BTO Research Report No. 55
THE ABUNDANCE AND DISTRIBUTION OF WILDFOhIL AND WADERS ON CARIIARTHEN BAY ( mr I ryhrr /crlrENDRAETH )
by
R. P. Prys-Jones and p. E. Davis
A report, from t,he British rrust for ornithology to the Nature Conservancy Council
March 1990
urM\ ABSTRACT
The report draws on information from the Long-termtsirds of Estuarjes Enquiry (BoEE)month Ly counts, from speciaL studies carried out during wjnter 1987/88, from unpubLishedcounty records and from the avaiLab{e Literature jn order to provide a comprehensive assessment of current knowLedgeof the abundanceand wintering distributjon of wi LdfowLand waders throughout the CarmarthenBay estuarine system.
The intertidaL bird fauna of the Carmarthentsay BoEE site is possibly Less weLLdocumented than that of aLmost any other Large estuarine area in Britain. The episod'ic, unstandardjzed and incompLetenature of BoEEcounting at this site over the years makes reLiabLe assessment of the reguLar wintering popuLation difficuLt and precLudes usefuL anaLysis of passage popuLations. Even for the winter period, most data reLate to the estuaries of the Taf, Tywi and Gwendraeth,(the "Three Rivers") with onLy very sparse information from the contiguous sandy beaches of Pendine Sands and Cefn Si dan.
Comparisonof winter BoEEcounts for the faf, Tywi and Gwendraeth from the earLy 1970s and mid 198Cs suggests onLy Limited changesjn popuLations present, with Oystercatchers apparentLy having decLined on the Taf and probabLe increases having occurred in SheLduckand Redshanknumbers on the Tywi/Gwendraeth. The most notabLe intertidaL bi rd popuLation current Ly reguLarLy wintering within the Three Rjvers is a nationaLLy important one of Oystercatcher. The area has a funther significance as a ccLd weather refuge for certain species, e.g. l.Jigeon. Cefn Sjdan reguLarLy supports a nationaLLy'important wintering popuLation of SanderLing and, on occasion, nationaLLy important numbers of Bar-taj Led Godwit, aLthoughthese Latter bj rds probabLy onLy appear episodicaLLy from the neighbouring Burry InLet. OveraLL, the Carmarthen Bay BoEEsite probabLy supponts a reguLar wintering popuLation of about 11500 wiLdfowL and 12r5OOwaders, the Latter totaL weLL exceeding the 101000 required for nationaL importance. The SandenLing popuLation is probabLy the second Largest on any U.K. estuarine site, and more comprehensive counting might weLL reveaL it to be of internationaL importance. Another species for which Carmanthen Bay is parti cuLarLy important, the CommonScoter, predominantLyoccurs offshore and so h,asnot covered in the present study.
The speciaL studies in winter 1987/88 reveaLedthat most of the Carmarthen Bay site is important for one or more of the species present, making it difficuLt to singLe out discrete areas as being of especiaL consenvation signi ficance. Two areas worthy of particuLar mention, however, are the importance of SaLmonPoint Scar, at the junction of the Tywi and Gwendraeth, for 0ystercatcher jn particuLar and of Cefn Sidan and, probabLy, Pendine Sandsfor SanderLing. Treatment of the entire site as a singLe unit for conservat'i on purposes wouLd appear desi rab Le, as the re i s undoubtedLy considerab Le i nterchange of thei r bi rd popuLat i ons; some bi rds may a Lso treat the site as a complexwith the Burry InLet.
CONTENTS
Page
ABSTRACT
CONTENTS
1. INTRODUCTION
2. AIMS 3
3. STUDYAREA AND METHODS 4
4. POPULATIONSPRESENT IN I^,INTER B
4.1 THE CONCEPTSOF NATIONALAND INTERNATIONAL IMPORIAN C E
4.2 THETAF
4.3 THETYWI/GWENDRAETH 12
4.4 CEFNSIDAN 13
4.5 OVERALLIMPORTANCE OF THE CARMARTHENBAY 13 SITE
5. INTRA-SITESPECIES DISTRIBUTION PATTERNS 1B
5.1 SHELDUCK 1B
5.2 t.lIGEON 18
5.3 TEAL 18
5.4 MALLARD 1B
5.5 RED.BREASTEDMERGANSER 22
5.6 OYSTERCATCHER 22
5.7 RINGEDPLOVER 22
5.8 GREYPLOVER 22
5.9 LAPh'ING 22
5.10 KNoT 22
5.11 SANDERLING 22
5.12 DUNLIN 27 Page
5.13 BLACK-TAILEDGODI.IIT 27
5.14 BAR-TAILEDGODI'JIT 27
5 .15 CURLEhI 27 \27 5.16 REDSHANK
5.17 TURNSTONE 27
6. SYNTHESISAND CONCLUSIONS 32
7. ACKNOTdLEDGMENTS 33 g. REFEREN CES 34
9. APPENDI CES 35 List of Figures
Figure &- Page
1.1 The CarmarthenBay BoEEsite, showing its current 2 protection by meansof three Sites of SpeciaL Scientific Interest.
3.1 The CarmarthenBay BoEEsite, showing pLace names mentioned in the text.
3.2 Count sectors adopted for the speciaL studies in winter 1987/88.
5,1 Average usage of each count sector by SheLduckduring 19 winter 1987188,expressed as a percentage of overaLL site usage by the species.
5.3 Averageusage of each count sector by TeaL during 20 winter 1987/88, expressed as a percentage of overaLL site usage by the species.
5.4 Average usage of each count sector by MaLLardduring 21 winter 1987/88, expnessedas a percentage of overaLL site usage by the species.
5.6 Averageusage of each count sector by 0ystercatcher 23 during winter 1987188, expressed as a percentage of overaL L si te usage by the speci es.
5.9 Averageusage of each count sector by Lapwingduring /+ winter 1987/88, expressed as a percentage of overaLL site usage by the species.
5.10 Averageusage of each count sector by Knot during 25 winter 1987/88, expressed as a percentage of overaLL site usage by the species.
5.11 Averageusage of each count sector by SanderLing 26 during winter 1987/88, expressed as a percentage of overaLL site usage by the species.
5.12 Averageusage of each count sector by Dunlin during 28 winter 1987/88, expressed as a percentage of overaLL site usage by the species.
5.14 Averageusage of each count sector by Bar-taiLed Godwit Zg during winter 1987/88, expressed as a percentage of overaLL site usage by the species. Page
5.15 Averageusage of each count sector by CurLewduring 30 winter 1987188,expressed as a percentage of overaLL site usage by the species.
5.16 Averageusage of each count sector by Redshankduring 31 winter 1987/88, expressed as a percentage of overaLL site usage by the species. List of TabLes
TabLe trr Page
4.1 QuaLifying LeveLsfor nationaL and jnternationaL 9 i mportance.
4.2 Estimates of intertidaL bird popuLations present 10 in winter (Nov-Flar)on the Taf estuary.
4.3 Estjmates of intentidaL bi rd popuLations present 11 in winter (Nov-Mar) on the Tywi and Gwendraeth estuaries-
4.4 H'ighest monthLy average counts f rom the specjaL 14 1987/88 winter studies for Cefn Sidan and for Cefn Sidan and Tywi/Gwendraethcombined.
4.5 Estimates of intentidaL waterfowL popuLations 16 present in winter on the overaLL CarmarthenBay site, based on BoEEcounts and the speciaL 1987/88 studies.
List of Appendjces
Appendix No. Page
9.1 Peak counts for each sector recorded during 35 the speciaL studies, November1987 to February 1988.
9.2 Average counts for each sector recorded 36 during the speciaL studies, NovemberlgBT to February 1988.
9.3 Scientific namesof species mentjoned jn 37 the text.
9.4 Average monthly BoEEcounts in winter 38 (November-fvlarch)f or the peri od November 1982 to November 1987 on the Taf and Tywi/Gwendraeth.
9.5 MonthLyaverage counts for the Taf and 39 the Tywi/Gwendraethfrom the speciaL studies carried out betweenNovember 1982 and February 1988.
9.6 MonthLy peak counts for the Taf and the 40 Tywi/Gwendraethfrom the speciaL studies carried out between November198T and February 1988.
