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Bioscience Discovery, 4(1): 96-99, Jan. 2013 ISSN: 2229-3469 (Print)

HOME RANGE USE OF WINTER MIGRATORY VULTURES IN AND AROUND JORBEER, BIKANER (RAJASTHAN) INDIA

Prabodh Chander Khatri

Environment and Wild Life Researcher, Desert Wild Life Society, Bikaner (Rajasthan) INDIA

prabodhchander@yahoo.com

ABSTRACT The home range characteristics of vultures were examined in winters at Jorbeer and surrounding areas of Bikaner district (Rajasthan). The winter migratory vultures at Jorbeer have occupied 8640 Square Km. area as their home range. Seven species of vulture were recorded during study period October 2006 to March 2011 viz. the King Vulture (Sarcogyps calvus), Cinereous Vulture (Aegypius monachus), Egyptian Vulture (Neophron percnopterus), Eurasian Griffon Vulture (Gyps fulvus), Himalayan Griffon Vulture (Gyps himalayensis), Long billed Vulture (Gyps indicus) and white Backed Vulture (Gyps bengalensis). The home range of each species was overlapped and covering 74 villages between latitude 27

035' North to 28

030'

North and 72052' East to 73

049' East longitude. Food availability for vultures appears to be

strong factor as they are able to adjust their home ranges and foraging opportunities. The study has established home ranges of different vultures during winter migration.

Keywords: Migratory vultures, Gyps fulvus, Aegypius monachus, Gyps bengalensis

INTRODUCTION Raptors are often at the top of the food chain in many ecosystems, which makes them ideal indicators of ecosystem health. If raptors in nature are threatened, then other animals in that ecosystem also are at risk. Raptors are birds of prey that feed primarily on meat taken big hunting or on carrion. The term 'Raptor" is derived from the Latin word rapere, which means "to seize". Vultures are able to adjust their home ranges, movements, patterns and flight behavior to local conditions, especially those related to habitat structure and foraging opportunities. The home range is managed for the total economics of energy requirement of the social group i.e., home range should suffices food, feeding and energy requirements of a social group. Thus the home range for a particular species is the area of safety security, roosting, feeding, resting, moving, playing and nesting. Home-range sizes and time spent soaring were much greater than reported for vultures residing in an agricultural landscape. Food resources at the heavily forested site were fewer and less predictable than in agricultural landscapes, requiring large home ranges and increased time spent foraging (Travis et al., 2004).

Nine species of vultures are recorded in Indian subcontinent (Ali and Ripley, 1983) of which seven species have been observed in and around Jorbeer area, Bikaner (Rajasthan), India (khatri, 2013). The seven species of vultures are long billed vulture (Gyps indicus), White Backed Vulture (Gyps bengalensis), Eurasian Griffon Vulture (Gyps fulvus), Himalayan Griffon Vulture (Gyps himalayensis), King Vulture (Sarcogyps calvus), Cinereous Vulture (Aegypius monachus) and Egyptian Vulture (Neophron percnopterus) come and stay in winters in Jorbeer and surrounding areas of Bikaner. Home range for vultures especially during winter migration has not been studied as per literature. This paper explains home range use of seven species of vultures in Jorbeer and adjoining areas of Bikaner. MATERIALS AND METHODS Study site The study area Jorbeer of Bikaner district (Rajasthan) is situated in the Western part of the "Thar" desert. Jorbeer situated South-East to Bikaner at distance of 12 Km. from city. The geographical location of area is 20'30 North latitude and 73'50 East longitudes at height of 234.84 MSL.

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Prabodh Chander Khatri

The climate is dry with an average annual rainfall 100mm and temperature ranges from a minimum of -10C to -20C in winters to a maximum of 49.50C in summer. The vegetation of the region is thorny and scanty and composed of scattered trees like Salvadora Oleodies, Prosopis cineraria, Shurbs such as Zizipus mummularia and grasses Lasiuruss indicus, Panicum antidotale etc. Approximately 20-35 carcasses were dumped each day by municipal board of the site providing a regular source of food to scavenging birds. A Survey has conducted to study the home range of seven species of vultures in Jorbeer and 40-80 km. around the Jorbeer area in Bikaner district from October, 2006 to March, 2011 and collected information through questionnaires from local people of nabouring villages. The home ranges of different vultures have been calculated by using scale 1cm = 8 km. The total 8640 square / kilometer home range for seven species of vultures between 27035' North to 28030' North and longitude 72057' East to 73049' East has been calculated. Population data of 74 villages obtained for research study. The home range area is being

overlapped by all the species of vultures. The home range covered by individual species was observed and analysed in details. RESULTS AND DISCUSSION The area of home range depends upon the population, body size and number of carcasses available in home range i.e. when the number of carcasses is low the home range will love to large area and vice-versa. The size of home range is more or less a characteristic feature of particular species of bird. The vultures of Jorbeer area were almost migratory and stays in 8640 sqyare/Km. area at Bikaner district during winters. Few Egyptian vultures are resident vultures. All the vultures species were observed to occupy their home range as follows: Long billed vulture 1440 Sq/Km., White Backed vulture 1584 Sq/Km., Eurasian Griffon vulture 4680 Sq/Km., Himalayan Griffon vulture 4680 Sq/Km., King vulture 1728 Sq/Km., Cinereous vulture 4680 Sq/Km. and Egyptian vultures 8640 square/Kilometers (Table - 1)

Table 1 : Showing Home Range (8640 Sq/Km.) covered by different vultures at Jorbeer and surrounding areas of Bikaner. Scale : 1 cm - 8 Km.

