J. Field Ornithol., 61(2):171-173
NESTING FISH CROWS ADOPT A FLEDGLING BLUE JAY
KEVIN J. McGOWAN•
Department of Biology
University of South Florida
Tampa, Florida 33620 USA
Abstract.--A fledglingBlue Jay (Cyanocittacristata)appearedin a Fish Crow (Corvus
ossifragus)
nestcontainingyoungnestlings.The jay was fed by both adult crowsfor 12 d
beforeit disappeared,representingonly the secondrecordedinstanceof interspecificfeeding
by a memberof the family Corvidae.The jay probablyenteredthe neston its own after
fledgingfrom a nearbynestand wasnot considered
potentialprey while nearthe crownest.
CORVUS OSSIFRAGUS ADOPTA UN PICH•)N DE CYANOCITTA CRISTATA
Sinopsis.--Un pich6nde Cyanocitta
cristataapareci6en un nidode cuervos(Corvusossifragus)
conteniendo
polluelos.E1 pich6nfue alimentadopor los cuervosduranteun perlodode 12
d, al t6rminodel cual el pich6ndesapareci6.
Estees el segundoregistrode una instanciade
alimentaci6n
interespecifica
porun miembrode la familia Corvidae.E1pich6nde Cyanocitta
cristataprobablemente
entr6 al nido por si solodespu6s
de haberdejadosu propionido,y
no fue considerado
comoposiblepresamientrasestuvoen la vecindaddel nidode loscuervos.
Skutch(1987) reviewedthe literatureon interspecific
feedingin birds,
and reporteda singleinstanceof this phenomenonin the family Corvidae:
a captiveCommonRaven (Corvuscorax)feedinga wild Black Vulture
(Coragyps
atratus)(Davis 1952). I report prolongedcareand feedingof
a fledglingBlue Jay (Cyanocittacristata)by nestingadult Fish Crows
(Corvusossifragus).
At 0905 (EDT) on 22 May 1987, I had been watching a Fish Crow
nest for 20 min as part of a study of the nestingbiologyof Fish Crows
on the campusof the Universityof SouthFlorida, Tampa, Florida. The
nestcontainednestlingsbetween3 and 7 d old and was attendedby two
adults.The femaleof the pair was distinguishable
by the absenceof a
secondary
in her right wing. The male hadjust cometo the nestand fed
nestlingsand was perchedon the rim, peckingin the nest. Suddenlya
fledglingBlue Jay, approximately30 d old, appearedon the nest rim
from insidethe nest bowl. It beggedat the crow, but was ignoredand
remained
on the nest rim.
At 0906
the female
crow arrived
at the nest
and fed nestlings.The male took somefood from the femaleand alsofed
nestlings.The jay beggedbriefly, and was fed by the male. At 0909
the male left and the femalesettledontothe nest.The jay sat on the nest
rim, preenedand stretched,
and occasionally
lookedinto the nest.At 0925
h when the crowwas peckingin the nestand had its bodyraisedslightly,
thejay hoppeddowninto the nestbowl. The crowthensettleddownonto
the nestagain, and remainedthis way until I left at 0930.
I observedthe Blue Jay at the crow nest on five occasions
over 12 d.
I observedthe crows feed the jay eight times: the male five times, the
• Currentaddress:
Section
ofEcologyiv Systematics,
Corson
Hall, CornellUniversity,
Ithaca,New
York 14853-2701
USA.
171
172]
K.J. McGowan
J.Field
Ornithol.
Spring 1990
female three. Never did the adult crows show any signs of aggression
toward the jay. In the first few daysthe jay spentmostof its time in the
nestor on the rim. Later it spentmore time in the nesttree away from
the nest, returning to beg when the crows arrived at the nest with food.
The jay movedfarther from the nest on each observation.Eventually it
may have left the nest tree and no longer was fed by the crows,who
continuedto attendthe nestfor three weeksafter the Blue Jay was last
seen.Blue Jays have a relativelylong period of dependence(80 days,
Laskey 1958), and this jay probablywas incapableof feedingitself and
would
not have survived
unattended.
