Habitat use and space preferences of Eurasian Bullfinches (Pyrrhula pyrrhula) in northwestern Iberia throughout the year

Abstract

Background: For all vertebrates in general, a concerted effort to move beyond single season research is vital to improve our understanding of species ecology. Knowledge of habitat use and selection by Eurasian Bullfinches (Pyrrhula pyrrhula) is limited with regard to the non-breeding season. To date, research on the habitat of the Iberian subspecies iberiae consists of very general descriptions. In relation to space use, only broad features are available for the entire distribution range of Eurasian Bullfinches, including Iberia. Methods: In this study, seasonal preferences regarding habitat and space in a population of Eurasian Bullfinches are examined for the first time in the Iberian Peninsula, through direct observation during a six-year period. The essential habitat components, substrate selection and perch height were assessed. Results: Hedgerows were the key essential habitat component for bullfinches during all seasons. Nevertheless, small poplar plantations became increasingly important from winter to summer-autumn. Bullfinches perched mostly in shrubs/trees throughout the year, but there were significant seasonal changes in substrate use, ground and herbs being of considerable importance during spring-summer. Throughout the year, over half of the records corresponded to feeding, reaching almost 90% in winter. Generally, bullfinches perched noticeably lower while feeding. Male bullfinches perched markedly higher than females, notably singing males in spring-summer. Juveniles perched at a height not much lower than that of males. In all seasons, males tended to feed at greater heights than females. Bullfinches of different ages and sexes were seen bathing in all seasons except winter. Conclusions: Hedgerow habitat in general appeared to be valuable for bullfinches throughout the year. In summer and autumn, they selected sites with an abundance of food and shade, as well as shelter, a much-needed requirement for fledglings and moulting individuals. There was usually a close link between the most used and most consumed plant species in each season. Males appeared to assume a more important role in vigilance, and often they accompanied dependent young in June and July. Bullfinch conservation strategies should consider seasonal demand for habitat and space.