Past decades witnessed a strong decline of many songbirds that forage on or near the ground
in the Netherlands. Little is known about its direct causation but foraging conditions have
notably deteriorated. Ground-foraging songbirds prefer to forage on short vegetation as
it allows better accessibility to the ground. Nitrophilic grasses have expanded during the
last decades and now cover large expanses of former nutrient poor habitats. Tis has been
a result of acidifcation, N deposition and, until recently, strongly declined grazing by
Rabbit (Oryctolagus caniculus). Terefore, the amount of suitable short-grown habitat has
declined. And yet, localities exist where some of these songbirds still occur or, interestingly,
do not occur in spite of apparent suitable conditions for ground-foraging birds. One of
these species is the Northern Wheatear (Oenanthe oenanthe), the main character of this
thesis.

Van Oosten, H.H. (2015). On the brink of extinction : Biology and conservation of Northern Wheatears in the Netherlands. Proefschrift Radboud Universiteit Nijmegen.