Welsh Journals

A BREEDING BIRD CENSUS IN A SESSILE OAKWOOD AT ABER, CAERNARVONSHIRE R. G. GIBBS AND M. J. WIGGINGTON INTRODUCTION AND DESCRIPTION OF STUDY AREA A study was made of the bird population in 18 acres (7.28 hectares) of sessile oakwood during the 1968 breeding season, using a singing male mapping technique. The only published quantitative work on the bird population of such woods in Wales is that of Yapp (1955, 1962) who used a different technique, based on the line transect. The wood (see Fig. 1) was at Aber (SH/663717), 5 miles east of Bangor. It had an easterly aspect, and was situated on a 25-50° slope above Afon Rhaeadr-fawr, at an altitude of 250-600 ft. (76-180 m). Outcrops of rock appeared at intervals throughout the wood, which was grazed by sheep, mainly in winter. 35 nestboxes were sited in the Figure 1. — Map of Study Area. The four sub-areas shown are described in the text.