10. Predatory Attack on Bats by Barn Owl Tyto Alba and Shikra Accipiter Badius in Tamil Nadu State, South India

2 Pages·2001·1.3 MB·

by  G Agoramoorthy

MISCELLANEOUS NOTES
Thenextday,at 1215hrs,theskywasdark the bats to go back to their roosting site.
and overcast. With a camera inhand, I satinthe This observation, and that of Mum and
balcony to observe the behaviour ofthe shikra. Hegde(1998),showsthattheshikraisacommon
The bats started emerging from the dried fronds predator ofshortnosed fruit bats.
of the palmyra palm. At the same time, four
shikras arrived on the scene, one was ajuvenile January 1,1999 ASHFAQAHMEDZARRI
andthe restwere adult. They startedchasing the Centre ofWildlife and Ornithology
bats, but no capture was seen. This went on till Aligarh Muslim University,
1510 hrs. Subsequently, rain once again forced Aligarh 202 002, Uttar Pradesh, India.
PREDATORYATTACKONBATS BYBARN OWL TYTOALBA AND
10.
SHIKRAACCIPITER RADIUSINTAMILNADU STATE, SOUTH INDIA
Evidence ofpredatorshaving a significant gateway of the Vishnu temple at Tirunagiri
effectonbatpopulationsissparse.Fewpredators village, Nagai district. When a temple worker
specialize on bats, but the largely anecdotal climbed on to the gateway, some bats flew into
literature cites many occasional bat-eaters such darker spots in the temple. Just then, one bat
as monkeys, racoons, opossums, cats, raptors, came outside and was immediately captured by
snakes, frogs, spiders and bats themselves a shikra that flew from the top of the temple
(Altringham 1996). Avian predators such as gateway’sexterioranddisappearedintotheforest
owls, hawks andfalcon are knownto attack and with its catch.
feed on bats occasionally (Gillette and Case 2: A colony of 400 greater false
Kimbourgh 1970). Bats are particularly vampire bats Megaderma lyra regularly roosted
vulnerable to aerial predators when they leave in an abandoned house atTirunagiri village. On
their roosts or while feeding at night. India is September6, 1996,at 1830hrs,thefalsevampire
home to about a hundred species ofbats, and at bats emergedfromtheirroost. Onebatwas seen
leastelevenspeciesofavianpredatorshavebeen isolatedfromagroupof20individuals. Suddenly,
observedtopreyonbatsoccasionally inthepast a barn owl flew from the roof of the house,
(Muni and Hegde 1998). Since July 1995, we stooped 4 m downwards and then flew about
m
have been conducting bat surveys in Nagai 10 inpursuitofthebatandcaughtitwhilethe
district, Tamil Nadu, India (Agoramoorthy and bat was in flight. The owl captured the bat with
Hsu 1998).Weobservedthreecasesofpredatory itsbeakandclawssimultaneously,andapparently
attacksonbats,twobyabamowl Tytoalba, and swallowed it in flight. The attack lasted about
onebya shikraAccipiterbadius. Allthreecases 6-7seconds.Thesitewheretheowlrestedearlier
were observed in Tirunagiri village which is was checked, and pellets with skulls and bone
locatednearthetownofSirkaliinNagaidistrict. remnants ofrodents and bats were found.
Thefirstcaseofpredatoryattackbyshikra Case 3: On September 26, 1996, at
was observed during the day near abat roosting 2130 hrs, a male bam owl was seen resting on a
m
site. In the second and third case, the bats were palmyrapalmtreeBorassusflabellifer, about7
attackedby bam owl while they were emerging above the ground at Tirunagiri village.
m
at dusk, and while foraging at night. Approximately 10 awayfromtheowl,about30
Case 1: On August 2, 1995 at 1100 hrs, shortnosedfruitbatsCynopterussphinxwereflying