9.7 Monthly counts for Cefn Sjdan from the 41 speciaL studies carried out betweenNovember 1987 and March 1988.
1. INTRODUCTION
The intertidaL bird fauna of the estuaries of the Taf, Tywi and Gwendraeth (51.45N, 4.25W), which together with the contiguous sandy shores of Cefn Sidan and Pendine Sands comprise the Carmarthen Bay Bi rds of Estuari es (BoEE) Enqu'iry si te, i s possibLy Less weLL documenterjthan that of a Lmost any other Large estuarjne area in Britain. This is in spite of the fact that the nature conservation importance of the system has been cLearLy recognjzed. The intertidaL fLats, marsh and dunes of TywynGwendraeth on the south side of the Gwendraeth estuary t,leredesjgnated as a grade 2 Nature Conservatjon Reviewsite by RatcLiffe (977). Figure 1.1 outLines the systemrs current protection by meansof three Sites of SpeciaL Scientifjc Interest (SSSI). A fourth SSSI, Marros-Pendinecoast, is adjacent to the western end of the system, and a fi fth SSSI, Burry InLet, is adjacent to its eastern end. ProposaLsare currentty in hand to extend the current LaugharneBurrows SSSI into a Pendjne and LaugharneBurrows SSSI which wiLL be separated from the Marros-Pendjnecoast sssl onLy by pendjne viLLage beach.
The present report has been produced in the Light of the nature conservation importance of the system, the Lack of readi Ly avai LabLe, up-to-date information on i ts bi rd popuLations, and the increasing threat to jt of potentiaL deveLopments. It is aimed at providing a baseLine of information regarding the recent abundanceand djstrjbution of the wader and wi LdfowL popuLations present, on which more detai Led studjes commissionedin reLation to specific deveLopmentproposaLs may be grounded. =tl
Craig Ddur/WharIey Point CIif f s Q SSSI ., 2/
Laugharne Burrows ff
GWENDRAETTI
PENDINE SANDS
Pembrey Coast SSST sand flats CEFN STDAN LJ saltmarsh N o 2 ,l KMS
Figure 1 .1 The carmarthen Bay BoEE si-te, showing its current protection by means of three Sites of Special Scientific Interest. The western end of Pendine Sands, including Gilman point and Witchett Pool, is omitted (see text). 2. AIMS
The study had three major aims: j) To analyse avajLabLe recent BoEEdata in order to providq a baseLine jnformation of on the wintering popuLations of wi LdfowLand waders present on the CarmarthenBay site. i i ) To evaLuate patterns of usage of key i nterti daL areas of the CarmarthenBay site by wi LdfowLand waders during winter lg\ll88. iji) To synthesize the information obtained to provide an assessmentof the conservation importance of the CarmarthenBay sjte to wiLdfowL and waders -
3. STUDYAREA AND METHODS 'incompLete The epi sodi c, unstandardized and nature of BoEE counti ng on the CarmarthenBay site over the years makesreLiabLe assessmentof its reguLar wintering bi nd popuLations extremeLydiffi cuLt. A numberof approaches are therefore used in the present report, the reLative merits of which are discussed as appropriate. A necessary precursor, however, to any consideration of the avaiLabLe counts is definition of the optimai area which they shouLd in theory encompass. Prater (1981) has provjded an overview of the physicaL and bioLogicaL characteristics of the site, and key pLaces within it mentioned in the text beLoware mappedon Figure 3.1.
To their east, the estuaries of the Taf, Tywi and Gwendraeth are Ljnked to the Burry Inlet BoEE site by the Long, wide, sandy beach of Cefn Sidan; there is thus no naturaL boundary of rocky, open coast separating these two systems- BoEE coverage of the south-west corner of this Linking area, comprising the creeks and marsh of PembreyBurrows west to the coastguard (51.41N' Lookout 4.17W)' has traditionaLLy been as part of the Burry InLet counts- The practicaL uti Ljty of this approach has recentLy been underwritten by the incorporation of PembreyBurrows into the proporld Burry InLet Ramsar/SPAsite, and consideration of jts bird popuLations was incLuded in a recent comprehensivereview of waterfowL abundanceand djstribution on (Prys-Jones the Burry Inlet et 4. 1989). This therefore provides a conVenientboundarybetweentrreffi1aLthoughcLearLyLeavingopenthe question as to whether on ornithoLogicaL grounds it rnight be better to treat Burry InLet and CarmarthenBay as a single systeml this point wiLL be returned to in the Synthesis and ConcLusionschapter. The remainder of Cefn Sidan, north-west from the coastguard Lookout, thus faLLs within the CarmarthenBay site, but in practice onLy the roosting birds at jts northern tip, TywynPoint, have been incLr:dedin BoEE counts, and even these are normaLLy counted f rom the north bank of the GwenqJraeth.
At its western end, a Less ambiguousboundary to the CarmarthenBay site is provided by the western end of Pendjne Sandsat Gi LmanPoint (51.44N, 4.33VD; j th s i s the western ext remity of a cont'inuous, wide, sandy beach sl netchi ng from the mouth of the Taf. In practice, however, the a."i west cf Ginst Point at the mouth of the Taf has very seLdombeen included in BoEEcounts due both to problems of access and Lack of counters. It rnlasaLso not covered in the speciaL studies in winter 1987/88 (see beLow) and has therefore been omitted from the maps incLuded in this report to save space.
BoEEcounts are usually madenear to high tide on a weekend date near the mjddLeof each month chosen to coincide with spring tides. FuLL detai Ls of generaL BoEEmethodology and the rationaLe behjnd it are provjded by prater (1981). (November-March) lr|inten coverage of even the centraL "Three Rivers,, part of the CarmarthenBay site, j.e. the Taf, Tywi and Gwendraethestuanies between Ginst Point in the west ai?-Tywyn Point i; the east, has howeverbeen very erratic. 0n both the Taf and Tyw'r, counting during the 1970s h,as confined aLmost entineLy to 1969/70 and 1970/71; on the Gwendraeth, additionaL coverage was achieved in 1974/75 and 1975/76. Dur.ing the 19g0s, the Taf was covered from 1982/83 to 1986/87 inc Lusive, a Lthough not necessari Ly comprehensivetyand not at aLL in somewinter rnonths; coverage of both the Tywi and the Gwendraethrlas restricted to 1986/81, hbwever. The onty months during the 1980s whenessentiaLLy compLetecoverage of the Taf, \- \ Coed Farn
Delacorse
L 1a n BIack Scar Lausha"\+ Ferryside Whar 1e Y \Po i n t \S'-\ \ -J.
Cinst Point Point
Kidwelly
\
sandflats lll saltmarsh N Pembrey Country Park 0 2 t Pembrey rtl kms
Iookout --r
Figure t 3. The carmarthen Bay BoEE site, showing place names mentioned in t'he t,ext. The wesLern end of pendine sands, including Gilman Point and witchett poor, is omitt,ed (see text). Tywi and Gwendraeth estuaries was achieved h,ereNovember 1986 and lgBT and March 1987.
A counters' meeting was organized in May 1987 in LLaneLLi with the aim of pLacing counting at the site on a consistent and comprehensivebasjs for the future. UnfortunateLy, however, no standard BoEEcount data at aL1,have been submitted to the BT0 fon any month after l.lovember1987, aLthough some LeveL of counting effort has continued sjnce then. D. Roberts (in Ljtt.) has kindLy madeavai LabLeestuaries data f rom the Carmarthenshire collrff-records for the period December 1987 to December 1988 incLusive, but these are LargeLyuncoordinated counts and sightings and as such must be interpreted with care. Renewed attempts at BoEE count organization in 1g8g wi LL hopefuLLyensure future coverage fncm the start of 1990.
During winter 1987/88, a programmeof speciaL studies on the bird popuLations of the Taf, Tywi and Gwendraethestuarjes llas organjzed by the tsTg Estuaries Unit and carried out by Peter Davis of the ir|CCtlaLes Field Unit. The Taf ',as divided into five sectors (A-E on F'igure3.2) and the TywilGwendraethinto (F-K six on Figure 3.2). Fet'lbirds h,erepresent in the intervening gap to the south-east of tlharLey Point (P. Davis, pers. obs.). Each estuary ,uas counted on at Least 10 days spread between the start of Novemberand the end of February with, on average, two counts being madeper sector per day. The great majonity of counts h,ere conductedduring Low tide, j.e. f rom four hours before Low water unti L four hours af ter ({. erys-jon6d-et aL. 1g19l, and thus provided information not onLy on numbeE of intertidaLFl-s present but aLso on patterns of estuarine use by the various species. In addjtion, Cefn Sidan was spljt into four sectors (L-O on F'igure3.2) and an effort made to obtain monthLy Lowtide counts for these from November1987 to March 1988 incLusive. Access to sector L, Lying withjn an RAFbombing range, posed a particuLar probLemand coverage of it was onLy achieved on three occasions. Breakdownsof the peak and average counts recorded for each species jn each sector are provided in Appendices9.1 and g.z respectiveLy.
