Raptor round up

40 Pages·1995·2.6 MB·English

by  Scottish Raptor Study Groups

1998 and 1999
i2t'^^[
s(i^D RAPTOR ROUND UP
Produced by the
Scottish Ornithologists' Club
on behalf of all
Scottish Raptor Study Groups
with grant aid from
Scottish Natural Heritage
SRSG
SCOTTISH
NATURAL
HERITAGE
SupplementtoScottishBirdsVolume22 2001
ISSN 00369144
Introduction
This2yeareditionoftheRaptorRoundUphashadalongandsometimespainfulgestation,bedevilled
byawholeseriesofdelaysandproblems. Thesehavefinallybeenovercomeandthisreport-for 1998
and 1999-isthefinalresult.
DuringthisperiodbirdsofpreycontinuedtooccupythepoliticalstageinScotland. Avigorousandnot
always well informeddebate inthe general and specialisedpressrumbledon, focussingonthe inter-
relatedissuesofillegalraptorpersecutionandlegalisedraptorculling.
Againstthisbackgroundbirdsofpreygenerallydidwellbutmarkedexceptionstothistrendpersisted.
Hen Harriers, as ever, heldthe dubious distinction ofbeing Scotland's mostpersecutedbird. Golden
Eagles stillhad 'holes' in theirbreeding distribution with noobviousecologicalexplanationforsuch
gaps. SomeNorthernGoshawkpopulationsdidnotexpandedaswellasothers-thedifferencesalmost
certainlyattributabletopersecution. RedKites-inallotherrespectsagreatsuccessstory-experienced
levelsofpoisoningthatmayrestricttheirrateofexpansion. Notallpoorperformancewaspersecution
related. FarnorthernandwesternPeregrineFalconsshowedlowlevelsofsiteoccupancyinsomeareas.
Orkney Hen Harriers - free of human interference - continued to decline, a situation that is being
examinedinadedicatedresearchprogramme. However,therewascontinuinggoodnewsforCommon
Buzzards, OspreysandWhite-tailedEaglesandnotallpopulationsofthepersecutedspecies suffered
fromthischronicproblem.
ThefutureoftheRaptorRoundUpitselfisnowinsomedoubt. SomeRSGworkershaveexpressedthe
viewthatthenewSNH/BTOraptormonitoringproposalswillautomaticallymeantheendoftheRound
Up. Othershavesaidthatthe2thingsarenotmutuallyexclusiveandshouldcontinueinparallel. Ioffer
noviewofmyownonthisissueexcepttosaythatitshouldberesolvedbyacollectivedecisionofthe
Groups. A2000RaptorRoundUpalreadyexists inembryonicform.
KeithMorton
Thisreportwaswrittenby Keith MortonwithlayoutandeditinginputfromSylviaLaing,Bob
Dawsonand Helen Cameron. ItisbasedonmaterialsuppliedbyScottish RaptorStudyGroup
members. The Scottish RaptorStudy Group logowasdesigned anddrawn by Keith Brockie.
1998 & 1999RaptorRound Up 1
Red Kite Milvus milvus
Central Scotland
occupied successful chicks fledged
1998 2 2 5
1999 6 4 5
1998-Afirstyearmalewasestablishedonanother 1999 - A seventh potential pair of birds spent
territory. Territoryoccupation/breedingprogress some days together over an ill defined area that
is2yearsaheadofthatofthenorthernrelease. A may prove to be afuture territory. Asixth chick
Red Kite was found poisoned some distance to hatchedbutfelloutofthenestandwaspredated.
the north ofthe release area in March. Twenty Allyoungwerewingtagged. Onebirdwasfound
furthernewbirdswereintroducedfromGermany. poisoned close to the eastern edge ofthe release
area and a number of other poisonings in this
immediate areagave cause forconcern. Twenty
furthernewbirdswereintroducedfromGermany.
