Kestrel numbers within the county have declined and are now considered to be at their lowest level since 1894. The reasons for the decline are discussed in detail. Much of the decline is attributable to loss of suitable breeding habitat due to changes in farming practices, but there are also other contributing factors. Productivity seems sufficient to maintain a viable breeding population, but many successful breeding sites become unoccupied in subsequent years. This indicates that either adult survival between breeding seasons is too low, or insufficient recruitment is taking place due to low survival of first winter birds following independence, or perhaps both.
A likely cause of the low survival of first winters is again change in farming practices reducing the foraging quality of the arable landscape but this assumes that Pembrokeshire kestrels disperse to lowland arable areas to over winter in line with the national trend (Shrubb 1993), an assumption for which there are no data to help validate. Predation cannot be ruled out as a cause of poor over-winter or post-fledging survival, but during the breeding season it appears to be insignificant. Competition for nest sites may occur inland and the provision of artificial sites in some areas may help, but it is concluded that nest site competition in not a significant factor that is driving the population decline, and until other factors are understood and mitigated for, then the kestrel population will not increase significantly in response to provision of artificial nest sites.
The number of tetrads in which Kestrels were recorded, all categories, decreased from 156 to 97 between the two atlas survey periods. This 38% decline is likely to be genuine; the Kestrel is an obvious bird and is unlikely to be overlooked. The decrease has also occurred across all three categories. Using the confirmed and probable figures combined, the estimate for the breeding Kestrel population in Pembrokeshire is 30 to 35 pairs. This figure is backed up by the results of a dedicated census in 2008 which returned 31 breeding territories. A decline has also been recognised across the UK, particularly so in the southwest, and this decrease has also been accompanied by a decrease in productivity with fewer chicks fledging per nesting attempt (BTO nest record scheme).
A study in Kielder Forest, Northumberland, showed that predation by Goshawks caused a severe decline in the breeding Kestrel population (S. Petty 2003). The reasons for the decline in Pembrokeshire’s Kestrels are not known for certain but an investigation which began in 2008 showed early signs that predation of nesting adults was occurring and brood size for 10 nests was significantly lower than the national average. It is also suspected that competition for nest sites with the larger and dominant Peregrine is an issue, particularly at coastal cliff and inland quarry sites.
A nest box scheme in Pembrokeshire was initiated in 2007, in an attempt to alleviate potential nest site competition but it is too early at the time of writing to assess its effect on the Kestrel breeding population. Given the widespread decline in the west of UK, it would seem that the Kestrel’s future is insecure in Pembrokeshire.
Both Mathew (1894) and Lockley et al. (1949) noted the Kestrel as a common resident. In 1920 Lloyd stated that it was not so common in Pembrokeshire as the Buzzard, of which there were probably about 100 pairs at that time. Pembrokeshire has changed considerably since then, post-war agricultural activities having eradicated much of the rough ground. Breeding Kestrels are now confined to the less intensively farmed areas, the offshore islands and coastal strip, the Preseli Mountains, industrial sites and remnant bogs and moors. We estimate the total breeding population to be about 50 pairs.
They are more widespread in the winter. There is no hard evidence that our Kestrels are migratory though they have wandered as far out to sea as the Smalls. Up to 30 gathered on Skomer in September 1986.
The most numerous of all our Hawks, to be met with all over the county, nesting in woods, in old ruins, and in many places on the cliffs all round the coast. The Kestrel was common in our plantations at Stone Hall, and an old Crow’s nest was generally occupied by it, and we have taken some very pretty varieties of its handsome eggs. One summer we witnessed a conflict that was maintained for several days between a pair of Crows and a pair of Kestrels for the possession of an old nest in a hedge-row elm: it ended in favour of the Kestrels, and a brood was successfully brought off.
One bitter day we started a Kestrel off the snow-covered ground, and seeing it drop something as it flew off, went up to the spot and found a partly devoured Starling. We do not believe that Kestrels attack small birds unless they are unable to procure mice or insects, or are driven hard to find food for their young, when we have known them to carry off young Pheasants. One very foggy day, we shot a Kestrel by mistake, as it was fluttering low through the bushes, when we took it for a Woodcock. On picking it up, we found it had a diseased mandible, and was little more than a skeleton, having evidently been unable to feed.
We have found a pair of Kestrels at every station of cliff birds we have visited, whether on the mainland or on the islands.
Falco tinnunculus – CUDYLL COCH – Breeding resident Kestrel numbers within the county have declined and are now considered to be at their lowest level since 1894. The reasons for the decline are discussed in detail. Much of the decline is attributable to loss of suitable breeding habitat due to changes in farming practices, but […]
Falco tinnunculus – CUDYLL COCH – Breeding resident Comparison with previous atlas: 1984-88 2003-07 Breeding confirmed 26 21 Breeding probable 30 15 Breeding possible 100 60 No of tetrads occupied 156 (of 478) 96 (of 490) Percentage of tetrads 32.6% 19.6% The number of tetrads in which Kestrels were recorded, all categories, decreased from 156 […]
Falco tinnunculus – CUDYLL COCH – Breeding resident 1984-88 Breeding confirmed 26 Breeding probable 30 Breeding possible 100 No of tetrads occupied 156 (of 478) Percentage of tetrads 32.6% Both Mathew (1894) and Lockley et al. (1949) noted the Kestrel as a common resident. In 1920 Lloyd stated that it was not so common in Pembrokeshire as the […]
Falco tinnunculus – CUDYLL COCH – Breeding resident The BTO winter atlas showed that Kestrels were present in most 10km squares during the winters of 1981-82, 1982-82 and 1983-84. The darker the colour, the higher the relative total count for each 10km square. The darkest blue represents over 3-4 birds. More about the Kestrel in Pembrokeshire