Mismatches between breeding success and habitat preferences in Hen Harriers Circus cyaneus breeding in forested landscapes

Authors

  • MARK W. WILSON,

    Corresponding author
    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • BARRY O’DONOGHUE,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    2. National Parks and Wildlife Service, Ballynabrennagh, Tralee, Co. Kerry, Ireland
    Search for more papers by this author
  • BARRY O’MAHONY,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • CHRIS CULLEN,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • TIM O’DONOGHUE,

    1. National Parks and Wildlife Service, Ballynabrennagh, Tralee, Co. Kerry, Ireland
    Search for more papers by this author
  • GEOFF OLIVER,

    1. South Harbour, Cape Clear, Co. Cork, Ireland
    Search for more papers by this author
  • BARRY RYAN,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • PAUL TROAKE,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • SANDRA IRWIN,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • THOMAS C. KELLY,

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    Search for more papers by this author
  • JAY J. ROTELLA,

    1. Department of Ecology, Montana State University, PO Box 173460, Bozeman, MT 59717-3460, USA
    Search for more papers by this author
  • JOHN O’HALLORAN

    1. PLANFORBIO Programme, School of Biological Earth and Environmental Sciences, University College Cork, Enterprise Centre, Distillery Fields, North Mall, Cork, Ireland
    2. Environmental Research Institute, University College Cork, Lee Road, Cork, Ireland
    Search for more papers by this author

Corresponding author. Email: mark.wilson@ucc.ie

Abstract

During the past century, the upland breeding areas of Hen Harriers in Ireland have been extensively afforested. There is no evidence that this species avoids breeding in heavily forested landscapes and, indeed, young commercial forests in their second rotation are often selected as nest-sites. However, Hen Harriers have coexisted with these forested areas for only a few decades and it is possible that such landscapes are suboptimal. We examined the relationship between breeding success and habitat using a dataset spanning three years and four study areas in the south and west of Ireland. We assessed whether nest success and fledged brood size were related to habitat type, both at the nest-site and in the surrounding landscape. Neither measure of breeding productivity was related to total forest cover or to percentage cover of closed canopy forest in the landscape. However, in a subset of areas, high cover of second-rotation pre-thicket (young forests planted on land from which a first rotation has already been harvested) in the surrounding landscape was associated with low levels of breeding success. This may be due to factors related to predation, disturbance or prey availability. The fact that second-rotation pre-thicket is a preferred habitat for nesting in Ireland suggests that Hen Harriers may be making suboptimal decisions in the landscapes available to them.

Ancillary