In Chapter 4t assessmentis madeof the winter popuLation sizes of waterfowL species within the Carmarthen Bay site. Comparisonis rnadeof popuLation estimates from BoEEcounts conducted in the earLy 1970s and mid 1980s, and the recent tsoEEdata aLso comparedwith information derived from the spec-iaL winter 1987/88 studies and from the 1987/88 county records. gffshore sea duck, notably CommonScoter, are excLudedas neither the BoEEcor:nts nor the speciaI studies couLd adequateLy cover them. ALL assessment from BoEE coverageof recent winter popuLations is madeusing h'ighest average monthLy counts, as used by Prater (981), based on aLL 1980s data, rather than the normaLcurrent practice of using average peak winter counts over the most recent five-year period (outLined jn SaLmon et aL. 1989). Under most circumstances, the Latter technique resuLts :ii-T[ightLy higher popuLation estimates, pnobabLybetter approximat'ing the average maximumusage of a site (see Prater 1981t pp 129-130, for discussion of this poini). However, becausethe Taf, Tyw'i and Gwendraethestuaries have been comp[eteLy covered in onLy three BoEEcounts during the 198Cs, in each case at the beginning or end of a winter whenpopulations tend to be Lower than in mid wintei, use of average peak winter counts resuLts in an arti fj ciaLLy LowoveraLL popuLatjon estimate. This point is eLaborated on in chapter 4.
Scientific namesof aLL species are given jn Appendix 9.3. \i \ i
GWENDRAETH
r:t sand flats ll CEFN SIDAN E--=] t-l saltmarsh
N 012 I kms )';,' o
Figure 3.2 count sectors adopted for the speeiar st,udies in winter lglTl88. 4. POPULATIONSPRESENT IN WINTER
4.1 THE c0NcEPTS0 F NATT0NALAND rI'TTERNATToNAL TMpoRTANcE
Criterja for internationaL importance have been agreed by the C,ontnacting Panties to the Ramsar Convention. Under one criterion, a wetLand is 'important considered internationaLLy if it reguLanLy hoLds 1)4 of the indjviduaLs in a popuLation of one species or subspecies of waterfowL, whiLe any site reguLarLy hoLding a totaL of 201000or more waterfowL (wiLdfowL and wadens)aLso quaLifjes (RamsarConvention Bureau 1988). Britainrs wi LdfowL beLongto the north-west EuropeanpopuLation (Pirot et aL. 1989) and the waders to the east AtLantjc f Lyway popuLation GTt g piersma 1989). A wetLand in Britain is considered nationaLLy important 1'f it reguLarLy hoLds 1Y.of the estjmated tsritish popuLation of one species or subspecies of waterfowl, whi Lu"any sjte hoLding a totaL of 51000 or more wi LdfowLor 101000 or more waders aLso quaLjfjes (Prater 1981). The currentLy accepted natjonaL and internationaL quaLifying LeveLsused in this report are taken from SaLmon et aL. (989) and summarized in TabLe 4.1 . These criteria reLate to friln,lFica L i mportance, which i s most re Levant to the present report ; there arez of course, additionaL reasons why a site may be nationaLLy or internationa LLy i mportant-
4.2 THETA F
TabLe 4.2 summarisesestimates of the waterfowL popuLations reguLarLy present jn on the Taf winter during the earLy 1970s (from tsoEEcounts), the mjd 1980s (from jn BoEEcounts) and winter 1987/88 (from the speciaI studies)r ds welL as giving peak recorded winter counts for the period betweenNovember 1987 and December1988 (from the speciaL studies and county records), MonthLy breakdownsof the 1980sr BoEE data and of both average and peak counts derjved from the 1987/88 speciaL studies are provjded in Appendices9.4, 9.5 and 9.6 respectiveLy.
tri LdfowLpopuLation estimates f or the earLy 1970s and mid 1980s are simj Lar, but the estimated wader popuLation of ca 31300 birds on the Taf in the mid 1980s is Less than haLf that of the earLy 197Cs (TabLe4.2). ALmost aLL of this decLine can be accounted for in terms of substantjaLLy Lower popuLation estimates for just three species, Oystercatcher, GoLdenPLover and Lapwing. Oystercatchers on the Taf are LargeLy dependenton cockLes from the beds on the Lower west side of the estuary, whereason the Tywi/Gwendraeth,where no major decLine i s apparent (TabLe4.3), they depend LargeLy on musseLs(prater 1981). CockLes tend to be an intrjns'i caLLy more variabLe resource than musseLs,and a decLine in their overaLL avaiLabiLity nay have occurred on the Taf aLthough no pubLjshed evidence exists regarding this. The winter 1987/88 studies reveaLeda peak feeding popuLatjon on the Taf of just over 11600 Oystercatchers aLthough the highest average monthLypopuLation present 11as (TabLe under 11000 4.2)' and no counts exceeding 11300 are avaiLable from county records for the period December1987 to December1988. gveraLL, the evidence supports a reaL decLine having occurred in the Taf 0ystercatcher popuLation, but for unknownreasons-
The apparent decLines in GoLdenPLover and Lapwing popuLatjons are much more 9
TabLe 4.1 QuaLifying LeveLsfor nationaL and internationaL importance.
Nati onaL (G.8.) Internationa L
Mute Swan 180 11900 ['lhooper Swan 60 170 GreyLagGoose 11000 11000 Dark-beLLiedBrent Goose 900 1,7OO SheLduc k 750 z r5oo Wigeon 2,500 7,500 TeaL 11000 4,000 MaLLard 5r000 20r000't* Pintai L 250 700 ShoveLe r 90 400 Pochard 500 3,5OO CommonScoter 350 9r000 GoLdeneye 1s0 3r000 Red-breastedMergansen 100 11000
Oystercatcher 2r900 9r000 Avocet J* 700 Ringed PLover 2s0 500 GoLdenPLover 2r000 10r000 Grey PLover 210 1,500 Lapwing 10r000 20r000*'t Knot ?-,200 3r500 Sander^Ling 140 11000 PurpLe Sandpiper 160 500 DunLin 4 r3OO 14,0OO Ruff 15't 10r000 Snipe ? 10r000 BLack-tai Led Godwit 50 700 Bar-tai Led Godwit 510 1r000 Whimbre L + 700 CurLew 910 3r500 Spotted Redshank 2* ? Redshank 750 1r500 Greens han k 4* ? Turns tone 4s0 700
British popuLatjon too smaLLfor meaningfuLfigure to be obtajned.
Where1% of the tsritish wintering popuLation is Less than 50 b.irds, 50 is normaLLyused as a minimumquaLifying LeveL for nationaL importance. ** A site reguLarLy hoLding more than 201000waterfowL quaLifies as internat'ionaLLy important by virtue of the absoLute numbens. 10
TabLe 4.2 Estimates of intertidaL bi rd popuLations present in winter (Nov-Mar) on the Taf estuary.
Highest monthLy Highest average Highestaverage avenagecount from Peakwinter co monthLy BoEEcount, monthLy BoEEcount, speciaL studies, betweenNov 19 Nov 1969-l4ar 1976 * Nov 1982-Nov1987 Nov 1987-Feb 1988 and Dec1988 *
l{ute Swan 1 0 0 WhooperSwan 0 1 0i 12 t'Jhite-fronted Goose 4 0 0 'l 21 GreyLagGoose 6 0 12 CanadaGoose 0 0 0 13 BarnacLe Goose 0 0 0 50 Brent Goose 0 1 0 SheLduc k 170 15s 158 200 Wigeon 1?5 160 0 11000 GadwaLL 0 0 0 14 TeaL 1 8 58 119 MaLLard 180 177 448 599 Pintai L 70 12 0 6 ShoveLer 4 0 0 50 Eider 3 0 0 Long-taj Led Duck 1 0 0 3 CommonScoter ? 4 0 + GoLdeneye 0 0 1 2 Red-breastedMerganser 4 10 -_i ..: TotaL wi LdfowL: 564 530 66s
Oystercatcher 2 1204 673 966 1,610 Ringed PLover 23 31 5 36 GoLden PLove r 2r000 11250 0 31000 Grey PLove r 3 11 0 14 Lapwing 2 1525 425 472 no: Knot 0 2 0 SanderLing 0 1 0 DunLin 43s 301 40 3s0 Snipe 32 14 1 BLack-tai Led Godwit 10 3 0 1; Bar-tai Led Godwit 9 9 0 '202 43 Cur Lew 303 333 322 Spotted Redshank 0 0 0 3 Redshank 121 252 370 trg Greens h an k 4 0 1 Green Sandpiper 0 0 1 2 CommonSandpiper 0 0 1
TotaL waders: 7,669 3 ,305 2 r15g Tota L waterfowL: 81233 3,835 21724
From Prater & Rowe 9978), with additionaL information from prater (1981).