These observations
presenttwo questions:how did the jay get into the
crow nest, and why was it not eaten by the crows, known to prey on
fledglingbirds (Bent 1946, Taylor 1972)? Several avenuesof entrance
into the nest are possible.The jay could have been brought alive to the
nest,couldhavehatchedin the nestfrom an eggdumpedinto it, or could
have fledgednearby and climbedinto the neston its own. It is unlikely
that the crowsbroughtthe jay into the nest as food,becausethey never
broughtwhole,unprocessed
fooditemsto the nest.Invariably,beforethey
tookfoodto the nestthey perchednearbyand peckedthe itemsinto small
pieces.Piecesof food items were left on theseperches,and often were
revisitedafter the nest visit in a manner similar to the cachingbehavior
reportedby McNair (1985). Interspecific
eggdumpingis unlikelybecause
the jay was approximately30 d old, and the crowswere at most7 d old
on the first observation.With an 18 d incubationperiod for the jay
(Arnold, in Bent 1946), the eggwould have to have beenlaid at the end
of March, when the nest was just under construction.These factsleave
only the possibilitythat the jay climbedinto the nestitself after fiedging
nearby.I did not find any Blue Jay nestsin the vicinity, but Blue Jays
commonlynestedon campus.
Why did the crows not eat the jay? Fish Crows raid Blue Jay nests
and will eat young Blue Jays: I witnesseda pair of Fish Crows raiding
a Blue Jay nest (probablywith eggs)in Hardee County, Florida on 25
May 1988, and I found remainsof old nestlingor young fledglingBlue
Jays beneatha cachesite near a Fish Crow nest in Tampa in May and
June 1988. It is possiblethat the jay arrived at the nestwhile the crows
were absent.Fish Crows appear to prey heavily on nestlingpasserines
during the nestingcycle(pers.obs.) but may have an inhibition against
eatingsmallbirdsin their own nest,therebynoteatingtheir own offspring.
As long as the jay was in or near the crows' nest it might have been
protectedfrom being treated as potential prey. Parental recognitionof
chicksis known to developslowly over the nestingperiod in somebird
species(Burtt 1977 and referencestherein). Yom-Tov (1976) foundthat
Carrion Crows (Corvuscorone)did not distinguishstrangechicksintroducedinto their nestscontainingyoung nestlings,even chicksof Rooks
(Corvusfrugilegus)or Herring Gulls (Larus argentatus).Severalspecies
of Corvusare regular hostsof the Great SpottedCuckoo(Clarnatorglandarius) (Witherby et al. 1965), a brood parasite.Yom-Tov (1976) rea-
Vol.61,No.2
FishCrows
Adopt
BlueJay
[ 173
sonedthat crowsare slow to developchick recognitionbecause,as nest
predators,the dangerof attackingtheir own eggsand young is greater
than the advantageof having a goodantiparasiticdevice.
Intraspecificadoption may occur regularly in somebird speciesfor
reasonsnot fully understood(e.g., gulls [Larussp.] Pierotti 1980; Black
Tits [Parusniger], Tarboton 1981). Interspecificadoptionis relatively
rare, and is heretofore unknown in corvids.
ACKNOWLEDGMENTS
I thank David Winkler, Kimberly Kline, Lawrence Kilham, Edward Burtt, Jr., and an
anonymousrefereefor helpful commentson the manuscript,and RoxannaNormark for the
Spanish abstract.
LITERATURE
CITED
BENT, A. C. 1946. Life historiesof North American jays, crows, and titmice. U.S. Nat.
Mus. Bull., No. 191.
BURTT,E. H., JR. 1977. Somefactorsin the timing of parent-chickrecognitionin swallows.
Anim.
Behav.
25:231-239.
DAVIS,M. 1952. Captive Raven carries food to non-captiveBlack Vulture. Auk 69:201.
LASKEY,A. R. 1958. Blue Jays at Nashville, Tennessee;movements,nesting,age. BirdBanding 29:211-218.
McNAIP,, D. B. 1985. An auxiliary with a mated pair and food-cachingbehaviorin the
Fish Crow.
Wilson
Bull.
97:123-125.
PmP,OTTI, R. 1980. Spite and altruism in gulls. Am. Nat. 115:290-300.
SKUTC•I,A.F. 1987. Helpers at birds' nests.Univ. of Iowa Press,Iowa City.
TAYLOR,W. K. 1972. Mobbing of a Fish Crow by passetines.Wilson Bull. 84:98.
TARBOTON,W. R. 1981. Cooperativebreedingand group territoriality in the Black Tit.
Ostrich
52:216-225.
WITHERBY,H. F., F. C. R. JOURDAIN,N. F. TICEHURST,ANDB. W. TUCKE•t. 1965. The
handbookof British birds. Volume II. H. F. & G. Witherby Ltd., London.
YOM-TOV,Y. 1976. Recognitionof eggsand youngby the Carrion Crow (Corvuscotone).
Behaviour
59:247-251.
Received12 Oct. 1988; accepted9 Sep. 1989.