Highland
checked occupied laid hatched successful chicks fledged
1998 38 28 23 21 20 44
1999 48 32 30 22 54
1998-Inadditiontothe28territoriesoccupiedby This is the first record ofa North Scotland kite
pairs,4territoriesheldsingleadults.Thenumbers breeding away fromthe core area.
ofpairs laying eggs showed no increase on the
FourRed Kites were found deadduring 1998 in
previous year. This is thought to be due to a Highland. Three of these were poisoned. No
combination of poor spring weather deterring
causeofdeathwasfoundforthefourth,atideline
new pairs from nesting and low recruitment of
corpse nearNorth Kessock.
new breeding pairs. However, in terms of the
number of pairs rearing broods and the total A 1997 Black Isle chick was seen in south east
number of young fledged, 1998 was the most Icelandfrom 15 December 1997 and throughout
successful breeding season experienced so far. 1998. This remarkable sighting (1,017km north
Forty one of the 44 young reared were marked west)constitutesthefirsteverrecordofaRedKite
(brightbluetagontheleftwing-regionalcolour in Iceland. There were more normal winter
code - lime green tag on the right wing - year sightings of Highland tagged birds from Tiree,
colour code - with a unique inscription - single Tayside,KyleofLochalshandStrathspey. Further
whiteletter,whitenumberorredsymbol-onboth afieldwere2 birds in Ireland (Co. ClareandCo.
tags). A male Black Isle chick from 1996 was Cork) and a singlebird at Rhayaderin Wales.
located at a kite roost in Central region in the
companyoflocallyreleasedbirds. Hepairedwith
a2yearoldlocalandsuccessfullyreared2young.
1
2 1998 & 1999RaptorRound Up
1999 - In terms of the number of pairs rearing Thebreedingresultswouldhavebeenevenhigher
broods and the total number of young fledged, but for the miserably cold weather experienced
1999 was the most successful breeding season during mid May and early June which caused
experienced so far. There was a 30% increase in several inexperienced pairs to fail. A bird from
thenumberofyoungrearedcomparedto 1998. It North Scotland area was recovered dead under
hasbeen suggestedthatthere shouldbeagreater power lines nearBilbao, Spain in May.
numberofpairsthanactuallyexistsatthepresent
inNorthScotland. Lowrecruitmentin 1997may
be toblame forthis.
1
AngusHogg
White-tailed Eagle Haliaeetus albicilla
occupied laid successful chicks fledged
1998 17 15 9 13
\999 18 15/16 6 11
10Year Summary
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999
Noofpairs ortrios 9 9 8 8 10 10 12 13-15 18-18 15-16
Noofareas occupied 12 10 10 10 1 14 14 14 18 20
Noofclutches laid 9 8 9 6 8 9 12 11-13 16-17 15-16
Noofclutches known 2 4 4 4 4 6 8 6 9 9
tohavehatched
No ofbroods fledging 2 4 4 4 4 5 7 5 9 6
Young
No ofyoung fledged 2 7 7 5 5 7 9 9 13 11
Cumulativenoof 4 4 5 5 5 6 8 9 12 12
territories producing
young
1998 & 1999RaptorRound Up 3
Thesecondphaseofthereleaseprogrammebegun 1999 was the second most successful year since
in 1993wasconcludedin 1998withtheimportof thereintroductionprojectbegan24yearsago. A
thefinalbatchofchicksfromNorway. Between total of 11 young fledged from Scottish nests, 2
1993 and 1998 atotal of59birds werereleased. lessthanin 1998.Allnestfailureswereattributed
to natural causes, although disturbance was
In 1998&99successfulpairsfledgedatotalof13 suspected at one site. One pair failed when an
chicks. Thisincludedthefirstbirdstobreedfrom apparentlyhealthy3weekoldchickfelloutofthe
the second phase release - 2 pairs - and a new nest. Oneofthebirdsreleasedin 1998wasfound
Scottish bred pair which had failed in 1997. dead(ofnaturalcauses)inSutherland. Ofthe59
Breedingsuccessfigureswouldhavebeenbetter released in the second phase only 3 have been
butfortheattentionofeggcollectorswhorobbed recovereddead.
2establishedandnormallyproductivepairs. Eggs
stolenatoneofthesesiteswerewithinafewdays The cumulative number of pairs to have
ofhatching. successfullyproducedyoungremainsunchanged
and 12.
