Siskin - 2003-07

The Siskin is a small yellowish green finch which has a narrow pointed bill, yellow wing bars and patches at the sides of the tail. The male has a black cap and bib. The Siskin breeds among conifers, nests being built at the tops of trees, usually attached to outer hanging branches.

At the close of the 1984-88 survey less than 10 pairs were known to be breeding in Pembrokeshire, mostly in Pantmaenog Forest. An increase in numbers followed, being most marked in 1991 following an unusually large influx the previous winter. By the time of the 2003–07 survey they had reached an estimated average density of four pairs per occupied tetrad, suggesting the county breeding population had reached about 280 pairs. During and after the survey, considerable felling of conifer plantations took place and this will have eliminated a great deal of habitat favoured by Siskins, so the period of peak population has probably passed.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 6

Orange = breeding probable = 39

Yellow = breeding possible = 26

Total tetrads in which registered = 71 (14.5%)

Goldfinch - 2003-07

The goldfinch is common in areas of scattered trees and hedgerows, less dense woodland and gardens. It likes to nest in evergreen trees, particularly Cypresses.  Although the species has always been common, the population is somewhat cyclic, and is currently increasing.

From the 1984-88 breeding bird survey it was suggested that the population may be in the order of 4-6,000 pairs, based on a density of 15-20 pairs per tetrad. The number of occupied tetrads increased by 35% between the two survey periods. This is consistent with an increase of 39% shown by the BBS for the period 1994-2007, and there appears no reason to believe that our county population has behaved any differently than the national trend. This would suggest an increased current population, due to both an increase in density and distribution, giving a new figure of 6-8,000 pairs.

Richard Dobbins

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 95

Orange = breeding probable = 254

Yellow = breeding possible = 48

Total tetrads in which registered = 397 (81%)

Greenfinch - 2003-07

Due to changes in agricultural practices, the greenfinch is becoming less common in farmland. Parks and gardens with tall trees are now the preferred habitat for breeding, especially if evergreen trees are present. The prevalence of such trees in towns and villages may be encouraging the birds to move there.

It was estimated that 4–5,000 pairs were nesting in the county during the 1984-88 survey. The distribution found during the 2003-07 survey shows an increase of 47% in the number of squares recorded, with an in–filling within the existing widespread range rather than any expansion. The 1984-88 survey estimated the density at 15 – 20 pairs per tetrad, if that estimate is still true then the increase in occupied squares would indicate an increase in the breeding population to c. 6–7,500 pairs. The BBS assessment of a 27% increase in the population between 1994 and 2002 would broadly agree with this.

A cautionary note should be added at this time, in some gardens birds are suffering from an infectious disease which can be fatal. How this may affect future breeding populations we will have to see.

Richard Dobbins

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 69

Orange = breeding probable = 286

Yellow = breeding possible = 28

Total tetrads in which registered = 383 (78.2%)

Tree Sparrow - 2003-07

The Tree Sparrow is like a House Sparrow but is slightly smaller and has a chestnut coloured crown and dark cheek patches, the sexes being alike. It nests in holes in trees and buildings.

Historically this species has always been a sporadic breeder in Pembrokeshire. During the 1984-88 survey breeding was confirmed at Dreenhill, Penblewin and Pengawse. During the 2003–07 survey just one pair was confirmed as breeding, at Ramsey Island.

The Tree Sparrow has suffered long term decline across northern Europe, including Britain, probably as a result of changing agricultural practices.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 1

Orange = breeding probable = 2

Yellow = breeding possible = 0

Total tetrads in which registered = 3 (0.6%)

House Sparrow - 2003-07

The House Sparrow is known to most people, its extrovert character and strong association with habitation making it difficult to overlook. Nests are built in crevices, mostly in buildings but sometimes well-woven nests are built in shrubbery.

