the impact of tram tracks and the surrounding infrastructure on birds has not been directly tested. Therefore, we posed two questions during a study of tramways in Poznan (western Poland): (1) which bird species use tram tracks and their infrastructure; and (2) how does their behaviour respond to moving trams. Tram tracks were recorded as used by 11 species, with four corvids (jackdaw Corvus monedula, rook Corvus frugilegus, magpie Pica pica and hooded crow Corvus cornix) totalling 66% of records and feral pigeon Columba livia contributing a further 24%. Species showed different usage patterns of the tram infrastructure. In the case of rook during winter, significantly more birds were observed further from a tram stop. In summer, a higher density of jackdaws occurred where track surroundings were vegetated, and both hooded crows in winter and magpies in winter were more abundant where track geometry was more complex. During our field work only two dead birds on tram tracks were observed. The results of this study, and a literature survey of other transport options, suggest that tram tracks are not very dangerous for birds, and at least from this point of view, can be recommended as an environmentally friendly transport system in urban areas.