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Title: Status and ecology of the Priolo or Azores bullfinch, Pyrrhula murina
Author: Ramos, Jaime A.
Awarding Body: University of Oxford
Current Institution: University of Oxford
Date of Award: 1993
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I studied the seasonal variation in habitat selection, diet, food supply and food selection of the Priolo or Azores bullfinch, Pyrrhula murina. This species and its associated habitat, the Azorean native cloud forest, are poorly known and are threatened by afforestation and the invasion of exotic flora. In addition detailed studies of these aspects are lacking for oceanic island birds. Throughout this study a comparison between the ecology of the Priolo and that of mainland Bullfinches is made. The primary aims of this study were (1) to evaluate the importance of three alternative hypotheses in explaining the present distribution and abundance of this bird: habitat structure and composition, food availability and food preference, and (2) propose management strategies. Point-counts and capture-recapture indicate a population of 60 to 200 pairs. The bird breeds from mid-June to late August. Annual mortality was in the order of 45-50%. Stations were marked every 200 m along tracks covering all vegetation types in the area. These were walked three times a month to record presence or absence of birds per habitat type. The habitat structure and vegetation composition were recorded at these stations and used to explain the number of times a bird was detected at stations using logistic modelling. Diet was assessed from observations of feeding birds and faecal analysis. Food supply was examined from quadrats placed systematically within foraging habitats and from marked plots of winter food stocks. Food preferences were examined by comparing (a) availability and usage of foods in the field, (b) selected and rejected food items and (c) using food choice trials with captive birds. TTie importance of seed phenolics in explaining patterns of preferences for species and individual trees in winter was examined. The distribution of the Priolo was highly associated with native vegetation and its margins all year round. Other habitats were of marginal importance.The precision of habitat selectivity increased in the following direction: summer
Supervisor: Perrins, Christopher M. ; Bibby, Colin J. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Pyrrhula murina ; Ecology