Those who took part in both the 1984-88 and 2003-07 surveys will have become aware of the increased number of breeding House Sparrows. Their distribution expanded by 11% and some colonies have grown. At the same time the urban numbers have decreased while suburban birds have flourished. Although modern and renovated housing has not provided suitable nesting holes, older stock and in particular farm buildings have provided favourable conditions. Between 1994 and 2007 the BBS calculated there was a 93% increase in Wales. The estimate of 3,500 pairs breeding in Pembrokeshire in 1988 is considered to have fairly represented the situation at that time. Applying the increase noted by the BBS to the distribution found by the 2003-07 survey, results in a new estimate of 7,500 pairs breeding in the county at the end of 2007.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 306

Orange = breeding probable = 79

Yellow = breeding possible = 27

Total tetrads in which registered = 412 (84.1%)

Starling - 2003-07

The Starling has been declining in Britain since the 1980’s, particularly in the south and west. The BBS notes a 53% decrease in Wales between 1994 and 2007. Comparing the results of the 1984-88 survey with that of 2003-07 shows a 69% contraction in range. There has also been a decrease within the surviving distribution. Just two pairs were breeding at Skokholm and none at Skomer, where there were 10 pairs and five pairs respectively in the 1980’s. This decrease was evident elsewhere in the county, for instance perhaps no more than five pairs survived in Haverfordwest and at Strumble Head a former thriving colony of 10 pairs was down to just one pair by 2004.

Combining the contracted distribution with such indications of decrease suggests that less than 200 pairs were breeding in Pembrokeshire at the end of 2007, whereas it was estimated there were 2,000 pairs in 1988.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 42

Orange = breeding probable = 16

Yellow = birds reported but with no signs of breeding

Total tetrads in which registered = 58 (11.8%)

Raven - 2003-07

Although Ravens are found mainly on the coast of Pembrokeshire, breeding on sea cliffs on the mainland and on the offshore islands, they occur quite widely in the open hilly areas and also across lowland farmland where there are suitable natural outcrops, quarries or wooded areas with mature trees for nest sites.

Raven nests are quite large bulky structures and most are usually not too difficult to locate. Within a territory they may utilise one of several alternative nest sites in a particular year. In some years old, unused nests can be taken over by other species such as Peregrines.

Using only confirmed and probable breeding categories, because of the likelihood of wandering non-breeding or foraging adult birds being included in the possible breeding category, Ravens were found in 133 tetrads during the 1984-88 atlas period. During the 2003-07 atlas survey, they were found in 144 tetrads, based on the same breeding categories, a small and probably insignificant increase of 8%. However, the proportion found at inland tetrads was higher, approximately 70 tetrads during 2003-07, compared with 57 tetrads in 1984-88, an increase of about 23%.

Donovan and Rees (1994) estimated that during the period 1984-88, the total breeding population was about 140 pairs. Of these 12 pairs were reported on the offshore islands, at least 65 pairs were breeding around the outer coast and the inland population was estimated to be about 60 pairs.

The locations of Raven nest-sites along the south Pembrokeshire coast were recorded during the most recent tetrad-based breeding survey (2003-07). This was done to help inform an assessment of the mainland coastal Raven breeding population during the latter atlas period. Occupied Raven nest sites were plotted on a map between Angle (Sheep Island) and Penally, a sample distance of a distance of about 42 km. (Haycock, unpublished data).

The average breeding population in this region in most years of the survey period was 12 pairs (about one pair every 3.5 km). The total length of coastline checked also included unsuitable habitat such as sandy bays/beaches etc, so the density is closer to one pair every 3 km if only suitable coastal nesting habitat is included.

If this linear density is representative of the whole of the Pembrokeshire coastline (estimated to be about 246 km long, based on the length of the National Trail on the open coast and the outer mainly cliff-sections of Milford Haven, as far up the waterway as Milford Haven and Pembroke Dock) then the mainland coastal breeding population could be as high as approximately 70 pairs. Numbers of pairs reported breeding on the offshore islands in 2003-07 were generally similar to those reported during the earlier atlas period.

Assessing the breeding density of the inland population is more difficult as, being quite widely dispersed, they are not so easy to census.  Most of the mature woodland and forestry blocks in the county are probably occupied by at least one pair.  As the number of inland tetrads with confirmed or probable breeding records appears to have increased over the last 20 years, assuming the original population estimate to be reasonable, then it is unlikely that the inland population is less than 60 pairs.

