Annual variation in habitat use by Northern Lapwings Vanellus vanellus and Eurasian Golden Plovers Pluvialis apricaria wintering in Portugal
115 – 127
1 September 15
Domingos Leitão, Salvador Peris
Departamento de Biología Animal, Facultad de Biología, Universidad de Salamanca, E-37071, Salamanca, Spain
This study compares farmland habitat use by Northern Lapwings Vanellus vanellus and Eurasian Golden Plovers Pluvialis apricaria. The number and activity of lapwings and golden plovers per field unit was recorded in four study areas with different farming systems in S Portugal and during three consecutive winters (1997–2000) with different rainfall conditions. Habitat use vs. availability was compared using Bailey’s Simultaneous Confidence Intervals. Compared to golden plovers, lapwings used a greater proportion of field units, and fed in all available habitat types, although they preferred pasture and stubble of spring-grown crops. In normal winters, the stubble of spring-grown crops was the most important feeding habitat in areas where it was available but only when located in productive soils. Lapwings showed the ability to exploit farming activities (such as ploughing) and other habitats outside the farming system (such as mudflats). Golden plovers preferred fields larger than 20 ha and avoided fields smaller than 10 ha. Golden plovers preferred to feed in pastures in all three winters and, unlike lapwings, tended not to use stubble and recently ploughed fields. Rainfall is discussed as the likely driver of the observed variation among winters. Both species, and especially lapwings, used a greater proportion of field units in dry winters than in wet ones. Lapwings might be better suited to survive dry winters, as they fed in a broader range of habitats than golden plovers, which were more dependent on pastures and might face considerable difficulties under dry conditions.