Rookeries survey 2013/2014

In 2011/12 it was commented on by several observers that some rookeries had either disappeared, or declined considerably in parts of Pembrokeshire.  In 2013 and 2014 birdwatchers were asked to count the nests in any rookeries they came across in the county.  No attempt was made to find all rookeries, or to visit all tetrads where rookeries had previously been recorded.

A minimum of 3,776 apparently occupied rook nests was recorded in 2013/14 from 138 rookeries surveyed. The largest rookery (at Dale) contained 178 apparently occupied nests (AON). The average rookery size was 27 AON.

Rookeries were recorded within 110 tetrads, which represented about 50% of the tetrads where rookeries were found during the 2003-07 Pembrokeshire breeding birds atlas survey (Rees et al. 2009). During the 2013/14 survey, rookeries were recorded from an additional nine tetrads where there was no evidence of breeding reported during the 2003-07 atlas survey period. However, all bar one of these had previously been confirmed to have breeding rooks in the first Pembrokeshire breeding atlas survey (1984-88) (Donovan & Rees, 1994).

At least fourteen rookeries were found to have 'disappeared'. These had ranged in size from 9 to 102 AON in a census of south Pembrokeshire rookeries undertaken in 1996 (Little and Level 1996). No alternative sites were found in the vicinity of these rookeries in 2013/14, although there was anecdotal evidence of two of them having attempted to relocate in the five years subsequent to their last being occupied.

If the population of 3,776 AON, from about 50% of the tetrads with confirmed breeding rooks in 2003-07, is a typical of the population across the remaining 50% of un-surveyed tetrads in 2013/14, then a total county population of at least 7,550 AON is possible. This assumes that the average rookery size in the un-recorded parts (e.g. in the northeast) is similar to that for the surveyed rookeries in the remainder of the county.  

Data from three previous censuses of the rook population (a BTO census of 1944-46, a Dyfed Wildlife Trust census of 1971 and a BTO census of 1975/76) suggested a population of between 8,000 and 10,000 pairs. 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. It was suggested that the population was still likely to be in this range in 2003-07 (Rees et al. 2009). Data from the 2013/2014 survey suggests a population closer to the lower estimate.

Orange squares show tetrads where rookeries were recorded in the 2003-07 atlas

Black circles show rookeries counted in 2013-14

Little Owl - 2003-07 breeding

Little Owls are found in open lowland country; they often perch in quite prominent positions close to nest sites and so are not quite as difficult to census, compared with the larger owls. According to Donovan and Rees (1994) Little Owls were thought to be increasing again following a gradual decline in the middle part of the 20^th Century.

Recent data suggest that there has clearly been a significant crash in their population during the years between 1984-88 and 2003-07. During the earlier atlas period, Little Owls were recorded in 31 tetrads, but from only six tetrads during 2003-07, an 81% decline. All atlas categories registered fairly large declines.

Donovan and Rees (1994) estimated that there were probably 50 pairs breeding in Pembrokeshire in the 1980s. During the recent atlas period, breeding was confirmed only on Skomer Island and on Ramsey Island. On the Pembrokeshire mainland they were recorded at just a thin scattering of widely distributed locations where breeding was not proven. 

Although this is an introduced species to Britain, first recorded in Pembrokeshire at Solva in 1920 (Donovan and Rees, 1994), the Little Owl is now one of our rarest breeding species.  Judging by the latest distribution maps, it would appear to be one we could lose, at least on the Pembrokeshire mainland.

Bob Haycock

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 1 

Orange = breeding probable = 2

Yellow = breeding possible = 3

Total tetrads in which registered = 6 (1.2%)

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)

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%)

Lesser-spotted Woodpecker - 2003-07

Despite their apparent scarcity, with usually only a handful of records received in any one year, the number of tetrads in which they were found was remarkably similar between the two atlas periods, 1984-88 and 2003-07. Whilst breeding was only confirmed in one tetrad, it is acknowledged that Lesser Spotted Woodpeckers are difficult to prove breeding and this decline was more or less balanced by the number of tetrads that registered probable and possible breeding evidence.

