Buzzard - 2003-07

The distribution of Buzzards recorded during the two atlas survey periods is almost identical and the number of registrations 398 (405) is also very similar. Estimating the number of breeding pairs of Buzzards is fraught with problems. Many of the birds which are seen displaying and even lining a nest are non-breeding birds and studies indicate that only 25% of the population actually breed. Also a pair may frequently line more than one nest.

In their prime habitat of fairly well-wooded undulating countryside they can reach densities of up to 0.88 pairs per km2 (Simms et al 2001). Much of the east of the county can be considered to be perfect habitat, but in the more open and exposed west, breeding density is likely to be lower. If an average density is assumed of two to three pairs per tetrad over 250 tetrads in the east and one pair per tetrad over 150 in the West, then a population range of 650 to 900 pairs breed within the county, a considerable increase from the 1984-88 estimate of 250.  Increases of this order have been recorded at a UK level but the Welsh population has remained stable since 1994 (BTO website).

Given that the range has remained unchanged between the two survey periods then at least some of this increase may be explained by variation in the methods used to make the estimate.

Paddy Jenks

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 124

Orange = breeding probable = 167

Yellow = breeding possible = 107

Total tetrads in which registered = 398 (81.2%)