When combined with the coastal and island breeding pairs, a total population of not less than 140 pairs, and possibly up to 150 pairs seems quite a reasonable estimate.

Bob Haycock.

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 108

Orange = breeding probable = 36

Yellow = birds reported but with no signs of breeding

Total tetrads in which registered = 144 (29.4%)

Inland breeding tetrads= 70 (48.6% of breeding tetrads)

Carrion Crow - 2003-07

The all black appearance of the Carrion Crow means it is easily confused with the Rook. The curved bill and lack of a bare throat differentiates it from the Rook, as does the call and keeping its nest in a discrete territory rather than in a colony. The bulky stick nest, placed high in a tree, is usually conspicuous before leaves appear. In Pembrokeshire they also nest on cliff ledges.

The estimate that accompanied the 1984-88 survey was based on the distances between nests in a small number of random localities. With no other information available at the time, this was used to calculate a county total breeding population of 18,000–21,000 pairs. With the benefit of hindsight this is now considered to be an inflated total. The 1988-91 National Atlas showed Pembrokeshire contained Carrion Crows at maximum abundance and if their UK average density is adjusted to allow for this, suggests a county population of about 10,000 pairs, which seems realistic. The 2003-07 survey found no marked difference in distribution from the 1984-88 survey, so there has probably been no change in the size of the population.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 354

Orange = breeding probable = 51

Yellow = breeding possible = 48

Total tetrads in which registered = 453 (92.4%)

Rook - 2003-07

The Rook looks similar to a Carrion Crow but has a stepped forehead, a pointed bill, a grey–white area of bare skin around the base of the bill and loose flank feathers giving it a “baggy trousers” appearance. The large nest built of sticks is placed in the crown of a tree and several nests are grouped close to each other so that a colony is formed.

There have been many small shifts in the sites of rookeries in the county but no great change in overall distribution. Note the “Possible breeding” category has been omitted when assessing distribution, as Rooks recorded feeding in fields do not give any indication of the origin of their rookery. Site relocations have mostly been due to tree felling but in some cases are for unknown reasons. No complete county rookery census has been conducted during the last 30 years. 

Based on the three previous censuses a county population of between 8,000 and 10,000 pairs was extant over a period of 31 years. The BBS has indicated a 15% decrease in Wales between 1994 and 2007. However limited local surveys conducted over a period of 15 years in the 1980’s and 1990’s, showed fluctuations in annual totals but stability overall. On the information available, it seems reasonable to conclude that there has been no marked change in the Pembrokeshire breeding population and that a countywide census is desirable.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 211

Orange = breeding probable = 3

Total tetrads in which registered = 214 (43.7%)

Jackdaw - 2003-07

At the close of the survey of 1984-88 it was realized that the only assessment of breeding Jackdaw numbers anywhere in the county came from the islands of Skokholm and Skomer. An estimate of the population for the whole county had not previously been attempted. An assessment that an average of 20–30 pairs per tetrad was possible was used, postulating that there were 9,000–13,000 pairs breeding in Pembrokeshire. The 1988-91 National Atlas calculated an average density across the UK which was a little lower than the lowest value used for the initial local survey. The National Atlas also assessed relative abundance, the map of which showed Pembrokeshire at maximum. Making an adjustment to allow for this density suggests that the original estimate of 20 pairs per tetrad in the county was realistic. The BBS then indicated a 36%increase in Wales as whole between 1994 and 2007. No evidence was found that such an increase had taken place in Pembrokeshire but some sign that it has not.

