Jay - 2003-07

The Jay is a medium-sized bird which is pinkish-brown in appearance, with blue and white wing patches, black tail and white rump. Despite its striking appearance, the Jay is shy and retiring and its presence is often first revealed by its raucous call. It is found in woodland and mature gardens, placing its nest close up to the trunks of trees or among thickets of ivy or thorns.

An estimate of 600 pairs breeding in Pembrokeshire was made at the close of the 1984-88 survey, based on an average density of three pairs per occupied tetrad. The 1988-91 National Atlas used an average density of four pairs per tetrad when calculating the UK total breeding population. The relative abundance map in that book indicates that this value might well have been applicable to Pembrokeshire. This would have elevated the county total to 800 pairs. The BBS charted a decrease of 14% across Wales between 1994 and 2007 and the survey of 2003-07 returned a 6% increase in distribution in the county. Applying the BBS value to the 2007 county distribution, results in an estimate of 730 pairs breeding in Pembrokeshire at the end of 2007.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 31

Orange = breeding probable = 85

Yellow = breeding possible = 96

Total tetrads in which registered = 212 (43.3%)

Treecreeper - 2003-07

Field experience during the 1984-88 survey suggested an average density of five pairs per tetrad, from which a county total of 1,000 nests was calculated. The figure derived from the 1988-91 National Atlas  was marginally lower. The BBS assessed there was a 21% decrease in Wales between 1994 and 2007, which if applicable to Pembrokeshire suggests a breeding population of a little less than 800 pairs at the end of the 2003-07 survey. Winter survival of Treecreepers decreases with an increase in wet weather. The trend towards wetter winters in Wales during the past fifteen years may well be at least part of the explanation for the reduced breeding population.

Graham Rees

 

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 64

Orange = breeding probable = 95

Yellow = breeding possible = 38

Total tetrads in which registered = 197 (40.2%)

Nuthatch - 2003-07

The Nuthatch is a sedentary bird, so it is likely that all summer records are of breeding birds. The estimate at the end of the survey of 1984-88 was made on this premise, suggesting an average density of three to four pairs per tetrad and a county population of 600 – 800 pairs. The higher of these figures accords with the average density used by the 1988-91 National Atlas  to calculate the UK population.

Since then the BBS has indicated a 76% increase in Wales between 1994 and 2007. If the BBS findings are applied to the number of occupied tetrads registered by the survey of 2003-07, using a density of four pairs per tetrad, a population estimate of 1,500 pairs in Pembrokeshire emerges.  

 Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 84

Orange = breeding probable = 109

Yellow = breeding possible = 21

Total tetrads in which registered = 214 (43.7%)

Marsh Tit - 2003-07

The Marsh Tit has a glossy black cap and bib and lacks a wing bar. It is mostly found in deciduous woodland, nesting in natural holes, usually in trees.

The county breeding population was estimated to lie in the range of 500 – 700 pairs at the close of the 1984-88 survey. This was based on an estimated average density of three to four pairs per occupied tetrad, which attempted to allow for there being a wide variation between the number to be found in the largest blocks of deciduous woodland and lesser numbers in smaller areas of occupied suitable habitat. Since then Marsh Tit populations have declined both in the UK and across Europe, probably due to poor productivity and competition with other tit species.

The 2003-07 Pembrokeshire survey revealed a 16% decrease in distribution, compared to the BBS’s 12% decrease between the years of 2000 and 2005. The Pembrokeshire BAP Bird Survey of 2003 found a range of densities equivalent to 0.8–8 pairs per square km where this species was found.

Although the area covered was too small to be taken as representative of the county as a whole, it did illustrate that the approach resulting in the 1984-88 estimate was reasonably based. If the 16% decrease is applied to this estimate, it suggests a county breeding population of between 440 and 590 pairs at the end of 2007.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 39

Orange = breeding probable = 72

Yellow = breeding possible = 34

Total tetrads in which registered = 145 (29.6%)

Willow Tit - 2003-07

The Willow Tit has a black cap and bib like the Marsh Tit but the cap is dull, not glossy, and it has a pale wing panel. It also has a distinctive, irascible sounding, “chay - chay” call. Willow Tits inhabit boggy thickets and damp woodland where dead and rotten branches enable them to excavate their nest holes.

According to the BBS the Willow Tit decreased in the UK by 65% between 1994 and 2004, from what was considered to be a stable population in the 1980’s. It was estimated that there were 200 – 300 pairs in the county at the close of the 1984-88 survey, based on an estimated density of two to three pairs per occupied tetrad.

The 2003-07 survey found their Pembrokeshire distribution had decreased by 54%, suggesting there were about 120 pairs by the end of 2007. The most likely causes of decline are competition with other tit species, increasing nest predation by Great Spotted Woodpeckers, and deterioration in the quality of woodland as feeding habitat for Willow Tits (www.bto.org/birdtrends2006/wcrwilti.htm)

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 7

Orange = breeding probable = 30

Yellow = breeding possible = 12

Total tetrads in which registered = 49 10%)

Coal Tit - 2003-07

The county breeding population was estimated to lie in the range of 500–700 pairs at the end of the 1984-88 survey. This estimate tried to make allowances for the disparity between densities in conifer plantations and those found elsewhere. It assumed a density of 50 pairs per tetrad in conifer plantations and two to three pairs per tetrad elsewhere. Subsequent experience suggested this under estimated the occupation of non-conifer habitats. This resulted in a lower mean density than the UK average used in the 1988-91 National Atlas, which also showed a relative abundance map showing Pembrokeshire as having a lower than national average. Scaling this proportionally suggests the county figure could have been about 1,100 pairs at that time.