** From the speciaI studies and county records.
Large numbers(>11000) of CommonScoter present at times offshore not lncLuoeo. 11
jntertidaL TabLe 4.3 Estimates of bird popuLatjons present jn winter (Nov-t{ar) on the Tywi and Gwendraethestuaries.
Highest monthLy Highest average Highest average average count from Peakwinter co monthLyBoEE count, monthLyBoEE count, speciaL studies, betweenNov 19 Nov 1969-Mar 1976 * Nov 1982-Nov 1gg7 l,lov 1987-Feb 1988 and Dec1988 *
14uteSwan 2 1 0 0 Bewickts Swan 0 0 0! t.lhite-fronted Goose 4 0 0 : GreyLagGoose 0 0 0 21 tsrent Goose 0 2 0 50 SheLduck 45 389 130 144 tli geon 250 200 44 11000 GadwaLL c 0 0 2 TeaL 100 90 1?O 238 MaLLard 300 234 48 ,o: Pintai L 5 4 0 ShoveLe r 20 5 0 1 Pocha rd 1 7 0 1 Scaup 1 0 0 19 Eider 50 0 0 20 Long-tai Led Duck 0 0 0 1 CommonScoten 3 1 0 1?7 GoLdeneye 3 1 0 3 Red-breastedMerganser 50 22 6 12 Goosander 0 4 --: ..? TotaL wi LdfowL: 8s4 954 348
Oystercatcher ? 2559 21713 11809 2r574 Ringed PLover 55 34 15 ,t2 GoLdenPLover 475 550 0 Grey PLove r 21 49 5 17 Lapwi ng 1,697 1,264 825 11700 Knot 86 136 c SanderLing 250 70 1 CurLewSandpiper 1 0 0 : Purp Le Sandp'ipe r 0 0 0 1 DunLin 2 2337 11668 456 ,roo: Ruff 5 1 0 Jack Sn'ipe 1 1 0 Snipe ?0 42 0 BLack-tai Led Godwit 9 4 19 38 Bar-tai Led Godwit 99 525 164 300 CurLew 308 414 ?01 3?4 Spotted Redshank 4 3 0 1 Redsh an k 264 441 250 402 Greens han k 18 5 2 Green Sandpiper 2 4 0 : CommonSandpiper 1 1 0 3 Turns t one 164 63 19 70
TotaL wi LdfowL: 8 1386 7 ,ggg 3,766 g,220 Totat waterfowL: 8 1942 4,114 * From Prater & Rowe U978), with additionaL information f romPrater (1981 ) . ** From the speciat studjes and county records. 12
equivocaL. Winter movements of both species withjn tsritain are strongLy infLuenced by prevai Ling weather patterns (SaLmonet aL. 1988), and thej r numbersat any site tend thus to be highLy vEllGE-Le. In add'ition, both species are LargeLy dependenton saLtmarshand fjeLds adjacent to estuaries, rather than on the intertidaL fLats themseLves,and are thus particuLarLy prone to aLterations in popuLation estimates resuLting fncm diffetrences jn counting technique. Thus the speciaL winter 1987/88 stud'ies, focused strictLy on the intentidaL area, faj Led to record GoLdenpLover, which tend to concentrate on marshy fieLds insjde the seawaLLaLong the west side of the Taf; this omission very LargeLy accounts for the discrepancy betweenthe speciaL studies and recent BoEE counts in estimates of the totaL wader popuLation of the Taf (TabLe4.2). A count of 31000 Golden PLover near Ginst Point in earLy December1988 further indjcates that no Long-termdecLine js probabLe for th j s species.
The popuLations present of certain other species are cLearly not adequateLy reveaLed by BoEE counts as conducted to date. One of these i s the r,Jigeon, whosereguLar Lowwintening popuLation may be massiveLyaugmented for short jn periods, particutar as a nesuLt of severe weather, a feature aLso true of the neighbouring Burry and CLeddau estuarine systems (prys-Jones 1989, Prys-Jones et aL. 1989). An infLux of about 21000 Wigeonoccurred at BLack Scar in Late January 1987 foLLowing hard weather"(D. Stacey, in Litt.), and about1,000werepresentatDeLacorseinDecember1987(TabLeEnoBoEE counts hlere conducted on the Taf in either of these months. Another under-recorded species is the MaLLard, for whjch the Lowtirle studies in winter 1987/88 reveaL a popuLation more than double that frorn the recent BoEE counts. This probabLy resuLts from the tendency of the species to move over the seawalL onto marshy fields along the west side of the Taf at high tide (P. Davis, pers.obs. ) .
4.3 THE TYI.'IIGWENDRAETH
TabLe4.3 summarisesestimates of the waterfowL popuLations reguLarLy present on the Tywi/Gwendraethin winter during the earLy 1970s (from tsoEE counts), the mid 1980s (from BoEE counts) and in winter 1987188(from the speciaL studi es), as weL L as gi v'ing peak recorded winter counts f or the peri od between November 1987 and December1988 (from the speciaL studjes and county records). MonthLybreakdowns of the 1980s'BoEE data and of both average and peak counts deri ved from the 1987/88 speciat studjes are provjded in Appendices 9.42 9 .5 and 9 .6 respecti veLy.
As assessedby BoEEcounts, overaLL winter waterfowL popuLation LeveLson the Tywi/Gwendraethhave changedLjttLe between the earLy 1970s and mid 1980s (TabLe4.3); however, as the Latter data very LargeLyderive from a singLe winter, 1986187, thjs concLusionmust be treated with considerabLe caution. jncreases NotabLe are apparent for SheLduck,Bar-taiLed Godwit and Redshank, wheneassubstantiat decLines are indicated for species such as SanderLingand DunLin. LittLe weight shouLdbe attached to the changes in the Bar-taiLed Godwit and SanderLingtotaLs, however, as both are tikeLy to be a consequence of episodic infLuxes from the Burry Inlet and Cefn Sjdan (see sectjon 4.4).
The sr:bstanti a LLy Lower overaL L numbers of waterf owL recorded on the Tywi/Gwendraethby the speciaL 1987/88 winter studjes reLatjve to the recent 13
(TabLe BoEEcounts 4.3> are LargeLy a methodoLogjcaLartefact. As 1.1asnoted for the Taf data, onLy the tsoEEcounts incLude binds, notabLy Golden pLover and Snipe, which occur on fieLds adjacent to the estuary. In addition, however, bjrds recorded on the Tywi/GwendraethBoEE counts at the Tywynpoint roost incLude many individuaLs, in particuLar of Oystercatcher, DunLjn and j Bar-ta Led Godwit, which probabLy feed aLong Cefn Sjdan. Thii,, point js considered further in section 4.4 beLow.
As on the Taft occasionaL infLuxes of I'ligeonoccur on the Tywi/Gwendraeth, with 11000 off LLansteffan jn mid December1988 being the Largest recent (TabLe total 4.3). Sightings of up to 50 Brent Geeseand 20 Eider at the SaLmonPoint musseLscar, again in December1988, aLmost certainLy represent jnfLuxes from the Larger popuLations which are reguLarLy present at the western end of the Burry InLet (Prys-Jones5rt aL. 1989). Likewise, the 127 CommonScoter seen off Llansteffan in mid Jailffi 1988 must have resuLted jnto from a short-term movement the estuarine area from the popuLation of somethousands reguLarLy present jn winter out on the sea in Carmarthen Bay.
4.4 CEFNSIDAN
TabLe 4.4 presents peak monthLytotaLs of birds present during the Low tide counts aLong Cefn Sidan between November 1987 and March 1988. A monthLy js breakdownof the avaiLable counts provided in Appendix 9.7. ExcLudingthe Large numbersof CommonScoter, which are generaLLyweLL offshore and cannot be adequateLyassessed by Land-basedobservers, few wiL,CfowLare present, but about 51000 waders forage aLong the shore. Amongthese are particutarLy notabLe totaLs of SanderLingand Bar-tai Led Godwit, aLthough the dependency of these two species on the area in fact differs markedLy. Bar-tajLed Godwit numbersonLy uncommonLyexceed 200 bi rds (Davis 1984;r, simi Lar to the popuLation frequentty present on the Tywi/Gwendraethand possibLy the same bjrds- The peak count of over 500 birds noted in December1987 therefore very probabLy represents an infLux of the popuLation frcm the neighbouring ',mobj Burry InLet, where Bar-taj Led Godwit are known to be Le and unpredictabLe in their occurrence at Lowtide" (Prys-Jones et aL, 1989). By contrast, a very substantiaL SanderLingpopuLation js cLear[FEsident aLong Cefn Sidan throughout the winter, with peak numbersof 11000 or more on occasion (Davis 1984, Morgann.d.).
