Blackcap (Sylvia atricapilla) Science Article 6
Nest predation is a major factor limiting the reproductive output of small passerines (Ricklefs 1969). Thus, selecting safe nest-sites is critically important for these birds. Nest concealment can inhibit transmission of visual, chemical or auditory cues to predators (Martin 1993). However, although there are numerous studies demonstrating the positive effects of concealment on nest survival (reviewed in Martin 1992), other studies were unable to find such an effect (e.g. Willson & Gende 2000).
VLADIMIR REMES, Ibis 147 (1), 213-216.