In the earlier atlas period, they were patchily distributed, with concentrations along the Western Cleddau river valley from around Millin Pill northwards. They were also reasonably well represented in tetrads further north, generally around the Teifi valley area, while another small concentration occurred in the south-east.

During the recent atlas period there was no evidence of breeding in the Teifi valley, although birds were present and no records at all from the south-east. They were recorded in the Western Cleddau but most records came from the Eastern Cleddau catchment. Whether this is due to a genuine contraction in range is not clear. Because this is a relatively difficult species to find, recorder bias cannot be ruled out. During 1984-88 there were no breeding records south of Milford Haven but breeding occurred between the two atlas periods at Orielton in 1995 (nest with young). In the 2003-07 period breeding may have occurred at Orielton again but was not confirmed.

Donovan and Rees (1994) suggested that Lesser Spotted Woodpeckers had been under-recorded and did not make an estimate of the Pembrokeshire population based on 1984-88 records. Assuming that the number of tetrads in which they were found reasonably represents the breeding population, this may be not less than 19 – 20 pairs in both atlas periods, suggesting population stability.

River-bank tree management may be an issue for this species, but conversely they may also be prospering from river corridor management, where bank-side woody vegetation has been fenced from grazing along lengths of river as part of riparian habitat management schemes. More survey effort is needed to determine breeding density in sample riverine habitat, as well as the relative status of the Western and Eastern Cleddau river valleys, apparently their core breeding areas.

Bob Haycock

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 1

Orange = breeding probable = 6

Yellow = breeding possible = 12 

Total tetrads in which registered = 19 (3.9%)

Great-spotted Woodpecker - 2003-07

The number of tetrads in which Great Spotted Woodpeckers were found increased significantly between 1984-88 and 2003-07, from 172 to 254 - almost 48%. With the exception of a small decline in the number of tetrads registering possible breeding, the number of tetrads where confirmed and probable breeding was recorded increased by around 67% and 122% respectively. According to BBS information the population index for this species has risen by 196% between 1994 and 2007 in Wales overall.

Donovan and Rees (1994) remarked that although much harder winters of the early 1960s apparently had no effect, the cold snap in winter 1979 was thought to have reduced the population substantially, based partly on observations at Hylton Woods. Since about 1990, there has been a remarkable run of generally mild winters so Great Spotted Woodpeckers may have prospered as a result.

By the end of the 1984-88 survey period, Donovan and Rees estimated that there was an average density of three or four pairs per occupied tetrad, providing a Pembrokeshire population of about 500 – 700 pairs. But they concluded that the population was undoubtedly greater prior to 1979. This woodpecker species is certainly one that currently seems to have prospered recently, and over the last 20 years seems to have recovered quite well.  Using the 1980s population estimate, based on the number found in tetrads, there may now be at least 760 to 1,000 pairs breeding in Pembrokeshire. 

Bob Haycock

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 75

Orange = breeding probable = 109

Yellow = breeding possible = 70

Total tetrads in which registered = 254 (51.8%)

Green Woodpecker - 2003-07

During the 20 year period between 1984-88 and 2003-07 there has been a quite dramatic decline in Green Woodpecker distribution across Pembrokeshire, indicated by a 77% decrease in the number of tetrads in which they were found. This decline is contrary to the BBS population index, which appears to indicate an overall 48% increase across Wales as a whole between 1994 and 2007. Within Pembrokeshire, the population appears to have shrunk towards the south and south-east. Apart from some outliers on the St David’s peninsula and in the Gwaun Valley, they now appear to have all but disappeared in the north.