ALso shownon TabLe4.4 are highest monthLyaverage counts from the lgBZlBS winter studies for Cefn Sidan and the Tywi/Gwendraethcombined (sectors F-O incLusive on Figure 3.?). Comparison of these with the recent Tywi/GwendraethBoEE data presented in TabLe 4.3 impLies strongLy that most of the Oystercatcher, DunLin and Bar-taiLed Godwit that feed aLong Cefn Sidan moveto TywynPoint to roost, where they are included in BoEE counts, but that manyof the Knot and sanderLing appear not to do so.
4.5 OVERALLIMPORIANCE OF THE CARMARTHENBAY SITE
Two independent estimates of the waterfowL popuLation reguLarLy wintering on the Carmarthen Bay site can be madefrom the avaiLable data. one draws on the merged1980sr BoEE data for the Taf and Tywi/Gwendraeth which, as (section indicated above 4.4), appear to incLude a substantjaL proportion of 14
TabLe 4 -4 Highest rnonthLy average counts f rom the speciaL 1987/88 winter studies for Cefn Sidan and for Cefn Sidan and Tywi/Gwendraeth combined.
Cefn Sidanand Tyw'i/Gwendraeth Cefn Sidan combined
SheLduck 0 130 ['ligeon 0 44 TeaL 0 120 MaLLard 23 48 GoLdeneye 0 0 Red-breastedMerganser 17 _:t_ TotaL wi LdfowL: 40 363
Oystercatcher 1r800 21697 Ringed PLover 0 15 Grey PLover 20 25 Lapwi ng 0 825 Knot 600 600 SanderLing 675 675 DunLin 1,285 1,625 Snipe 0 0 BLack-tai Led Godwit 0 19 Bar-tai Led Godwit 612 627 CurLew 4 201 Spotted Redshank 0 0 Redshan k 0 250 Greenshank 0 2 Green Sandpiper 0 0 CommonSandpiper 0 0 Turnstone 0 19
TotaL waders: 4,996 7,580
TotaL waterfowL: 5 1036 7,943
NB Large numbers (>11000) of CommonScoter present at times offshore not included. 15
the bi rds which f eed a Long Cefn Sidan. The other makesuse of the spec'iaL 1987/88 winter studies on the Taf, Tywi/Gwendraethand Cefn Sidan combined. Both estimates wiLL be minima becausethey entireLy Lack data from pendine Sands, to the west of the Taf, and from Witchett PooL, a naturaL dune-sLack pooL present in LaugharneBurrows about 200minLand of Pendine Sands. TabLe 4.5 summarises the resuLts. Agreement as regards the overaLLuwaterfowL js popuLation encouragingLycLose, with the discrepancy of ca 1,25O birds being LargeLy accountabLe in methodoLogicaLterms. The BoEEcounts omjt ca 600 SanderLingand 450 Knot present on Cefn Sidan, whereas the 1997/8 studies missed the GoLden PLover (11800) and probabLy someCurLew (ca 350) uti Lizing marsh and fieLds adjacent to the intertidaL area. Correctifr!' the totaLs accordingLy impLies that the CarmarthenBay site reguLarLy supports about 11350 wiLdfowl and 111500waders jn winter, excLusive of birds present on Pendine Sandsand Witchett PooL.
For reasons aLready mentioned in Chapter 3, the wader popuLation estimate presented here from recent BoEEcounts is substantiaLLy greater than that of 6'711 birds published in SaLmonet aL. (1989). The present estimate is cLearLy the more reLiable onel--lf the "standard" technique faiLs to cope adequateLywith the epi sodic and incompLete data sets avai LabLe. The CarmarthenBay site is thus cLearLy of nationaL importance in terms of jts overaIL numbersof waders, hoLding substantiaLLy in excess of the 101000 quaLifying LeveL. In addition, it certainLy supports nat ionaLLy important popuLatjons of Oystercatcher and SanderLing (TabLe4.5). By contrast, the reguLar occurrence of Bar-tai Led Godwit in numbersexceeding the appropriate quaLifying LeveL is more doubtfuL, for reasons outLined in section 4.4. Davis U984) has previousLy suggested that CurLewan,l Redshanknay aLso be present in nationaLLy important numbers. This seemsunLikety for the former species, but very possibLe for the Latter. Redshanktend to be a difficuLt species to census comprehensiveLybecause of thei r habit cf "disappearing,' into creeks and saLtmarsh. NevertheLess, the combirredNovember peak counts f or t he Taf and the Tywi/Gwendraeth f rom the 1987/88 studi es trrtaL Led over 900 birds (Appendix9.6), weLL in excess of the appropriate quaLifying LeveL. As for Bar-tai Led Godwit, further studies are required to estabLish concLusi ve Ly the RedshankI s t rue s tatus.
What difference is the Lack of reguLar count data from Witchett PooL and Pendjne Sands LikeLy to make? Considering l^ljtchett PooL fi rst, recent summarjesof count jnformat'ion ane avaiLabLe in Davis (984), Morgan (n.d.) and Roberts & Morgan (n.d.), and a BoEEcount card ulas submitted for mid March 1987 by D. Roberts. Combiningthe information from these suggests peak wintering duck popuLations of up to 25 t,ligeon,15 GadwaLL,ca 400 TeaL, 65 MaLLardr90Shoveler, 100Pochardr 30 Tufted Duck and 50 Slaup. The reLationship between peak and reguLar numbersfor this site indicated by the 1968'70 data presented by Owenet aL. (1986) suggests that substantiaLLy Lowernumbers of most speciefE LikeLy to be present on a regular basis. In addition, doubLefigure numbersof Greenshanksometimes occur, and fLocks of GoLden Plover and Curlew may be present in the pooLrs vicinity. 0n Pendine Sands, the most notable wjntening wader counts appear to be up to 130 Knot, 350 SanderLing, 11000 or more DunLin and 75 Bar-tai Led Godw.it,aLthough the reLationship that these peak tota Ls have to reguLarLy occurring popuLations must remajn open to question.
In concLusion, one can onLy reiterate the assessment of Davis (1984) that 16
TabLe 4.5 Estimates of intertidaL waterfowL popuLations present jn winter on the overaLL carmarthenBay site, based on BoEEcounts and the speciaL 1987/BBstudies.
Highest average Highest monthLyaverage monthLy BoEEcount, count f rom spec'iaL studies, Nov 1982-Nov 1987 Nov 1987-Feb1988
Mute Swan 1 0 WhoopenSwan 1 0 GreyLagGoose 6 0 Brent Goose 2 0 SheLduc k 542 288 [,ligeon 360 44 TeaL 91 178 MaL La r"d 282 483 Pintai L 12 0 ShoveLe r 3 0 Pochard 7 0 CommonScoter 4 0 GoLdeneye 1 1 Red-breastedMerganser 29 22
TotaL wi LdfowL: 11341 1,016
Oystercatcher 3,O61t 3,613* R'inged PLo ve r 49 20 GoLdenPLover 11800 0 Grey PLover 51 25 Lapwi ng 11499 1,27A Knot 138 600 SanderLing 70 675t DunLin 1,765 1,639 Ruff 1 0 Jack Snipe 1 0 Snipe 44 1 ELack-tai Led Godwit 7 19 Bar-tai Led Godwit 525 627* CurLew 747 400 Spotted Redshank 3 0 Redshank 573 569 Greens han k 5 1 Green Sandpiper 4 1 CommonSandpiper 1 1 Turnstone 63 19
TotaL waders: 10,407 9,490
TotaL waterfowL: 11,748 10,496
* NationaLLy important popuLation ( see TabLe 4.1) . NB Large numbers (>11000) of CommonScoter present at times offshore not incLuded. 1T
"more comprehensive, systematic and fr"equent counting of the wader and 'is wiLdfowL popuLatjons of this coastLine cLearLy muchto be desired ....,,. Taking aLL avajLabLe information jnto account, it seemsreasonabLe to suggest a reguLar wintering popuLation for the entire site of about 11500 wiLdfowL and 12'500 waders- In addition, the popuLation of one individuaL species shouLd be highLighted. The reguLar occurrence of even 675 uintering SanderLing (TabLe4.5) wouLdmake CarmarthenBay the second best estuarine site for this species in the U.K., behjnd the major concentration present on (Salmon the Ribble et at. 1989). However,additionaL evidence of up to 350 birds aLong PendinE--5lnds, together with occasionaL counts of up to 11000 birds on Cefn Sidan aLone, points to the possibiLity that CarmarthenBay nay compr"jsean internationaLLy important wintering site for the specjes. This deserves cLoser investigation. 1B
5. INTRA-SITESPECIES DISTRIBUTION PATTERNS
The aim of thjs chapter is to use the resuLts of the speciaL 1987/88 studies to describe the winter distri bution patterns of the varjous wi LdfowLand wader species throughout the Taf, Tywi, Gwendraethand Cefn Sidanr,, mapping these f or species having peak counts exceed'ing100 bi rds (see nppendices g.6 and 9.7). Presentation on maps is standardized across species by expressing the average usage of each count sector by a species (see Appendix g.D; defined as the average numberof individuaLs present through the winter, as a percentage of the overaLL site usage vaLue for that species.