Over the years there has been a 33% decline in the number breeding at Skokholm and a 66% decrease at Skomer. Studies on the islands have shown very low productivity even during times when breeding numbers increased there, meaning birds were being recruited from the mainland. The declining numbers which followed suggests such recruitment ceased, probably because there was no longer a surplus of birds on the mainland. With this in mind it seems best to be cautious and consider that county numbers had not increased. In this case the breeding population in Pembrokeshire at the end of 2007 was thought to have been about 9,000 pairs.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 361

Orange = breeding probable = 18

Yellow = breeding possible = 58

Total tetrads in which registered = 437 (89.2%)

Chough - 2003-07

Choughs, with their bright red legs and a red down-curved bill, are the rarest member of the crow family in Britain. Their population is mainly limited to cliff-coasts on the western seaboard of the UK and Ireland.

In Pembrokeshire they nest entirely in natural coastal cliff-crevices, and feed mainly in short-cropped (< 3 cm) maritime grassland swards, heath and dunes, but also utilise semi-improved pasture. Interfaces between vegetation, bare ground and rocky terrain are particularly important feeding areas. Choughs feed on soil invertebrates, such as leatherjackets, beetle larvae, ants and their larvae. In autumn and winter they will also occasionally take spilled cereal grain in coastal stubble fields.

 Pairs often mate for life and adults can live for 10 or more years. Sexual maturity can occur at two years old, but breeding success is more likely when three or more years old. Adult pairs occupy a territory; though will occasionally join more mobile flocks of non-breeding one to three year old birds.

Choughs have been well studied in Pembrokeshire, with annual population assessments since the 1990s; summary details being published in annual Pembrokeshire Bird Reports. Since 1963 they have also been the subject of national surveys approximately every ten years.

Records from tetrads suggest a decline in the overall distribution of Choughs between 1984-88 and 2003-07. However more detailed recording of the breeding population across the county suggests it has increased. This highlights some of the difficulties in recording this species at the tetrad level to try to determine changes in the whole population level. They are thinly spread in some tetrads but nest at higher density in other tetrads where there are key areas supporting optimal feeding and nesting habitat. 

Donovan and Rees (1994) considered that the Chough population was probably stable in the 20th Century but periods of severe weather caused temporary decreases. Decadal surveys in 1982 and 1992, registered a minimum of 51 and 58 pairs respectively. In the most recent national survey, 2002, the population had risen to approximately 62 territory holding pairs.

During the first decade of the 21st Century the population does appear to have increased slightly, possibly helped by a run of relatively mild winters and by positive management stemming from a “Pembrokeshire Chough Conservation Strategy “. This has included coastal grazing initiatives and management of recreational activities. By 2007, the number of pairs occupying territories had increased to 72, the highest recorded in Pembrokeshire. See Figure below.

Key areas for Choughs include Ramsey and St David’s peninsula, Castlemartin coast and Skomer, which are all within Special Protection Areas which form part of the Natura 2000 series of sites of European Importance. Breeding Chough populations in these areas are monitored regularly, together with surveillance of the non-breeding population.

From 1993 a small number of Chough nestlings were colour – ringed each year along the Castlemartin coast and on Ramsey. This study has provided details about movements between breeding territories and survival (Haycock, 2002).

 A small band of dedicated volunteers undertook annual recording, obtaining key local knowledge of their particular “patch”. Visitors have also provided valuable records and colour–ring sightings.

Bob Haycock

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 37

Orange = breeding probable = 6

Yellow = breeding possible = 10

Total tetrads in which registered = 53 (10.8%)

Magpie - 2003-07

A familiar bird to most people, the magpie can be encountered throughout the county and in most habitats. Its large stick nest, with its protective canopy, is obvious in the early spring before trees acquire their covering of leaves. 

The 1984-88 survey was accompanied by a population estimate of 22,000 pairs. As stated at the time, this was an extrapolation from a very small sample, and with the benefit of hindsight led to an inflated value. The 1988-91 National Atlas  showed that Magpies reached maximum abundance in Pembrokeshire, it also quoted densities of over 20 pairs per tetrad in farmland and 40 pairs per tetrad in woodland and suburban habitats. Applying these densities to the geography of Pembrokeshire and the distribution plotted by the 2003-07 survey, results in an estimated county total of about 10,000 breeding pairs.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 305

Orange = breeding probable = 81

Yellow = breeding possible = 59

Total tetrads in which registered = 445 (90.8%)