4 1998 & 1999RaptorRound Up
Hen Harrier Circus cyaneus
Orkney
breeding breeding nesting laid hatched fledged chicks
females males attempts fledged
1998 46 27 34 26 14 9 20
1999 17 24 21 10 10 21
1998 - This season saw the start ofa PhD study
intoOrkney's Hen Harriers. 1999-IntheWestMainlandstudyarea32females
and20males-ofwhich4werefirstyearmales-
Theresultsfrom 1998showaverysimilarpattern were located. Twelve of the females were non
tothatofrecentyears InOrkneyasawholewhere breeders but ofthe 20 which did attemptto nest
.
46 females and 27 females ofwhich 39 females only 18 laideggs. Tenofthenestsfailedduring
and21 maleswereintheWestMainland, 5 pairs incubationbut8hatchedyoung. Inaddition,one
wereonHoyand2femaleswithonemalewereon ofthefailedfemalessuccessfullyrelaidtogivea
Rousay. The number of males in the West totalof9broods. Fromtheseatotalof20young
Mainland is higher than thought in 1996/97 but fledged,aproductivityof2.2youngpersuccessful
thedifferenceismainlyinthenumberoffirstyear nestof 1.0perbreeding female.
birds(5in 1998). OneoftheHoymaleswasalso
afirstyear. On Hoy, 4 pairs attempted to nest. At one site
nesting material was carried in; it is not known
Twelveofthefemales (11 inthe WestMainland whether eggs were laid but this site did not rear
and one on Rousay) were non breeders but 34 young. Anothersitefailedduringincubationand
females(28WestMainland,5onHoyandoneon anotheratthechickstage. Thefourthnestreared
Rousay) did attempt to nest. Eight ofthe West 2 chicks.
Mainlandfemalesdidnotlaysothesuccessof26
nests with contents was followed. Twelve of OnRousayafemaleandanadultmalewereseen
these(9intheWestMainlandand3onHoy)failed occasionally but no nest was ever found and no
attheegg stage while afurther5 (allintheWest young were reared.
Mainland) failed at the chick stage. There were
thusonly9 successful nests(6WestMainland, 2 TheoverallOrkneytotalswerethus25males (of
Hoy, andone Rousay) whichproducedatotal of which4werefirstyears)and37females(ofwhich
20fledged young (1 1 West Mainland, 5 on Hoy 13 were non breeders). The 24 females which
and4on Rousay). attemptedtobreed laidat least 21 clutches from
which 22 young were reared. The improved
breeding success ofthe birds which bred in the
West Mainland is thought to be due to the
supplementary feeding being carried out as an
experimental partofathe PhD study.
1998 & 1999RaptorRound Up 5
Lothian and Borders Argyll
1998 - Five pairs were seen but only one was 1998 - Selected 10km squares were surveyed in
allowedtobreed and this subsequently failed. ArgyllbyRSGmembersandRSPB fieldstaffas
part ofthe national survey. Fifty two territorial
Lammermuirs - 1 pair seen early which then pairs werelocatedinthese squaresandthe study
disappeared; area. Some ofthese survey squares in Kintyre,
Moorfoots-3pairspossiblypresent,onepredated
Islay and Jura held up to 5 pairs (probable plus
atlarge young stage; possible). Quotingjustthesehigherfigureswould
Pentlands - one territorial pair. obscure the overall picture. Some surveyors
1999 - Ten pairs were known but only 3 pairs foundnoharriersintheirchosensquaresincluding
withintheBordersportionoftheLangholmstudy one square in mid Argyll which supported none
arearaisedany young. forthe first time in 10 years ofstudy. Based on
this data an extrapolated figure of 124 pairs was
Pentlands-onepairandanextrafemalewereseen estimated for Argyll (25% of the extrapolated
inoneareafrommidApriltoearlyMay. Amale Scottish population). The RSPB Loch Gruinart
was seen 2-3km away from this in early May. reservehadagoodyearforHenHarrierswithnine
There were nofurthersightings. territoriesoccupiedand5successfulpairsraising
12 chicks.