5.1 SHELDUCK
As on the neighbouring Burry Inlet (Prys-Jones et aL. 1989), SheLduck on CarmarthenBay were strictLy confined within TTFEtuari ne area and did not uti Lize the coastaL sandy shores (Figure 5.1). The major concentrations were on the Lower Taf and Gwendraeth,on both of whjch numbensjncreased markedLy after mid winter (see Appendix9.5); possibLy this was a resuLt of movement of bi rds f r"omBurry InLet, where the popuLatjon tends to peak jn mjd winter, decLining thereafter (prys-Jones et aL. 1989).
5.2 WIGEON
ALL the smaLLnumbers of ['ligeonobserved during the 1987/88 counts h,ere on sectors F and H of the Tywi estuary (Figure 3-2), aLthoughthere is aLso a reguLar, smaLLfLock of lrligeonnear BLackpooL bridge on the Taf estuary upstreamof the area covered by the 1987/88 counts (D. Roberts, pers.comm.). However,episodic Large infLuxes of over a thousand birds occur on both the (see Taf section 4.2) and Tywi/Gwendraeth(see section 4.3), and f Locks of over a hundred at times occur on the sea off Cefn Sjdan (Morgan& Roberts n.d.).
5.3 TEAL
'in Highest average numbersof TeaL cbserved winter 1987/88 h,ere aLong the upper Taf estuary and, in particuLar, aLong the eastern bank of the Tywi (Figure 5.3). The Lack of bi rds observed on the Gwendraeth js perhaps surprising in view of the extensjve saLtmarshareas avai LabLe, 'i aLthough the species s knownto be very variabLe in jts occurrence there (Davjs 1984;1.
5.4 MALLARD
(>100) AtL Large concentrations of MaLLard seen were on the Taf, in partj cuLar aLong i ts tower, north-eastern shore (Figure 5.4). Thi s correspondswith the previous observation of Davis 9984) that "MaLLardoften frequent the channeLs(of the Taf) under the cLiffs near l,lharLey poirrt and the sandbanksto the south.,' 1g
./oo/
o 15 o 6 -10 o 11-20 o 2]--35 'v o
t,-
sand flats saltmarsh
N t KMS
Figure 5.1 Average usage of each count sector by Shelduck during wint,er 1987/ BB, expressed as a percentage of overall site usage by the species. See Appendix 9 .2 for actual numbers of birds involved- 20
% o l_5 o 6 -10 ... o 1t--20 2I-35 oo
*"* l-
-l 1*
irr l, I sand flats l=-=l saltmarsh t--l-l I
N l kms
Figure 5 .3 Average usage of each count sector by Teal during winter lggT/gg, expressed as a percentage of overall site usage by t,he species. See Appendix 9 -2 for actuar numbers of birds invorved. % 15 6 -10 o IL_20 21-3 oo s t\
F:-l'l J,l l:l sand flats
F= t-l saltmarsh I *t
Nl lv t kms
Fisure 5'4 of each count secror,bv I;::::J":-" Mauard durins winrer-;;;;'.". 1987/88, s.eappenoi'i ;.:"i::"::f:"i'"il;::l'.;';:J:.f;":i"if 22
5.5 RED-BREASTEDI4ERGANSER
SmaLL numbersof Red-breasted Mergansers h,ere noted on a LL three r j ver estuaries, but were most reguLar just off the Cefn Sidan shore.
5.6 OYSTERCATCHER
Muchthe major feeding concentration of Oystercatchers, averaging weLL over 11000birds (sector I in Appendix 9.2), wasonthemusseLbedsof Salmon Point Scar, between the Tywi and Gwendraethestuaries (Figure 5.6). Birds from here roosted LargeLy at TywynPoint, whereas manyof the cockLe-feeding birds aLong the south-western shore of the Taf roosted at the nearer Ginst Point. Good numbers of feeding birds were aLso spread aLong the Cefn Sidan coast. Most of these probabLy roosted around TywynPoint, but more detaiLed studies might estabLish that some move across to t'Jhite.fordPoint and the neighbouring saLtmarshwithin the tsurry InLet.
5 .7 RINGED PLOVER
A f Lock of up to 30 bi rds h,aspresent aLong the Lower eastern shore of the Tywi, incLuding the SaLmon Point Scan area at the mouth of the Gwendraeth. ELsewhere,smaLLer numbers were episodicaLLy noted to the south of BLack Scar on the eastern s j de of the Taf . None h,as recorded a Long Cefn S'idan but, because the counts there r.lereconducted from the Lower shore, smaLLnumbers couLd possibLy have been overLookedon the upper shore.
5.8 GREYPLOVER
Within the Three Rivers, aLmost aLL bi rds noted h,ere on or around SaLmon Point Scar. In addition, smaLLnumbers were spread aLong Cefn Sidan.
5.9 LAPWING
substantiaLfLocks exceeding500 bi rds occurredat times aLong the midd Le and/or upper reachesof aLL three estuaries (Figure 5.9).
5,10 KNoT
lrlobi rds were observed feeding within the Three R'ivers, but up to ca 600 were noted aLong the middle part of Cefn Sidan (Figure 5.10). It 6lems very Likely that many or most of these moveto and from the tsurry Inlet, rareLy entering the estuaries of the Three Rivers to forage.
5.11 SANDERLING
Except for the odd small group at SalmonPoint Scar, not seen within the estuaries of the Three Rivers. In excess of 500 birds feed aLong Cefn Sidan (F'igure 5.11), someof which may welL moveat times to and f rom both pendine 23
% o 1s o 6 -10 O 11-20 oo 2I-35
lr-")-t*-1
i, il I :l sand flats
FI t-t saltmarsh -l I
N \J t kms
Figure 5 -6 Average usage of each counL sector by Oystercatcher during winter 1987/88, expressed as a percentage of overall site usage by the species. See Appendix 9.2 for actual numbers of birds involved. 24
% o 1s o 6 -10 o 11-20 oo 21-35
tiir'l sand flats p= l-l saltmarsh I _t
n N ^ kms
Figure 5 -9 Average usage of each count sector by Lapwing during winter 1gT7lBg, expressed as a percentage of overall site usage by the species. See Appendix 9 -2 for actuar numbers of birds invorved. 25
% o 1s ((- \ o 6 -10 o 11-20 21-35 oo
T; : -l*-')-
ll-'t L, . I sand flats tr-=l t-l saltmarsh _l I
n N rll l kms
Figure 5.10 Average usage of each count sector by Knot during winter j9B7/gB, expressed as a percentage of overall site usage by the species. see Appendix 9 .2 for aclual numbers of birds j-nvolved. 26
% o 1s o 6 -10 o TL_20 oo 21-35
't ,r'
tln sand flats
F= t-t saltmarsh *l t
N 0 llr t kms
Figure 5.11 Average usage of each count sector by Sanderling during winLer 1987/88, expressed as a percentage of overall site usage by the species - See Appendix 9 .2 for act,ual numbers of birds involved. 27
Sands to the west and trhi tef ord Sandsto the south-east (cf. prater 1g7l, Prys-Jones et aL. 1989).
5.12 DUNLIN
The Largest numbersof feed'ing DunLin occurred aLong Cefn Sidan, with another concentration in the generaL vicinity of SaLmon Point Scar (Figure 5.12>. Very few were present on the Taf, in accord with the commentof Davis (1984) that, other then Redshank"... the Taf is not noted for Large numbers of smaLLwaders."