we studied a colony of250 black-beardedtomb andfeedingonmahuaMadhucaindicafruit.They
m
bats Taphozous melanopogon located in the were about 4 above the ground while feeding.
JOURNAL, BOMBAYNATURAL HISTORYSOCIETY, 98(1),APR. 2001 107
MISCELLANEOUS NOTES
One shortnosed fruit bat moved from the group eat individuals of Rousettus aegyptiacus (Hill
andcameclosetothepalmtreewheretheowlwas and Smith 1984). Although Speakman (1991)
resting. Immediately, the owl swooped and reported that bats made up only a small part of
captured the bat in flight and returned to the tree the diet of owls in Britain, Julian and
where it had been perching. It rested there with Althringham (1994) predicted that individual
the bat for about 10 seconds, got a firm grasp on owls couldtake large numbers ofbats, andmay
the bat with its feet, and flew away. The bat did influence the population size in bat colonies.
notproduce any screams audible to human ears. Onlytwocases ofbamowlpredationhave been
In South Africa, Fenton et al. (1994) observed during our study, and more data are
reported 59 attacks by diurnal raptors on bats neededto evaluate whetherornotowlpredation
and the predators included hobby falcon Falco influences the population size of bats around
subbuteo,AfricangoshawkAccipitertachiroand Tirunagirivillage inNagai district, TamilNadu.
Wahlberg’seagleAquilawahlbergi. Similarlyin
south-eastern Australia, Speakman etal. (1994) February 15, 1999 G.AGORAMOORTHY
releasedbatsduringdaytimetotestthepredation Bat Conservation Project,
rates, and observed 1 1 attacks by diurnal S.M. Govindasamy Nayakkar
predatorybirds. ShortnosedfruitbatsCynopterus Memorial Foundation,
sphinxusuallyproducedshrill screamswhenwe 4 Thittai Road, Thenpaty 609 111,
handled them in mist nets, but the bat attacked Nagai District, Tamil Nadu, India.
bythebamowldidnotscream.However,Fenton MINNA J. HSU
et al. (1994) report that bats taken by raptors Department ofBiological Sciences,
uttered screams clearly audible to human ears. NationalSun Yat-sen University,
Batbones were seen in owl pellets, andAfrican Kaohsiung 80424,
bam owls Tyto alba were reportedto attack and Taiwan, Republic ofChina.
Refer 'nces
Agoramoorthy, G. & M.J. Hsu (1998): Occurrence of UniversityofTexasPress,Austin,USA.
microchiropteraspeciesinNagaiDistrictofTamilNadu Julian,S. &J.D.Altringham(1994): Batpredationbya
State,India.Zoos’Print13(4):3-4. tawnyowl.Naturalist119:49-56.
Altringham, J.D. (1996): Bats. Biologyand Behaviour. Muni, M. & V. Hegde(1998): Indian shikrapreyingon
OxfordUniversityPress,Oxford. shortnosedfruitbats.J.Bombaynat.Hist.Soc. 95(2):
Fenton, M.B., I.L. Rautenbach, S.E. Smith, C.M. 338-339.
Swanepoel,J.Grosell&J.Van(1994):Raptorsand Speakman,J.R.(1991):Theimpactofpredationbybirds
bats:threatsandopportunities.Anim.Behav.48:9-18. onbatpopulationsintheBritish Isles.MammalRev.
Gillette, D.D. & J.D. Kimbourgh (1970): Chiropteran 21: 132-142.
mortality.In:Aboutbats.Eds.Slaughter,B.H.andD.W. Speakman, J.R., L.F. Lumsden & G.C. Hays (1994):
Waiton.Dallas,SouthernMethodistUniversityPress, Predation rates on bats released to fly during day-
Dallas,pp.262-281. light in southeast Australia. J. Zool., Lond. 233:
Hill,J.E. &J.D. Smith(1984): Bats.ANatural History. 318-321.
A NOTE ON SARUS CRANE GRUSANTIGONEMORTALITY
1 1D. UE TO COLLISION WITH HIGH-TENSION POWER LINES
Thesamscrane(Grusantigone)istheonly of the Himalayas. Few long term studies have
resident crane species breeding in India, south beencarriedoutandinformationonitsmortality
108 JOURNAL, BOMBAYNATURAL HISTORYSOCIETY. 98(1). APR. 2001