Publication Type: | Journal Article |
Year of Publication: | 1997 |
Authors: | Corbacho, C, Sánchez, JM, Sánchez, A |
Journal: | Bird Study |
Volume: | 44 |
Date Published: | 1997 |
ISBN Number: | 0006-3657 |
Keywords: | Accipitridae, Circus, Circus pygargus, Spain |
Abstract: | We studied the breeding biology of Montagu's Harrier in an agricultural habitat at various breeding sites in Extremadura (southwest Spain). Clear latitudinal trends were observed on laying date and clutch size compared to other Western Palearctic populations: as laying starts earlier, clutch size declines in southern populations. Climate and feeding could be the main factors involved. In addition to natural factors, the species' use of cultivated areas as nesting habitat at Southern latitudes is the major determinant of breeding success. Artificial nest management at harvest time has been shown to be effective in reducing losses due to farming activities. Such conservation measures reduce the mortality rate of nestlings and consequently increase the reproductive success of breeding pairs. Nevertheless, endogenous factors related to individual breeding condition limit the effect of artificial nest management. Mediterranean populations of Montagu's Harrier seem to be highly dependent on conservation measures because of the high failure rates for breeding in the absence of such intervention.We studied the breeding biology of Montagu's Harrier in an agricultural habitat at various breeding sites in Extremadura (southwest Spain). Clear latitudinal trends were observed on laying date and clutch size compared to other Western Palearctic populations: as laying starts earlier, clutch size declines in southern populations. Climate and feeding could be the main factors involved. In addition to natural factors, the species' use of cultivated areas as nesting habitat at Southern latitudes is the major determinant of breeding success. Artificial nest management at harvest time has been shown to be effective in reducing losses due to farming activities. Such conservation measures reduce the mortality rate of nestlings and consequently increase the reproductive success of breeding pairs. Nevertheless, endogenous factors related to individual breeding condition limit the effect of artificial nest management. Mediterranean populations of Montagu's Harrier seem to be highly dependent on conservation measures because of the high failure rates for breeding in the absence of such intervention. |
URL: | http://www.tandfonline.com/doi/abs/10.1080/00063659709461052 |
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