Moorfoots - There was apairin one areaApril-
May, seen skydancing but with no evidence of Wherecausesofnestfailurewereidentified,most
nesting. Anextramalewasseenononeoccasion. appeared to be natural including a site that was
Apairatanothersitec4kmawaywasseeninmid predatedbyaFoxonCowal. Howeverthepresence
April andwere skydancing in late May. ofadultfemale feathers atanotherfailedneston
Cowalandtheremainsofadeadadultfemaleata
Lammermuirs - A male was seen at one site in site on Bute are ofmore concern.
April and another displaying at another site in
May. There was anunsubstantiatedreportthata 1999 -samplesitesweremonitoredonMull,Islay
male and 3 females were killed in the (including the RSPB Reserve at Loch Gruinart)
Lammermuirs. MidArgyll, Knapdale, Kintyre,CowalandBute.
AtLochGruinartreserveitwasapoorseasonwith
TweedsmuirHills-amalewasdisplayinginearly only3pairsproducing8young. OnBute,onenest
April and pair at the end ifthe month. Nothing fledged 2 chicks and also contained 2 further
morewasseenon2visitsinmidandlateMay. A chickswhichfailedtodevelopprimariesanddied.
pair were prospecting and male displayed at (Thesesymptomshavebeenseenoncepreviously,
different site but nonest was found. 2 years ago).
Langholm Area (Borders only) - Three pairs
fledged 7 young.
Elsewhere-ApairwaspresentintheNewcasdeton
area (outwith the Langholm study area) with no
evidenceofsuccess. Apairwaspresentsouthof
Hawick.
Andrew Stevenson
6 1998 & 1999RaptorRound Up
occupied laid fledged chicks fledged young per
successful territory
1998 (47-52)t 27* - 18 52 2.88
1999 (27)»24'* 21 16 39+ 2.43
1998 -The survey requiredproofofoccupationbutdidnotrequireneststobe locatedandbreeding successto
be followed up. Thisexplains the discrepancybetweenthe large numbersofoccupiedterritories andthefar
smallerfigures fornests completely monitoredby groupmembers,
t 1998 - Numbers inbrackets are all probableplus all possiblepairs located.
1999 -Numbers in brackets includeallpairs located, including territorialpairspresentin earlyspringbut
whichdidnotstay tobreed.
* 1998 Noofsites fully monitored (included inthenumberofprobable andpossiblepairs) forbreeding
success.
** 1999Noofsites (includedin thetotal) thatwerefullymonitoredforbreedingsuccess.
North East
1998 - The national survey resulted in good 1999- 1999wasaanotherpooryearforharriers.
coverage. Persecution continued to be recorded InlowerDeeside,wheretherewereusually 15or
as the major cause of failure with adults sopairseachyearinthe1970sand80s,therewere
dissappearingfromanumberoflocalpopulations. onlytwopairs. Onewasdefinitelypersecutedand
the otherprobably so.
pairs outcome failed successful chicks
unknown fledged
1998 27 17 18/19+
1999 14 6 19
Central
1998-The partialcoverage ofthe area suggests 1999-There were afew records fromthe south
apoor season. Forone ofthe 3 failed pairs this eastofthegroup'sareaincluding2femalesanda
wasthesecondyearrunningthatthishashappened. male present in spring at one locatidn. In
Onepairmayhavebeensuccessfulbuttheresult Dunbartonshireonepairreared4young,onepaired
was not confirmed. reared3young,onepairfailedandoneadditional
pairwaspresent.
checked failed fledged chicks fledged
1998 4 3 17 ?
1999 5 1 2 7
1998 & 1999RaptorRound Up 7
Tayside
1998-InPerthshirefewerpairswerelocatedthan occupied fledged chicks
previously but mean productivity of successful fledged
pairs washigh. Therewere 17pairsWestofthe
A9 and 25 in the core area East ofthe A9. One 1998
bigamous male was successful withbothbroods Perthshire 42 17 61+
butthere were alotof"spare"birds around. Angus 2 1 2+
Total 44 18 63+
In Angus 2pairs were located, ofwhich one was
successful. Inbothcasesthemaleofthepairwas 1999
afirstsummerbird-indicativeofpersecutionin Perthshire 23 13 37
thearea. Thesuccessfulpairlaid7eggsofwhich Angus 3 2 6
3 hatched. The number ofpairs in Angus is far Total 25 15 43
belowthecarryingcapacity-againindicativeof
persecution.