The BBS found there was a 16% reduction in population in Wales between 1994 and 2007, which if applied to the revised 1988 figure for Pembrokeshire, suggests there were about 900 pairs during the 2003-07 survey. However clear felling of conifer plantations took place during the years of the 2003-07 survey which must have reduced Coal Tit numbers. This is not reflected in the survey returns, for some plantations were surveyed before the fellers moved in. To what degree the Pembrokeshire breeding population has been reduced has yet to be evaluated, requiring future study.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 70

Orange = breeding probable = 120

Yellow = breeding possible = 19

Total tetrads in which registered = 209 (42.7%)

Great Tit - 2003-07

It was estimated that there were 13,500 pairs breeding in the county at the end of the survey of 1984-88, based on an estimated average density of 35 pairs per tetrad. The 1988-91 National Atlas calculated an average density of about 26 pairs per tetrad and their abundance map showed Pembrokeshire holding about average abundance. This suggests the county population was about 10,100 pairs at that time.

The Pembrokeshire survey of 2003-07 showed a 9% increase in distribution and the BBS showed a 34% increase in numbers for Wales. Applying these findings indicates there were about 14,700 pairs breeding in Pembrokeshire at the end of 2007.

As with the Blue Tit, increased winters survival in response to widespread garden feeding will have contributed to the increase in the breeding population.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 260

Orange = breeding probable = 131

Yellow = breeding possible = 30

Total tetrads in which registered = 421 (85.9%)

Blue Tit - 2003-07

It was estimated that 24,000 pairs were nesting in Pembrokeshire at the end of the 1984-88 survey, based on a mean value of 60 pairs per occupied tetrad. This was a similar level to that of the 1988-91 National Atlas, using the calculated national average and relative abundance distribution.  

Little distributional change was apparent by the conclusion of the 2003-07 survey but the BBS indicated there had been an increase of 29% in Wales between 1994 and 2007. Accepting that a similar increase took place in the county, the population at the end of 2007 was probably about 31,000 pairs. Widespread garden feeding resulting in increased winter survival was undoubtedly a contributing factor to increased breeding numbers.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 311

Orange = breeding probable = 95

Yellow = breeding possible = 23

Total tetrads in which registered = 429 (87.6%)

Long-tailed Tit - 2003-07

Suffering high mortality during severe winters, the breeding population during the 1984-88 survey was considered to be below optimum because of the effects of the cold winter of 1979. Numbers showed signs of recovery during the period of the survey and by 1988 it was estimated that between 1,100 and 1,600 pairs were breeding in the county, based on there being an average of six to eight pairs per occupied tetrad. The 2003-07 survey took place following a long period of mild winters and showed a 16% spread in distribution. The BBS findings suggested there was a 58% increase in Wales between 1994 and 2007, which if applied to the 2003-07 distribution gives an estimate of 2,500 breeding pairs in Pembrokeshire by the end of 2007.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 134

Orange = breeding probable = 53

Yellow = breeding possible = 39

Total tetrads in which registered = 226 (46.1%)

Pied Flycatcher - 2003-07

Pied Flycatchers were first proved to breed in Pembrokeshire, at Ffynone, in 1978 but they may have bred at Llancych in 1936. Colonisation of Pembrokeshire took place in the late 1970’s and 1980’s and the 1984-88 survey estimated the county population was about 100 pairs by 1988. Since then the population has undergone a decrease, so by the time of the 2003-07 survey there had been a 39% contraction in its county distribution. Even during the course of the survey there was known contraction, those breeding at Blackpool Mill Leat in 2003 having disappeared by 2004. It is estimated that 30 pairs were nesting in Pembrokeshire by the end of 2007. Pied Flycatchers decreased in the UK by 49% between 1996 and 2006 according to the BTO, early indications being because they have not adapted to peak food availability being advanced as a result of the trend towards earlier springs. Consequently the Pied Flycatcher has been amber-listed under the Birds of Conservation Concern 3 (Eaton et al., 2009). 

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 4

Orange = breeding probable = 15

Total tetrads in which registered = 19 (3.9%)

Spotted Flycatcher - 2003-07

This is a species that has been declining in the UK since at least the 1960’s. The BBS calculated a decrease in excess of 50% by 2007. The Pembrokeshire survey of 1984-88 estimated a total of 900 pairs breeding in the county, based on an average of four pairs per occupied tetrad. The 2003-07 survey found there had only been a contraction of 7% in distribution. The Pembrokeshire BAP Breeding Bird Survey of 2003 found numbers were still high in old woodland, albeit the survey scope was small. It would seem that Spotted Flycatcher numbers in the county may have decreased to a lesser degree than the 37% calculated by the BBS for the UK as a whole between 1995 and 2006. Applying the BBS value to the 2003-07 distribution for Pembrokeshire suggests that about 500 pairs were breeding during the 2003-07 survey.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 66

Orange = breeding probable = 107

Yellow = breeding possible = 35

Total tetrads in which registered = 208 (42.5%)

Goldcrest - 2003-07

The Goldcrest suffers high mortality during severe winter weather. This was experienced in 1979, affecting the breeding population during the 1984-88 survey, when it was estimated that there were about 5,000 pairs by 1988. There were no severe winters thereafter up to and including the time of the 2003-07 survey. During this survey a 33% increase in distribution was detected, despite clear felling of some conifer plantations, probably because most had been surveyed before felling took place. The BBS found there had been a 14% increase in numbers in Wales in 2006–07, which if applied to Pembrokeshire suggests the population had risen to about 6,000 pairs during the survey of 2007 but this is likely to decrease following the loss of so many conifer plantations.

Graham Rees

Fieldwork 2003-07 (based on 490 tetrads) 

Red = breeding confirmed = 72

Orange = breeding probable = 249

Yellow = breeding possible = 11

Total tetrads in which registered = 332 (67.8%)