Lucy'sWarbler Bandingin Southeastern
Arizona
Donald
W. Latnm
6722 E. NasumptaDrive
Tucson, AZ 85715
comm.).
L ucy's
Warbler
(Verrnivora
luciae)
isacommon
summer resident in southern Arizona, southwest New
The datashowfourinstancesof light bodymolt prior to
Mexicoandadjacent
areasofneighboring
states
including
Sonora,Mexico (AOU 1983). In Arizona, it breeds
mainlyin mesquite-cottonwood
associations
of riparian
corridors,mostcommonlyin theLowerSonoranlife zone
andlesscommonlyin theUpperSonoranlife zone(Phillips
et ai. 1964). Duringthetenyearperiod1979-1988,352
mid-July,all in adultbirds.Thisearlymoltcouldhave
beenaconsequence
of nestfailure.Duringthelatterhalf
of July,abouthalf of the adultscapturedshowedbody
moltplusmoltofprimaries
3-6. However,
themajority
of
Lucy'sWarblersleft TanqucVerdeduringthisperiod.
Thereareonly fourcapturerecordsfor August,oneof
were bandedand 59 were recapturedat Tanque Verde
Guest Ranch in Tucson. (See Walters et al. 1984 for
description
of thestudysiteandbanding
program.)
Additionalbandingdatafor theregionwereprovidedby S.
M. Russellwho bandedLucy'sWarblersat sevenlocalitiesin ArizonaandSonoraduringthe years1967-1975.
This paperanalyzesseasonaloccurrence,
timingof molt
and sex identification, and commentson an apparent
populationdeclineatthesitein thelaterhalfof thestudy.
Lucy's Warblers arrive in southcastcmArizona in the
second and third weeks of March (Davis and Russell
1990). The earliestonewasbandedat TanqueVerdeon
13 March
1980.
It was a male with a 4 mm cloacal
protuberance.Youngat onenestfledgedon 13 April; the
earliesta juvenile was nettedwas on 17 May. Lucy's
WarblersbegintodispersefromtheTanqueVerdeareaby
mid-July.I believethattheveryfew birdstakenafterthe
endof July are transientsratherthanlocalbreeders;none
wasa retrap. Apparentlya similarsituationexistsalong
the ColoradoRiver (R. Ohmart, pers.comm.). Lucy's
Warblers continue to be found elsewhere in southeastern
Arizonain Augustbut in considerably
diminishednumbers. Few are recordedin Septemberand the speciesis
unusualin October (Davis andRussell 1990; G. Mortson,
pets. comm.). It is not known whetherbirds that leave
theirbreedingareatendto congregate
in favorablelocations nearby or if most move directly southand are
replacedby migrants.S. M. Russell(pers.comm.)has
seenflocksof up to a dozenforagingon a profusion
of
insectsin a tree. Thelatest,a birdwasbandedat Tanquc
Verde was 2 October 1986. To date, there have been no
whichwasanadultandanotherprobably
so.Bothof these
presumed
adults
weremolting
primaries
andrcctrices,
and
onealsoshowed
heavybodymolt. Of sevencaptured
in
September,
fourweremoltingandthreewerenot, the
latterallcaptured
in thesecond
halfof themonth.Thetwo
Octobercaptures
werenotmolting.Thesedataindicate
thattheprincipal
periodof moltis frommid-Julythrough
mid-September,
andthatmostindividuals
disperse
while
still molting.
Birdswith a cloacalprotuberance
of at least4 mm were
considered
malesandhadwingmeasurements
of 50-59
mm(x=55.23,SD=1.83,n= 126). Fcmaicswereidentified
by thepresence
of a broodpatchandhadwingmeasurementsof 48-59 mm (x=52.06, SD=1.5, n=33). Pyl½et al.
(1987)indicatefemaleshavewings49-56 mm, virtually
identicalwithmy findings,butreportmalesas55-61mm.
I found 18 males below 54 mm and concludethat wing
measurement is not a reliable indicator of sex. Data were
not takenon the extentandintensityof the rufouscrown
patch,suggested
by Pylectal. (1987)asa usefulsexing
characteristic.
Of the59 recaptures,
16werein yearssubsequent
to their
banding,mostof theseeitheroneor two yearslater. Bird
number1950-35395was bandedat TanqucVerde as an
adulton28 May 1981andwasretakenfourtimes,thelast
on 2 May 1985whenit wasat leastfive yearsold. Of the
16subsequent
yearrecaptures,
onlyonewasof a birdthat
had been banded as immature.
For unknownreasonsthenumbercapturedin 1984-1988
recoveries
(D. Bystrak,Bird BandingLaboratory,pcrs.
Jan.- Mar. 1991
NorthAmericanBirdBander
Page9
was <50% of the 1979-1983captures.This declineis
puzzlingas therehas beenno apparentenvironmental
changeduringthe periodnor hastherebeenany major
modificationof bandingeffort. Duringthclatterpartof
the 10-yearpetiod, webworms(Malacosmaincurrum)
werecompletelyeliminatedfromtheareabutthatmaybe
LITERATURE
CITED
AmericanOmithologists'
Union.1983.Check-list
ofNorth
AmericanBirds. 6th edition. Washington,DC.
Davis, W.A. and S.M. Russell. 1990. Birds in Southeast
an unrelated event. It was noted that the number of Brown-
em Arizona.
headedCowbirds(Molothrusater) showeda verysimilar
pattern,peakingwith 52 bandedin 1983 but declining
Society,Tucson.
thereafter to 22 in 1985 and 12 in 1987.
3rd edition. Tucson Audubon
Phillips,
A.R.,J.T.Marshall
andG. Monson.
1964.The
Birdsof Arizona. Universityof Arizona Press,
ACKNOWLEDGMENTS
Tucson.
C. E. CorchranandP.M. Waltersareresponsible
for the
bandingdata from TanqueVerde GuestRanch. Thanks
Pyle,P., S.N.G.Howell,R.P.Yunick,andD.F. DeSante.
1987. Identification Guide to North American
are also due to their assistants and to R. Coates, who
Passerines. Slate Creek Press, Bolinas, CA.
grantedpermission
to bandthere.S. M. Russellprovided
variousinformation,M. Gieselcrperformedthecalculations,C. J. Ralph and S. O. Williams III made helpful
commenBand R. andJ. Tweit providededitorialassis-
Walters, P.M., D.W. Lamm, and C.E. Corchran. 1984.
Twelveyearsof banding
atTanqueVerdeRanch,
Tucson, Arizona. North American Bird Bander
9(4): 2-10.
tance.
Table
1. [Lucy's
Warblers
Captured
atTanque
Verde
Ranch,
Tucson,
AZ
1979-1988
March
April
Year Band Recp
B
R
1979
4
4
1980
I
1
1981
I
3
B
2
June
R
B
July
R
B
2
20
4
5
5
2
20
1
21
2
21
3
18
I
5
3
1
6
I
26
7
I
3
3
4
45
2
6
129
15
48
12
1
1
B
R
2
September
B
R
October
TOTAL
B
B
R
1
II
2
I
49
5
48
6
48
9
59
6
246
34
22
3
15
7
19
3
14
8
45
1984
3
I
t
I
5
1985
3
2
8
3
3
1
1986
I
I
I
I
14
I
2
1987
3
6
2
5
1
2
16
3
1988
I
9
I
18
8
3
31
9
29
7
52
12
8
103
25
Page 1{•
1
9
4
3
8
I
1
I
42
6
3
2
R
TOT
TOT
8
August
R
9
1982
1983
May
I
1
I
NorthAmerican
BirdBander
1
I
Vol. 16, No. 1