Examination of the 1988-91 National Atlas is also revealing. Pembrokeshire and other counties in Wales (and also notably in Cornwall), recorded many more 10 km-squares with losses of confirmed breeding Green Woodpeckers, than  gains between the first national breeding birds atlas (1968–72) and the second atlas, 20 years later. This seems to much more closely represent the trends found in the local atlas, compared with the BBS population index. Even from the 1984-88 atlas survey, Donovan and Rees regarded the Green Woodpecker distribution as patchy across the county. They estimated that the average density may have been as high as one to two pairs per occupied tetrad and suggested a population then of about 140 – 280 pairs. Translating this to 2003-07 would therefore suggest a population of about 32 – 64 pairs. Even this seems to be a high number, considering how difficult they were to find during the five years of atlas fieldwork.

Up to 2007 at least, Stackpole National Nature Reserve, on the Castlemartin peninsula remained as one of their most reliable breeding areas, where one or two pairs regularly nested during the atlas survey period. Here there are still reasonably healthy ant populations in unimproved invertebrate-rich dune and maritime grassland, supporting yellow ant hills at a density of up to 550 per hectare. Green Woodpeckers feed over Stackpole Warren but have also been found searching for food in the limestone-crevices on the sea cliffs. 

Just why Green Woodpeckers appear to be in steep decline in Pembrokeshire is unknown. Recent on-line species maps, from the early period of the 2007 – 11 joint national winter and breeding atlas is also revealing. Provisional distribution maps suggest that there has been a contraction in their population in Wales. This is particularly evident in neighbouring Ceredigion to the north, where breeding evidence is fairly patchy and they also appear to be largely absent from west Carmarthenshire.

Is climate an issue? Could changes in grassland management have led to a loss of invertebrate prey, especially ants? Could this be subtly linked to local declines in the Rabbit population since the arrival of viral haemorrhagic disease in the early 1990’s, on top of already established seasonal outbreaks of myxomatosis? Have there been subtle changes in woodland management that may be a contributing factor? Whatever the reason or combinations of factors involved, further local research is needed to identify the main causes and to see if positive management can be introduced to halt the decline.   

Bob Haycock

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 3

Orange = breeding probable = 20

Yellow = breeding possible = 9

Total tetrads in which registered = 32 (6.5%)

Short-eared Owl - 2003-07

Short-eared Owls are very much birds of open rough grassland and heath, nesting on the ground usually under the shelter of heather, bracken or tall grasses. They will also breed in young forestry plantations. Areas with high populations of small mammal prey and a lack of disturbance, including disturbance from ground predators are key to their success.

Given these requirements, it is perhaps not really surprising that Short-eared Owls are a scarce breeding bird in Pembrokeshire and within Wales. Such “optimal” breeding habitat occurs mainly on the offshore islands.

Skomer is a long-established and regionally important breeding site for them, supporting up to five pairs between 1984 and 88, about 20% of the entire Welsh population at that time. In 1993 an unprecedented 12 pairs nested on the island. They also used to breed regularly on the commons of the St David’s peninsula where there are good stands of rough grassland and wet heath. The population appears to be fairly stable, compared with the 1984-88 period, though it fluctuates, probably depending on the density of vole populations.

During the 2003-07 atlas period between one and four pairs bred on Skomer and a single pair nested on Ramsey in 2005 for the first time since 1971. Breeding may also have occurred on Dowrog, where one was recorded carrying food in late May 2004 but breeding was not proven. Further sightings included a pair appearing to hold a territory on Dowrog in May 2006, but breeding did not occur.

Pellets analysed on Skomer have shown that although Short-eared Owls largely feed on young Rabbits and Skomer Voles, they may also take significant numbers of Storm Petrels, like the Little Owls breeding there.  Fifty-five pellets examined in 2007 produced 18 Storm Petrels, whilst Storm Petrels formed 31% of prey recorded in 13 pellets in 2004.

Bob Haycock

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 2

Yellow = breeding possible = 1

Total tetrads in which registered = 3 (0.6%)

Tawny Owl - 2003-07

Examination of the tetrad map suggests that the Tawny Owl breeding population distribution has thinned out in places over the last 20 years, especially across the more intensively farmed landscape with smaller amounts of woodland in the south of the county. However, there was evidence of higher tetrad occupancy in the east, and also on the St David’s peninsula where they were absent in the 1984-88 atlas period.