5.13 BLACK-TAILEDGODWIT
A f Lock of up to just under 40 birds r.lasregularly present through the win.ter on the Lower Tyw't, generaLLyaLong the eastern shore in the vicjnity of Ferryside. These birds were seen nowhereeLse within the CarmarthenBay site and wouLdappear to be a separate popuLation frcm the sLightLy Larger numbers occurring in the Burry rnLet (Prys-Jones et aL. lg}g>.
5.14 BAR-TAILEDGODWIT
The Large numbers(>600) of Bar-tajLed Godwit which occasionaLLy frequent Cefn Sidan very probabLy originate from the tsurry InLet (see section 4.4), wheneasthis is unlikely to be so for the smalLer popuLation present on the (Figure LowerTywi 5-14). Here, numberswere Low (<50) untiL mjd winter but j rema ned reguLa r Ly a round fiO duri ng January and February. As with the BLack-taiLed Godwit, they were never seen on the Taf or Gwendraeth.
5 .15 CURLETJ
Ub'iquitous within the estuarjne area of the Three Rivers, but with major concentrations aLong the Lowenwest shore of the Taf and around SaLmonpoint Scar (Figure 5.15). VirtuaLLy unrecorded by the counts aLong Cefn Sidan.
5.16 REDSHANK tlideLy distributed within the estuarine area of the Three Rivers, but absent from Cefn Sidan (Figure 5.16) . Most abundant on the muddien areas, especially near and upstream of Laugharneon the Taf, as weLL as on the Gwendraeth.
5.17 TURNSTONE
Noted onLy on SaLrnon Poi nt Scar, where a f Lock of up to 70 was reguLa r Ly present. 28
% o 1s o o 6 -10 \^ -, \: o 11-20 21-3 s oo
n L.'i sand flats
t--tT---= saltmarsh l--i
N ,rl + KMS
Figure 5.12 Average usage of each count sector by Dunlin during winter lggTlBB, expressed as a percent,age of overall site usage by the species. See Appendix 9.2 for actuar numbers of birds involved. 2g
% o l-5 o 6 -10 o 11-20 oo 2f-3 5
t/
l.;'l t- . I l, I sand flats
i=-=l t-l saltmarsh _l I
+N kms
Figure 5.14 Average usage of each count sect,or by Bar-t,ailed Godwit during wint,er 19BT /88 , expressed as a percentage of overall site usage by the species. See Appendix 9.2 for actual numbers of birds involved. 30
% o 15 o 6 -10 o IL*20 -,9 o 21-35 \" o
jI* . ,l*-?*
Lrl I: .:l sand flats
l--l t-l saltmarsh
n N ltl l kms
Figure 5-15 Average usage of each count sect,or by Curlew during winter 19gT/BB, expressed as a percentage of overall site usage by the speeies. See Appendix 9.2 for act,ual numbers of birds involved. 31
%
\ ((- o I5 o 6 -10 o 11-20 oo 21-3 5
.: ff' {\ il' |'1i' tl l1' i
l'..irll I sand flats
i:- -l t-l saltmarsh I _r
N
llr l kms
Figure 5.16 Average usa8e of each count sector by Redshank during winter 1gg7 l}g expressed as a percentage of overall sit,e usage by the species. see Appendix 9-z for actuar numbers of birds invorved. 32
6. SYNTHESISAND CONCLUSIONS
The standardized count data currentLy avai LabLefor the Carmarthen tsay site are too Limited for any reLiabLe assessmentof reguLar passagepopuLations or for any attempt at revjewing tjme tnends in wintering popuLatjons. NevertheLess, anaLysis of the counts avai LabLefor the winter period have reveaLedthe site to be of consjderabLesignjficance to intertjdaL birds, with reguLar wintering popuLations of about 11500 wiLdfowLand 121500waders. Two species, Oystercatcher and SanderLing, are reguLarLy present in nationaLLy important wintering numbersl jn addition further studies might reveaL Bar-tai Led Godwit and Redshankas being sor and Golden PLover flocks at Least on occasion exceed the appropriate quaLifying LeveL. During severe weather",f Locks of 11000 or more I'ligeon nay aLso be present. Offshore, the CommonScoter mouLting and wintering popuLation on CarmarthenBay is cLearLy jcance of major signif (Owenet aL. 1986), but for Log'isticaL reasons outside the scope of thi s study. Beffiassessrnent of the sanderLing popuLation, LargeLy confined to the extremeLy poorLy censusedsandy beachesof Cefn Sidan and Pendine Sands, wouLd appear to be a priority. The popuLation present seemsLikeLy to be the second Largest cn an estuarine BoEEsite in the U.K., and thorough coverage might weLL reveaL it to be of jnternationaL si gnj fi cance.
The distribution mapspresented in Chapter 5 reveaL a situatjon in whjch most of the si te i s i mportant for one or more species, making jt di ffi cuLt to singLe out discrete areas as being of especiaL conservat'ionsignif i cance. One exception is SaLmonPoint Scar (sector I on Figure 3.2), at the junction of the Tywi and Gwendraeth, which is clearLy the key to the presence of a nationaLLy important 0ystercatcher popuLation, as weLL as being utj i.ized by a diversity of other species (see Appendices9.1 and 9.2). Treatment of the Taft Tywi and Gwendraethestuarjes as a singLe unit for conservatjon purposes wouLdappear desi rabLe (Davis 1984), as there is undoubtedLyconsiderabLe interchange of their bird popuLatjons/,aLthough this nay be reLativeLy Less frequent in the case of the Taf than for the Tywi and Gwendraeth(cf. prater 1981). SimiLarLy, the Linking of Cefn Sidan with the Three RlTers wouLd appear to be appropriate as manybirds from both areas appear to roost at TywynPoint. However, resuLts from counts jndicate that Knot and Bar-taj Led Godwit, and possibLy other species aLso, may not uncommonLymove between Cefn Sidan and the Burry InLet. More detai Led observat'ions, possibLy incLuding trapping and coLour marking, are required to reveaL the scaLe and frequency of this interchange. ShouLdinterchange prove considerabLe, considenation wouLdhave to be given to Link'ing both the current CarmarthenBay site and Burry InLet as a singLe "CarmarthenBay compLex,,.
33
7. ACKNOI^'LE DGMENTS tJe are indebted to aLL participants over the years in the Birds of Estuaries Enquiry on Carmarthen Bay, as weLL as to others who have provjded important assistance in the production of thjs report. In particuLar, t.le thank Gavin HaLLand Wyn Parry for carrying out Low tide counts along Cefn Sidan, Jeff Kirby and Ian Morganfor muchgeneraL advice and information, DiLwyn Roberts for providing data from county records and for heLp in reorganizing BoEE counting on the site, ELizabeth Murray for drawing the figures and Dorothy SmaLLwootjKeating for computerizing data and typing the report.
The work of the BT0rs Estuaries Programmeis co-sponsoredby the tsTO, Nature ConservancyCounci L, RoyaL Society for the Protection of Bi rds and the Departmentof the Envircnmentfor Northern IreLand.
34
8. REFEREN CES
Davis, P.E, 1984. Bi rds of the coastL i ne f rom Loughor to Laugharne. CycLostyLedreport, 6 pp. NCC,South [,laLesRegion, WaLesF jeLd Unjt.
Morgan, I.K. no date. Birds of the Carmarthenshirecoast. Carmarthenshi re Bi rd Report 19822 18-23.
Owen,N., Atkinson-lrfiLLes,G.L. & SaLrnon,D.G. 1986. t'liLdfowL 1n Great Bri tai n. Znd ed. Univers i ty Press, Cambridge.
Pirot, J.-Y., Laursen, K., Madsen,J. & MonvaL, J.-Y. 1989. PopuLatjon estimates of swans, geese, ducks and Eurasian Coot FuLica atra in the ['lestern PaLearctic and SaheLianAf rica. IIIRBSpec.PubL.re
Prater, A.J . 1977. The bi rds of the tsurry InLet, pp 5 (1)1-5 (1)12 in NeLson-Smith,A. & Bridges, E.M. (eds): ProbLemsof a smaLl.estuary. University CoLLegeof Swansea,Swansea.
Prater, A.J. 1981. Estuary bi rds of Britain and IreLand. Poyser, CaLton.
Prater, A.J, & Rowe, S. 1978. BTO/RSPB/WTBi rds of Estuaries Enquir"y 1969-75: tabLes of average wqde
Prys-Jones, R.P. 1989. The abundance and distribution of wiLdfowL and waders on the CLeddau (M j Lford Haven). BT0 Research Report no.45 and trtCC Chief Scientist Djrectorate commissionedreseanch report no.964.
Prys-Jones, R.P., HoweLL s, R.J. & Ki rby, J . S. 1989. The abundance and distribution of wi Ldfowl and waders on the Burry I Report no.43 ard :'lcc chief scientist Directorate commissionedresearch report no.926.
