Study system
Data on toe damage were collected during three breeding seasons (2021-2023) as part of a long-term (2009-present) study of red-necked nightjars in the Doñana National Park, S Spain (see Camacho et al., 2014, 2022 for details on the study site and sampling protocols). Most nightjars arrive in the study area in early May and generally postpone their migration departure until mid October (i.e. approx. 5½-month stay in the breeding area; Camacho, 2013a). GPS tracks of adult nightjars from the study population indicate that most individuals migrate through Morocco and Mauritania to spend the non-breeding season (November-April, approx. 5½ months) in S Mali and SE Guinea (authors’ unpubl. data).
Nightjars spend much of their time on the ground: they are ground-nesting birds and both members of the pair share incubation and chick-rearing duties for over 35 days, the female taking the larger share (Camacho, 2013a). During the day, they remain motionless on the ground in the shade of trees or shrubs (Camacho et al., 2014). During the night, they use open spaces on the ground as perches to facilitate detection of aerial insects (mainly moths), although they can also occasionally pick up terrestrial insects that are running around (Jackson, 2003). In spending so much time on the ground, nightjars are exposed to accidental contact with all sorts of diurnal and nocturnal ground-dwelling creatures.