Overall there was a 21% decline in the number of tetrads in which they were found. The number of tetrads where presence only was recorded was down by 50% but the number of tetrads where probable and confirmed breeding was recorded was probably not significantly different between the two atlas periods.

The population stronghold currently appears to be in the more wooded Eastern Cleddau area and tributary valleys. There is a reasonably strong presence in the Gwaun and Cych valleys and also near the town of Pembroke. These apparent changes in distribution need to be treated with some caution. Being mainly nocturnal, they are a difficult species to record and so their distribution may be affected by observer effort bias. Added to the problem is the fact that both males and females will call from different parts of their territory and this could inflate the population estimate.

Donovan and Rees (1994) postulated that there were 4 – 5 pairs of Tawny Owls per occupied tetrad in Pembrokeshire during the 1984-88 atlas period. This produced an estimate of between 800 and 1,000 pairs across the county.

Observations of two areas, based on calling birds heard within 3 tetrads in woodland at Stackpole and within 2 tetrads at Pickle Wood and Minwear, were made during the 2003-07 period by Haycock, (unpublished data). This suggested a maximum breeding density in both areas of two and three pairs per tetrad respectively, about half the estimated total for the earlier period. Both these areas contain what is considered to be optimal breeding and feeding habitat.

1988-91 National Atlas notes the difficulties in estimating the population of this species due to their nocturnal behaviour. They suggest an average density of 10 pairs in each occupied 10-km square for Britain as a whole, based on 1988-91 National Atlas data and a national Tawny Owl survey (Percival, 1990). This provided a lower estimated population for Britain than previous national population estimates but was considered to be the best available at that time. However, it was based mainly on a single year national Tawny Owl survey when small mammal populations were low.

If two or three pairs per tetrad, from a small sample of only five tetrads, is typical of other tetrad densities where they were recorded in 2003-07, then this would provide a Pembrokeshire-wide estimate of between about 320 and 470 pairs.

Whether there has been a considerable reduction in the Tawny Owl breeding population is difficult to determine, for reasons given earlier. An apparent slight distribution increase in the east of the Vice-County may also reflect better recording effort in this area, and so may not represent a real shift. More survey work is required to determine if the 21% decline in the number of tetrads supporting Tawny Owls equates to a real population decline or just re-emphasises difficulties in recording this species. 

Bob Haycock

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 50

Orange = breeding probable = 79

Yellow = breeding possible = 30

Total tetrads in which registered = 159 (32.5%)

Little Owl - 2003-07

Little Owls are found in open lowland country; they often perch in quite prominent positions close to nest sites and so are not quite as difficult to census, compared with the larger owls. According to Donovan and Rees (1994) Little Owls were thought to be increasing again following a gradual decline in the middle part of the 20^th Century.

Recent data suggest that there has clearly been a significant crash in their population during the years between 1984-88 and 2003-07. During the earlier atlas period, Little Owls were recorded in 31 tetrads, but from only six tetrads during 2003-07, an 81% decline. All atlas categories registered fairly large declines.

Donovan and Rees (1994) estimated that there were probably 50 pairs breeding in Pembrokeshire in the 1980s. During the recent atlas period, breeding was confirmed only on Skomer Island and on Ramsey Island. On the Pembrokeshire mainland they were recorded at just a thin scattering of widely distributed locations where breeding was not proven.

Although this is an introduced species to Britain, first recorded in Pembrokeshire at Solva in 1920 (Donovan and Rees, 1994), the Little Owl is now one of our rarest breeding species.  Judging by the latest distribution maps, it would appear to be one we could lose, at least on the Pembrokeshire mainland.

Bob Haycock

Barn Owl - 2003-07

Barn Owls are thinly scattered across the county, mainly associated with farmland, particularly where there are good amounts of rough grazing. River valleys, such as those of the Western and Eastern Cleddau, are good areas for them. They mainly nest in farm buildings, including crevices in natural cliffs and quarries. Old semi-ruined buildings can also be important. Being a Schedule 1 species (under the Wildlife and Countryside Act) they are afforded extra protection measures, such locations need to be considered carefully in development planning applications.

