Population and Breeding Biology of Marsh Harriers in Britain Since 1900

Breeding biology of Montagu's HarrierCircus pygargusL. in agricultural environments of southwest Spain; comparison with other populations in the western Palearctic

“…Contrary to Lack's hypothesis, the most successful clutch size in the study area was not equal to the modal one but larger, 42 as is typical in the genus Circus. 23,31,46,47 No seasonal decline in clutch size was registered, as reported by Schipper. 25 Seasonal variation has however been reported for other harriers, 23,25,31,47 and there is similar evidence among birds of prey and owls, 32,35 as well as for most single-brooded species of birds.…”

Criteria voor de beoordeling van de lokale staat van instandhouding van de Vogelrichtlijnsoorten in Vlaanderen: Versie 2.0

“…geeft per broedpaar een oppervlakte van 12,5 tot 25 ha aan voor een nestplaats in moerassige vegetatie in Engeland. Underhill-Day (1984) vermeldt een gemiddelde oppervlakte van 20 ha. In het oosten van Polen wordt de oppervlakte van de nestplaats geschat op 14 à 20 ha (Buczek & Keller 1994).…”

Range Expansion of Raptors in Britain and the Netherlands Since the 1960s: Testing an Individual-Based Diffusion Model

“…In the Netherlands, numbers of sparrowhawk, Accipiter nisus, and goshawk, A. gentilis, decreased enormously (Thissen, Muiskens & Opdam 1981;Opdam, Burgers & Miiskens 1987), and, to a lesser extent, also those of the buzzard, Buteo buteo (Bijlsma 1994). In Britain the hazardous effects of organochlorines were first noticed and proved in the peregrine, Falco peregrinus (Ratcliffe 1970), and a few years later in the sparrowhawk (Newton & Bogan 1974), the buzzard and the marsh harrier, Circus aeruginosus (Tubbs 1976;Underhill-Day 1984). In Britain use of these chemical compounds was reduced from 1962, and banned altogether in 1986.…”