RamsarConvention Bureau 1988. Convention on wetLands of i nternat i onaL i mportance especi a LLy as waten fow L habitat. Proc .3 rd Mtg.Conf. Cont r. Part i es, Regina, Canada,1987. GLand.
RatcLiffe, D.A. (ed) 1977. A nature conservation revi ew. Universi ty Press, Cambridge.
Roberts, D.H.V. & Morgan, I.K. (eds) no date. Birds in Carmarthenshine: 1984-85. CarmarthenshifeBird Report 1984 and 1985: 1-35 .
SaLmon,D.G.2 Prys-Jones, R.P. & Kirby, J.S. 1988. |'JiLdfowL and wader counts 1987-88. The t,i LdfowLTrust, SLimbridge.
SaLmon,D.G., Prys-Jones, R,P. & Kirby, J.S. 1989. t'liLdfowL and wader counts 1988-89. The WiLdfowL& ['letLandsTrust, SLimbridge.
Smit, C.J. & Pi ersma, T. 1989. Numbers, mjdwinter di st ri buti on, and migrat i on of wader popuLations using the East AtIantic fLyway. It,RB Spec,PubL,9: 24-63. 35
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Appendix 9.3 Scientific namesof species mentioned in the text.
Mute Swan CygnusoLor I Bewick s Swan Cygnusco Lumbi anus bewicki i WhooperSwan Cygnuscygnus Europeantrhite-f ronted Goose Anser a Lbifrons a Lbifrons GreyLagGoose Anser anser CanadaGoose BranTa canadensis BarnacLe Goose Branta Leucopsis Dark-beL Li ed Brent Goose Branta berni c La berni c La SheLduck Tadorna tadorna - hligeon Anas peneLope GadwaLL Anas st repera TeaL Anas crecca MaLLard F?TF-[Filrhynchos Pintai L Anas acuta ShoveLe r niEffiata Pocha rd Aythya ferina Scaup Aythya mari La Eider Somateria moLLissima Long-tai Led Duck CommonScoter MeLani tta ni gra GoLdeneye @ta Red-breastedMerganser Mergusserrator Goosander Mergusmerganser
0ystercat cher Haematopusostra Legus Avocet Recurvirostra avosetta Ringed PLover GoLdenPLover Grey PLover Lapwi ng Knot CaLidris canutus SanderL i ng CaLidris aLba CurLewSandpiper ffiginea PurpLe Sandpiper CaLidris maritima DunLin ffi Ruff Phj Lomachuspugnax Jack Snipe Lymnocryptesminjmus Snipe G?LLinagogaLLinago BLack-tai Led Godwit Limosa Limosa -. Bar-tai Led Godwit LlmOSaLappont ca l,lhi mbre L Numenius phaeopus CurLew Numeniusarquata - Spotted Redshank I r'tnga e ryt hropu s Redshank Tri nga totanus Greens han k Tringa nebuLaria Green Sandpiper Tri nga ochropus CommonSandpiper Acti ti s hypoLeucos Turns tone Arenaria i nterpres 38
Append'ix 9.4 Average monthLy BoEEcounts in winter (November-March)for the period November1982 to November1987 on the Taf and Tywi/Gwendraeth.
Taf Tywi/Gwendraeth
Nov Dec Jan Feb Mar Nov Dec Jan Feb Mar
No.of counts 5 4 3 2 1 1
Mute Swan 00000 1 10 00 WhooperSwan 10000 0 00 00 GreyLagGoose 06100 0 00 00 Brent Goose 10000 0 00 12 SheLduck 60 29 38 98 153 6 8 111 236 389 ['ligeon 14 25 160 94 13 0 s0 200 4?6 TeaL 21018 13 045 90 15 MaLLard 109 177 138 48 10 87 58 14 234 66 Pintai L 103120 0 01 04 ShoveLe r 00000 0 03 00 Pocha rd 00000 0 00 07 CommonScoter 00141 1 00 00 GoLdeneye 00000 1 10 01 Red-br.Merganser 87123 11 ?? 11 16 18
Oystercatcher 336 348 350 673 432 1,840 21713 870 11692 11149 Ri nged PLove r 31 5 132 6 18 11 s4 6 16 GoLdenPLover 269 1,250 75 198 35 42 550 0071 Grey PLover 12 711 0 549 25?28 Lapwing 425 2s5 391 3s 0 370 1,264 57 3?8 143 Knot 20 00 0 136 0 100 SanderL i ng 00 01 0 700 003 DunLin 112 97 60 301 11 335 1,668 1,177 1,249 366 Ruff 00 00 0 10 000 Jack Snipe 00 00 0 01 000 Snipe 13 14 2 0 021 10 42 9 BLack-t.Godwit 00 31 0 00 400 Bar-t . Godwit 97 40 0 ?6 51 101 525 16 CurLew 95 118 63 333 108 158 357 215 414 200 Spotted Redshank 00 00 0 13 000 Redshank 252 147 119 1s2 251 254 275 158 441 294 Greenshank 00 00 0 14 254 Green Sandpiper 00 00 0 22 144 CommonSandpiper 00 00 0 10 000 Turnstone 00 00 0 13 48 61639 39
Appendix 9.5 MonthLy average counts f or the Taf and the Tyw'i/Gwendraeth f rom the spec'iaL studi es carri ed out betweenNovember 1g8Z and February 1988.
Taf Tywi/Gwendraeth
Nov Dec Jan Feb Nov Dec Jan Feb
SheLduck 31 77 109 158 11 42 44 130 Wigeon 0 00 0 13 1 144 TeaL 3 s80 0 62 120 223 MaLtard 153 448 227 107 48 35 236 GoLdeneye 0 00 1 00 00 Red-br.Merganser 0 41 1 61 41
Oystercatcher 760 966 910 698 1 1489 l rgog 1,649 897 Ringed PLover 05 1 1 6 15 12 3 Grey PLover 00 0 0 245 3 Lapwi ng 85 16 472 44s 289 1 668 825 SanderLing 00 0 0 001 0 DunLin 740 14 9 348 456 340 239 Snipe 00 1 0 000 0 BLac k-t . Godwit 00 0 0 13 19 17 15 Bar-t . Godwi t 00 0 0 26 15 72 164 CurLew 68 49 202 195 139 136 197 201 Spotted Redshank 00 0 0 000 0 Redshank 290 292 370 239 250 145 199 149 Greenshan k 00 1 1 210 0 Green Sandpiper 00 0 1 000 0 CommonSandpiper 00 1 0 000 0 Turn st one 00 0 0 9 18 11 19 40
Appendix 9.6 MonthLy peak counts for the Taf and the Tywi/Gwendraeth from the speciaL studies carried out between November1987 and February 1988.
Taf Tywi/Gwendraeth
Nov Dec J an Feb Nov Dec J an Feb
ij SheLduck 67 106 126 200 25 71 48 144 [,Jigeon 0 00 0 100 2 670 TeaL 8 119 0 0 180 238 11 68 MaLLard 388 599 341 199 165 87 51 6 Goldeneye 0 00 2 00 00 Red-br.Merganser 0 10 2 2 74 73
Oystercatcher 1 1528 1,610 1,324 797 1,800 2r57 4 2,2Og 1,0gg Ringed Plover 2 124 6 31 31 25 13 Grey PLover 0 00 1 91?1711 Lapwing 500 80 900 500 310 4 1,000 1,100 Sanderling 0 00 0 0080 Dunlin 22 70 43 35 1,000 780 740 320 Snipe 0 11 1 2000 BLack-t .Godwi t 0 00 0 35 38 27 ?8 Bar-t.Godwit 0 00 0 46 30 168 180 Curlew 93 89 ?70 s22 221 145 324 183 Spotted Redshank 0 10 0 0000 Redshank 510 367 457 297 402 128 225 145 Greenshank 1 11 1 4311 Green Sandpiper 0 00 z 0000 CommonSandp'ipe r 0 11 1 0000 Turnstone 0 00 0 40 55 27 70 41
Appendix 9.7 MonthLy counts for Cefn Sidan from the speciaL studies carried out between November1987 and March 1988.
Nov Dec Jan Feb Mar
MaLLard 0 0 0230 Red-br. Merganser 4 0 0176
Oystercatcher 888 838 651 11900 1,206 Grey PLover 20 1 2001? Knot 0 293 435 600 0 SanderL i ng 423 361 19 675 472 DunLin 170 517 1,295 1,030 13 Bar-tai Led Godwit 1 612 800 CurLew 4 0 040