They will readily utilise artificial nest sites provided in appropriate locations, including nest boxes placed in modern farm buildings or in trees. Being mainly nocturnal, Barn Owls can be difficult to locate. However, breeding adults can often be seen out hunting before dark when they are feeding young, gracefully flitting along hedgerows and grassy areas in search of rodents.

Due to recording difficulties, the atlas tetrad maps probably under-estimate their true distribution. Nevertheless, the number of tetrads in which they were recorded was actually very similar in both atlas periods.

With annual fluctuations in breeding success, mainly linked to cycles in vole populations, it is very difficult to estimate Barn Owl population levels without detailed study. It was considered that there were around 100 breeding pairs in Pembrokeshire in 1984-88, based on the number of tetrads where they were found. 

During the first atlas survey a large proportion of the records of Barn Owls came by talking to farmers, something that was also important during 2003-07.

With an absence of more detailed methods of estimating the population, the overall population is considered to be similar to that of the earlier period. The total number of tetrads with confirmed and probable breeding was higher than that of the earlier atlas period, so the actual breeding population may have been higher.

Since the 1980s, winters have been generally milder so winter survival of Barn Owls may also have improved. More detailed surveys are needed to refine ways of estimating population levels.

Bob Haycock

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 47

Orange = breeding probable = 18

Yellow = breeding possible = 36

Total tetrads in which registered = 101 (20.6%)

Cuckoo - 2003-07

Cuckoos were found in only 80 tetrads between 2003 and 2007 compared with more than 200 tetrads 20 years ago (a decline of about 62%). All atlas categories registered huge declines.

What is most apparent is that the population is now reasonably widespread only in the open country of the Preselis and on the St. David’s peninsula. Their recorded distribution here in 2003-07 was fairly similar to that of the 1984-88 atlas period. Both these areas probably support potentially good populations of ground-nesting host species (such as Meadow Pipit). They have all but disappeared as a regular breeding species in the south of the county and along the Teifi valley bordering Ceredigion. Surprisingly, Cuckoos appear to have declined along the Castlemartin peninsula where there are still good populations of potential host species within the extensive Military Range.

In 1984-88 it was assumed that the Pembrokeshire Cuckoo population was about 210 pairs (approx one pair per occupied tetrad). The most recently available figures from BBS (Wales) indicate that there has been a 52% decline in the Cuckoo population index between 1994 and 2007. According to a BTO Report (Say Goodbye to the Cuckoo), the national Cuckoo population showed a decline of more than 60% across the country during the period 1981-2006. Because of this population fall, Cuckoos have been added to the “red-list” of birds of conservation concern. The decline in the number of tetrads in which they were found in Pembrokeshire (62%) very much mirrors the national picture over the same period.

If the decline in Pembrokeshire is between 52% (based on the Welsh BBS results, albeit from only 56 sample sites across of Wales) and about 62% (based on the decline in tetrad distribution) – this would suggest a current estimated population of no more than 80-109 pairs, now largely confined to optimal habitat in the north of the County. Because Cuckoos calling in early spring may still be on migration, it is probably better to consider only those tetrads with probable or confirmed breeding evidence; this suggests a population of no more than 70 pairs in the recent atlas period.

The Cuckoo may be the victim of a variety of factors. They may be struggling to find enough food during the breeding season here in the UK and also suffering a similar fate on their wintering grounds in Africa. Declining habitat quality may also be affecting host species such as Meadow Pipit and Dunnock (species also showing signs of decline nationally) and thus affecting the ability for Cuckoos to rear a sufficient number of young each year needed to maintain a stable population.

Bob Haycock

 

Fieldwork 2003-07 (based on 490 tetrads)

Red = breeding confirmed = 1

Orange = breeding probable = 69

Yellow = breeding possible = 10

Total tetrads in which registered = 80 (16.3%)