1999 - In Perthshire coverage was lower in the InAngus2pairssucceeded-thebestperformance
mainstudyareathanin 1998. Earlyfailureswere since monitoring started in 1983 but almost
attributed to heavy rain and productivity was certainlyonlyafractionofthearea'struecarrying
slightlydownonthepreviousyear. Thereappears capacitywithpersecutionthemostlikelycauseof
tobeacontinuedgradualdeclineinthewestofthe this situation.
area.
Dumfries & Gallowayand South
Strathclyde
1998-Overallthiswasarecordyearforbreeding Langholm where the species continues to enjoy
insouthwestScotland,withmorepairsoccupying protection. In addition, the simple occupation
territorythaneverrecordedbefore. Howeverthis figuresmaskahighlevelofpersecutioninmany
number is certainly bolstered by the situation at areas away from Langholm especially in upper
occupied laid successful failed outcome chicks
(human) unknown fledgec
1998
S.Strath. 44 31 13/14 22 (20) 9 46+
D&G
34 27 20 9(5) 5 63+
Total 78 58 1 33/34 31 (25) 14 109+
1999
S.Strath 34 34 7 27(77)+ 1 18
D&G
20 16 10 6(5) 30+
,
Total 54 50 ' 17 33(22) 1 48+
1
8 1998 & 1999RaptorRound Up
NithsdaleandaroundMuirkirkwhereproductivity 1999 - In contrast to the 1998 survey year 1999
is consistently low. wasapooryearfordatacollectionofthisspecies
the Highland area. Only 10 active nests were
1999-PersistentpersecutioninupperNithsdaleis checked,thelowestnumbersince 1987. Thehigh
fastreducingthebreedingpopulation,withonly3 numberofnests monitoredintheperiod 1989 to
breeding attempts in 1999 (all unsuccessful). 1995 correspond with a long term RSPB study
Several years ago some 10 to 12 pairs were involving wing tagging ofyoung. There was a
regularly attemptingtobreedinthisareabutthis briefresurgence inthe numberofnestsrecorded
hasbeengreatly reducedby nestdestruction and in1998,theyearofanationalHenHarrierbreeding
almostcertainlybythekillingofthefemalesatthe survey. The recent reduction in the number of
nest. This subpopulation is likely tobe reduced nestrecords submittedcouldreflecteitheralack
tosporadicbreedingattemptsbyprospectingpairs. of effort by the group or may mirror a general
HeavypersecutionalsoremainsapparentinSouth decline in the numberofbreeding pairs present.
Strathcyde in the Muirkirk area resulting in a There is someevidencetosuggestthelatter. No
mean of only 0.53 chicks produced for each harriers were recorded at 5 traditional breeding
occupiedterritory. sites which did receive repeated visits in the
springof1999. Allwereonactivegrousemoors,
3 in east Inverness and 2 in Badenoch and
Highland
Strathspey. This could suggest that persistent
persecutionisnowhavinganimpactonthenumber
1998 - The late spring and cool wet summer of ofpairs not only on sporting estates but also on
1998resultedinabelowaveragebreedingseason othermoors throughout ourstudy area.
forunpersecutedpairs. Asampleof15nestsgave
ameanclutchsizeof4.8, slightly belowthelong Mostofthe nest records submittedin 1999 were
term average. Brood sizes tended to be on the notondrivengrousemoors,sothatnestingsuccess
smallsizewith4b/2,5 b/3,4b/4andasingleb/5 ofthesample(70%)washigherthanthelongterm
from the sample of23 nests. This gives a mean average (see table below). Mean brood size in
broodsizeof 1.9youngperbreedingpairand3. 1999 at 2.0 young perclutch laid and 2.9 young
perpairrearing young. Nine nests (39%) failed per successful nest was close to the long term
completely. The causes were: unknown (1-2); average.
persecution (5-6); natural predation (2).
laid hatched fledged chicks fledged
1998
Sutherland 7 6 5 13
ERoss 2 2 2 7
Bad & Strath 4
Nairn 1 1 1 4
W
Moray 9 8 6 20
Total 23 17 14 44