Relative Abundance of the Azorean Buzzard Buteo Buteo Rothschildi and its Responses to Land Use

Abstract

Summary. The relative abundance of the Azorean Buzzard Buteo buteo rothschildi, both temporally and spatially, was assessed to determine its land use preferences and to support its conservation. The main aims were to compare its relative abundance between years, islands and localities and to relate these to land use in the context of habitat changes. Randomly selected plots were surveyed using two sampling methods: strip transect and point counts, to record any buzzards seen during the breeding season and to assess land use characteristics. The buzzards were most numerous on the largest island (São Miguel), and least numerous on the smallest one (Graciosa), as expected. However, we did not find significant differences in abundance among localities in Graciosa or between years in both islands. We only found local variation in abundance on S. Miguel. The overall population stability clearly favours the conservation of this Azorean endemic subspecies. Finally, we found that buzzards avoid industrial areas, urbanisation, natural vegetation and agricultural land, a finding that should be kept in mind by policymakers. These results may be used for landscape planning and management by authorities. There are several regional Management Plans with a spatial dimension but for land use classification the Municipal Master Plans have the discretionary power to classify urban and rural areas. Therefore, this information should be integrated into the decision process of the local classification actions. Future studies should include further habitat variables to assess their relationships with buzzard abundance, but also to extend the analyses to the remaining Azorean Islands in order to understand more deeply how this insular raptor responds to habitat changes. The results of these studies should strengthen law enforcement on land use sustainability and help to promote awareness among managers, landowners, stakeholders and the general public. —Lopes, M., Pereira, D.G., Afonso, A. and Melo, F. (2019). Relative abundance of the Azorean Buzzard Buteo buteo rothschildi and its responses to land use. Ardeola, 66: 343-360.