Behavioural and virological studies on a rescued Oriental White-backed Vulture Gyps bengalensisfrom western Maharashtra, India
Satish Pande 1, Pranav Pandit 2, Aditya Ponkshe 3, Ram Mone4, Shailesh Pawar5 & Akhilesh Mishra6
1-4 Ela Foundation, C-9, BhosalePark, Sahakarnagar-2, Pune, Maharashtra411009, India
5,6 National Institute of Virology, Microbial Containment
Complex, 130/1, Sus Road, Pashan,Pune, Maharashtra 411021,
India
Email: 1 pande.satish@gmail.com, 2 pranav.vet@gmail.com,
3 ponkshe.aditya@gmail.com, 4 moneram@gmail.com,
5 pawarshailesh@hotmail.com (corresponding author),
Date of publication (online): 26 January
2011
Date of publication (print): 26 January
2011
ISSN 0974-7907 (online) | 0974-7893
(print)
Editor: William Dundon
Manuscript details:
Ms # o2471
Received 28 May 2010
Final received 20 December 2010
Finally accepted 25 December 2010
Citation: Pande, S., P. Pandit, A. Ponkshe,
R. Mone, S. Pawar & A. Mishra (2011). Behavioural and virological studies on a rescued Oriental White-backed Vulture Gypsbengalensis from western Maharashtra,
India. Journal of Threatened Taxa 3(1): 1490-1492.
Copyright: © Satish Pande, Pranav Pandit, Aditya Ponkshe, Ram Mone, Shailesh Pawar & Akhilesh Mishra 2011. Creative
Commons Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in any medium
for non-profit purposes, reproduction and distribution by providing adequate
credit to the authors and the source of publication.
Acknowledgements:We
are grateful to the Forest Department, Maharashtra, for inviting us for the
examination of the vulture, for local hospitality and for the necessary
permissions. Mr. Prashant Deshpande,Ela Foundation for support in field work and staff of
the Avian Influenza department for the laboratory assistance.
On 05 August 2008 a villager witnessed a large raptorial
bird descending from the sky and landing on the ground, in an open field at Bhangaon Village, Shrigonda Taluk (18061’N & 74069’E), Pune District, Maharashtra, India. The bird looked exhausted and was unable to
fly. When approached it assumed a
drooping neck posture. The raptor was
caught and was handed over to the forest department at Shrigonda. This is a
semi-arid region on the Deccan Plateau interspersed
with agricultural cropland, scrub areas and villages. This bird was identified as the Critically Endangered Oriental White-backed Vulture Gyps bengalensis. The vulture was kept in a nursery and offered
500g of fresh raw beef daily. After an
unsuccessful release attempt after five days in the nursery, it was kept in
captivity for another week.
It has been reported that two species of
vultures, the Indian White-backed Vulture and the Long-billed Vulture Gyps indicus,
have declined in population by more than 90% throughout India (Green et al.
2004; Shultz et al. 2004). Affected
birds exhibit signs of illness (neck drooping syndrome) for approximately 30
days prior to death (Cunningham et al. 2003; Watson et al. 2008). Epidemiological observations have been found
to be consistent with an infectious cause for this morbidity and mortality
(Cunningham et al. 2003). We undertook
further investigations on this bird because vultures are threatened with
extinction and, therefore, it is of the utmost importance to investigate the
causes of morbidity and mortality in these birds. With the permission of the forest department,
samples for laboratory tests including haematology and virologicalstudies were collected. The samples
collected were blood, serum, cloacal and tracheal
swabs. Virological investigations were
performed at the National Institute of Virology
(NIV), Pune, India. Fresh faecal samples were also examined for parasites and the bird was
closely checked for the presence of ectoparasites. During this time the vulture, although active
(e.g. flapping its wings often), appeared to be emaciated.
