CONSERVATION
young/adultratioandtheirdispersalpatternsin given
ISSU ES
habitats, and will be invaluableto understandthe life
historiesof the birdspecies.
This projectis consideredto be one of the strongest
endeavoursin the countryto determinethe trends in bird
migration,
to identifyconservation
issuesand problems
and identifypossibleactionplans.
Table 3. Longevityrecordsof waders.
Species
Years
Crab Plover
Months
9
2
Grey Plover
8
11
Bar-tailed
8
6
Godwit
Kentish Plover
9
0
LesserSandplover
Large Sandplover
20
10
3
0
Redshank
12
2
6
2
MarshSandpiper
Greenshank
11
0
WoodSandpiper
12
4
Red-necked
Little Stint
10
10
5
6
Stint
CurlewSandpiper
11
0
Broad-billed
Sandpiper
10
2
The majorachievementof the projecthas been the
highlighting
of the importanceof certainkey wetlandsand
forest areas in the subcontinent.
This has resulted in a
better understandingof the ecologyof these habitatsand
therebygreater protectionof the areas.
The Great VedaranyamSwamp (now recognisedas a
Ramsar site), PulicatLake and Khabertal(also both
Ramsar sites), Dihaila Jheel (a newly discoverednonbreedingsite of the endangeredSiberianCrane), Chari
Dhandadjoiningthe Great Rann of Kachchhand Gulf of
Mannat Marine National Park on the southeastcoast, are
some of the key wetlandswhich receivedattentiondue to
projectactivities.The respectivestate governmentshave
now includedthese sites in theirfutureactionplans.
Relative masses of primary feathers in waders
L.G. Underhill & R.W. Summers
Underhill,L.G. & Summers,R.W. 1993. Relativemassesof primaryfeathersin waders.
WaderStudyGroupBull.71: 29-31.
L.G. Underhill,
A vianDemographyUnit,Departmentof StatisticalSciences,Universityof Cape
Town,Rondebosch,7700 SouthAfrica,and Schweizerische
Vogelwarte,CH-6204 Sempach,
Switzerland.
R.W. Summers, Lismore,Mill Crescent, North Kessock, Inverness, IV1 1XY, Scotland, UK.
Summers et al. (1983) showedthat moultscoresof
retrappedRedshanksTringatotanustendedto increase
more slowlytowardsthe end of primarymountthan near
the beginning.Thiswas partlybecausethe outer
primariesare longerand heavierthan the innerprimaries.
Therefore,by convertingmoultscoresto percentage
feathermassgrown(PFMG)onecan makethe patternof
increasewithtime more linear(Summers1980). A "moult
index"that increaseslinearlywith time is one of the
underpinning
assumptions
of the moultmodelof Underhill
& Zucchini(1988), and PFMG is undoubtedlymoreclosely
linear with time than the traditional moult score.
In order
to computePFMG, the relativemassesof the primary
feathersfor the speciesunderconsiderationneedto be
known.
One of the purposesof this note is to pointoutthat, for
those wader speciesfor whichthe relativemassesof the
primariesare known,there is sufficiently
littlevariationto
suggestthat a set of average values mightsufficefor all
(or at least most)wader species. The otherpurposeof
this note is to suggesta standardprocedurefor
determiningthe relativemassesand for computingPFMG.
Improvedstandardisation
of methodswillfacilitate
comparisonsbetweenspeciesand betweenareas in the
timing and durationof moult.
To date,the relativemassesof the primarieshavebeen
determinedfor 13 wader species(Table 1). Forthese
speciesand each primary,the maximumdifference
betweenthe average relativemassesand the relative
massesfor the individualspecieswas 1.3%. The
consistentdifferenceswere for Grey PloverPluvialis
squatarola,whichappearsto have relativelylighterinner
and heavierouterprimariesthan average, and Redshank
for whichthe oppositepatternoccurs(Table 1).
The recommended
procedurefor findingrelativemasses
was describedby Summerset al. (1980), and is repeated
here,withsomerefinements.Primaryfeathersin good
condition(i.e. showinglittlefeatherwear and with no
broken-offtips)are needed. The basesof the feathers
29
mustbe clean and undamaged. If they meet the criteria,
the feathers from both wings shouldbe used. The
feathers are labelled, dried to constant mass in a
convection
oven(24-48hoursat 60øC),andthenweighed
as rapidlyas possible. Forwaders, 1 mg accuracyis
adequate. The feathersstart reabsorbingmoistureas
soon as they cool off;this can be checkedfor by
reweighingthe firstfew feathersafter the lastfeather has
been weighed.