S.No. Name of Vulture Area covered by the bird

(Square/Kilometer)

Percentage area covered by the

Vulture (%)

1. Long billed Vulture 1440 16.66%

2. White Backed Vulture 1584 18.33%

3. Eurasian Griffon Vulture 4680 54.16%

4. Himalayan Griffon Vulture 4680 54.16%

5. King Vulture 1728 20%

6. Cinereous Vulture 4680 54.16%

7. Egyptian Vulture 8640 100%

The home range of each species was overlapped and covering a total of 74 villages covering 8640 Square/kilometer area between latitude 27035' North to 28030' North and 72052' East to 73049' East Longitude. Approximately 1 to 30 carcasses were recorded during survey in various villages for these birds. The seven species vultures while staying for the six to seven months were observed to visit the near village area of Bikaner district for feeding as their home range. Considerable work has been devoted to examining factors that affect

interspecies vision in home range size. Home range for most vertebrates increase with body mass and decrease with increase habitat productivity. (McNab, 1963, Harestad and Bunnell, 1979) (Fig. 1). The maximum population of seven vultures species were recorded at Jorbeer i.e. 919 vultures in year 2005-2006, 999 vultures in 2006-2007, 1058 vultures in 2007-2008, 1130 vultures in 2008-2009, 1232 vultures in 2009-2010 and 1324 vultures in 2010-2011.

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Fig. 2(a): Showing general Ecology: Trees Prosopis cineraria the shelter of Vultures at Jorbeer

Fig. 2(b): Showing desert dunes with thorny bushes, trees and a group of Griffon vultures at Jorbeer

Large species have high energetic requirements and presumably must occupy large home ranges to obtain sufficient food. Raptor home ranges are determined by food availability (Marquirs and Newton, 1981). The increase in Eurasian Grriffon Vultures was studied as related to livestock availability at Jorbeer, Bikaner in winters. The

feeding and roosting sites both were close together at Jorbeer, indicates the high suitability of carcass dumps us food sources for Eurasian Griffon Vultures (Khatri, 2012). Home range size of raptors increases with body mass and predatory birds have large home ranges than similar sized non-predatory birds (Schanear, 1968).

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Prabodh Chander Khatri

The raptors that consume large prey to have small home ranges and also increases with latitude, as they do for mammals (Horestad and Bunnell, 1979, Lindstedt et al., 1986) (Fig-2).

Travis et al., (2004) explained that food resources at heavily forested sites were fewer and less predictable than in agricultural landscapes, requiring larger home ranges and increased time spent foraging. Foraging ranges and total home range area of raptors are known to be influenced by prey abundance and prey accessibility, next location, the total amount of available suitable

foraging habitat within the home range, and type of vegetation (Wekeley 1978, Baker and Brooks 1981, Bechard 1982, Schmutz 1987, Woodbridge 1991). The results of this study suggest that seven vultures species are able to adjust their home ranges and movement patterns to local conditions, especially those related to habitat structure and foraging opportunities. However, in areas where the land use includes a predominance of cover types with a continually available prey base and abundant prey populations.

LITERATURE CITED Ali S and Ripley SD, 1983. Handbook of the Birds of India and Pakistan, compact edition, Oxford University Press, Bombay. Baker JA and Brooks RJ, 1981. Distribution paterns of raptor in relation to density of meadow voles. Condor, 83: 42-47. Bechard MJ, 1982. Effect of Vegetative Cover on foraging site selection by Swainson'sHawk. Condor, 84: 153-159. Harestad AS and Bunnel EL, 1979. Home range and body weight - A revaluation. Ecology, 60(2): 389-402. Hmutz JK, 1987. The effect of agriculture on ferruginous and swainson'shwaks. J. Range Manage, 40(5): 438-440. Khatri PC, 2012. The increase in the population of Eurasian Griffon vultures (Gyps fulvus) at Jorbeer, Bikaner : carcass dump as key habitats for winter migration in the Griffon vultures. International Journal of Geology, Earth and Environmental Sciences, 2(2): 157-162. Khatri PC,2013. Status of migratory vultures at jorbeer, Bikaner (Rajasthan). Life sciences leaflets 1:6-13 Lindstedt SL, Miller BJ and Buskirk S.W, 1986. Body size, time and home range size in mammals. Ecology, 67 : 413-418. Mcnab BK, 1963. Bioenergetics and determination of home range size. American Naturalist, 97:133-140. Marquiss M and Newton I 1981. A radio-tracking study of the ranging behaviourand dispersion of European Sparrowhawks.Journal of Animal Ecology, 51 : 111-133. Schoenear TW, 1968. Sizes of feeding territories among birds. Ecology, 49: 123-14 Travis L, Bradley Reinhart D, Lehr Brisbin JR and Olin Rhodes E, 2004. Home ranges of sympatric Black and Turkey Vultures in South Carolina.The condor, 106:706-711. Wakeley JS, 1978. Factors affecting the use of hunting sites by ferruginous hawks. Condor, 80:316-326. Woodbridge B, 1991. Habitat selection by nesting Swainson's hawks : a hierachial approach. M.Sc. thesis, Humboldt State University, Arcata, CA U.S.A.

How to Cite this Article: Prabodh Chander Khatri, 2013. Home range use of winter migratory vultures in and around Jorbeer, Bikaner (Rajasthan) India. Biosci. Disc., 4(1):96-99.