When the vulture was observed from outside
of the room in which it was being nursed, it perched erect with its neck
extended, alertly scrutinizing its surroundings. However, when the vulture was approached by
entering the room, it adopted a posture indicative of thanatosis,
a behaviour of birds in which they exhibit neck drooping and feign death
(Watson et al. 2008). When touched, the
vulture gave the typical threat display of extended wings, flared body
feathers, jabbed with its powerful beak and lashed out with one foot in a
threatening manner. Upon retreating, the
neck drooping posture was not resumed and the wings were kept extended for some
time.
The biometry and haematological findings
of the captive individual were as shown in Table 1. Blood parasites including Plasmodium species were specifically
looked for because they have been described as one of the causes of morbidity
in vultures (Sudhan et al. 2004). Parasites were not seen in the blood smear.
India experienced several outbreaks of highly pathogenic avian
influenza (HPAI) H5N1 in domestic poultry from 2006 to 2009 in parts of the
western and northeastern states; namely Maharashtra and Gujarat, Madhya Pradesh,
West Bengal, Assam and Tripura (Chakrabartiet al. 2009). Avian influenza (AI)
surveillance in wild migratory, wild resident, domestic birds and poultry was
undertaken by the NIV jointly with the ElaFoundation, Pune, India from 2006 to 2008 and various
bird samples were screened for HPAI H5N1 and other AI viruses (Pawar et al. 2009). To rule out the possibility of infection with AI viruses and other viral
infections, cloacal, tracheal and serum samples were
collected from the vulture. The cloacal and tracheal samples were transported in viral
transport medium (Hank’s balanced salt solution) with antibiotics (Penicillin,
Streptomycin, Gentamycin, AmphotericinB) (WHO 2002). All of the samples were
transported to the laboratory by cold-chain.
Cloacal and tracheal samples of the vulture were negative for AI viruses,
Newcastle Disease Virus (NDV), Infectious BursalDisease Virus by virus isolation. Serum
was negative for the presence of antibodies against AI H5N1, H5N2, H9N2, H7N1,
and NDV by the haemagglutination inhibition test. Theectoparasites found included a few unidentified bird lice.
The vulture was ringed and it gained 1.5kg
during the captivity period. There were
no signs of bone injury or soft tissue trauma. On 24 July 2008, when a guard opened the door to feed the
vulture, it escaped and flew away.
Two days later, at about 0630hr, a farmer reported sparking followed by the sound of an
explosion from overhead live electricity wires. He found a large dead bird on the ground underneath the wires, partially
burnt and still smoking. He noticed the
ring on the leg of the bird and contacted us. The location of the bird was Parner, Maharashtra about 60km from the point of release. Subsequent necropsy revealed ecchymosis on the pectoral muscles. As there was no evidence to suggest visceral
gout diclofenac estimations were not performed.
The neck-drooping behaviour,
that the vulture had intermittently exhibited in captivity, was
previously thought to be a sign of illness but it is now thought to be a
mechanism of thermoregulation as well as a predator avoiding strategy
especially when in close proximity to humans (Watson et al. 2008). We suggest that the neck-drooping behaviour
observed by us could have been due to a predator avoidance strategy and not due
to visceral gout. Neck-drooping has been
previously associated with visceral gout which is caused by the ingestion of
the drugs Diclofenac and Ketoprofenused to treat domestic livestock (Cunningham et al. 2003). We feel that such neck drooping is exhibited
when a solitary vulture is approached by humans but, while feeding in flocks,
this behaviour is not usually exhibited, even when humans approach. Vultures in flocks either ignore human
presence or make threatening displays by sudden wing flapping and neck
extension or they fly away for some distance if approached. We have observed such flock behaviour on
innumerable occasions over the past 25 years (Pandeet al. 2003). To summarize, no viral
infection or toxicity was responsible for the morbidity observed in the vulture
under investigation. The neck drooping
behaviour reported here and which has previously been observed by others, was
interpreted, in this context, as a predator avoiding strategy and, therefore,
not due to illness. In addition, our
report suggests that electrocution may also be an explanation for the
decreasing numbers of vultures in India.
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