To determinethe relativemassesof each primaryfor a
singlebird,add togetherthe massesof corresponding
pairsof primaries(assumingbothwingswere used),and
divideby the totalmassof all 20 primariesfor that bird. If
genera not representedin Table 1, and for charadriids,
bothmigrantand resident.We wouldbe gratefulto
receiveair-driedfreshwingsfromany wader (including
thosein Table 1), witha sampleof no morethanfivepairs
of wings. Thus,in future,we wouldbe ableto updateour
knowledgeof relativemassesof primaries.
Relativeprimarymassesfor five non-wadersare givenin
Underhilleta/. (1991, Table 17), and all are differentfrom
each otherand fromthe valuesgivenfor wadersin Table
1, which should therefore not be used for other families.
ACKNOWLE
DG EM ENTS
data from several birds are available, the means (and
standarddeviations)of the relativemassesof each
primaryfor each birdare computed.Other orderingsof
the steps in doingthe calculationsare possible,and most
will lead to identicalor nearlyidenticalresults. The key
pointis thatthe samplesize shouldbe the numberof
birds,notthe numberof wings. Fromprevious
experience,the standarddeviationsshouldbe small,and
the coefficientsof variationcan be expectedto be less
than about 2%.
LGU acknowledges
supportfromthe University
of Cape
Town Research
Committee
and from the Foundation for
ResearchDevelopment,Pretoria. Unpublisheddata was
providedby the WesternCape WaderStudyGroup
(WCWSG) and J.S. Marks,who, alongwith R.P. PrysJones, commented on an earlier draft.
REFERENCES
To transformthe primarymoultscorefor a waclerwith
moultrecordedaccordingto the systemof Ginn & Melville
(1983)as s1s2s3s4s5s6s7s8s9s
10 (e.g.5554310000)
into
PFMG, the formulaof Underhill& Zucchini(1988) is
recommended:
Ginn, H.B. & Melville, D.S. 1983. Moultin birds. BTO Guide 19.
Tring:BritishTrustforOrnithology.
Kania,W. 1990. The primarymoultof breedingDunlinsCalidris
alpinain the centralTaimyrin 1989. WaderStudy GroupBull.
60: 17-19.
10
PFMG= ,?_.,
mip(si)
wheremiisthe relativemassofthe ith primary,andp(si)
isthemassofa featherwitha moultscores/relative
to its
masswhenit isfullygrown.Thevaluesform/maybe
takenfromTable1, andthoseforp(si)(assumed
to bethe
samefor each primary)fromTable 2. The examplein
Table 3 showsthat a primarymoultscoreof 5554310000
transformsto a PFMG of 28.1%, indicatingthat the bird
has grown28% of the primaryfeathermass(whereasthe
traditionalmoultscoreformedby summingthe scoresfor
the individualfeatherssuggeststhat the bird has
completed23/50=46%of itsprimarymoult). If the wader
hadbeena Grey PloverPluvialissquatarola,
andthe
"correct"relativemassesfor thisspecieshadbeen used
insteadof the averagevalues,the PFMG wouldhave been
Marks,J.S. in prep. Moltof Bristle-thighed
Curlewsin the
NorthwesternHawaiianIslands. [Submittedto Auk in
September1992.]
Summers,R.W. 1980. On the rateof changeof moultscoresin
waders. WaderStudyGroupBull.28: 24.
Summers, R.W., Swann, R.L. & Nicoll, M. 1983. The effects of
methodson estimatesof primarymoultdurationin the
RedshankTdngatotanus.BirdStudy30:149-156.
Summers,R.W., Underhill,L.G., Clinning,C.F. & Nicoll,M 1989.
Populations,biometricsand moultof the TurnstoneArenaria
interpres.withspecialreferenceto the Siberianpopulation.
Ardea 77: 145-168.
Underhill,L.G., Oatley, T.B. & Harrison,J.A. 1991. The role of
large-scaledata collectionprojectsin the studyof southern
African birds. Ostrich 62: 124-148.
Underhill,L.G. & Zucchini,W. 1988. A modelfor avianprimary
moult.
calculatedat 24.7%, and, if a Redshank, as 31.1%. These
discrepancies
representvirtuallythe worstcase deviations
amongstthe 13 speciesconsidered,but will notintroduce
seriousbiasesin the estimatesof the moultparameters
by
the methodof Underhill& Zucchini(1988).
Of the 13 specieslistedin Table 1, 12 representfive of the
generawithinthe Scolopacidae,
but all are migrants.Only
one ploverCharadriidaeis includedin Table 1. Therefore,
thecurrentandprovisional
guideline
isthatformigrant
scolopacids
andpossibly
charadriids,
the averagerelative
primarymassesfromTable1 maybe usedto compute
PFMG. Furtherinformation
is requiredfor otherwader
families,butalsofor"resident"
scolopacids,
suchas the
AfricanSnipeGallinago
nigripennis,
forscolopacids
from
3O
Ibis 130: 358-372.