Wintering birds in and around the vicinity of Lake Mansar , district Udhampur ( J & K )

A systematic survey of Mansar was done from 2004 – 2007 periods in order to check the status of wintering birds. The most important specialty of this area is a lake which has been given the status of wetland and is known as Lake Mansar. This lake serves as a major aquatic habitat and feeding ground for the migratory birds during the winter season. The elevation of Lake Mansar is 666 m above sea level in the Shivaliks terrain of Jammu. A total of 21 species of wintering birds were reported from the study area. These 21 species include true winter migrants as well as local migrants. Among 17 winter migrants, 8 species were found to be of waterfowls and rest 9 species includes Herons, Bittern as well as Steppe Eagle. Besides this, 4 species were observed to be residents but show local migration in the months of winter thereby increasing their number. Coots were found to be first among the winter migrants to arrive in the study area. Moreover, their number was also found to be the maximum (96 ).


INTRODUCTION
India is known to be one of the 12 most important mega diversity centers of the world.India with varied habitats harbours a rich bird life.Aves constitute the most important phylum of animal kingdom.Avifauna is an important biological resource and a component of natural ecosystem.The Indian region with varied habitat harbours an incredibly rich bird life.Moreover, birds were regarded as the indicators of environment.The study of bird communities has been a major area of research in community ecology.
Migration can be defined as the seasonal movement of species from one place to another.Bird migration has been defined in a very appropriate way by Marten Duncan-"Many species in the colder regions of the world seek on the approach of winter, other lands, where more congenial conditions prevail and suitable food in sufficient quantity may be found.The return of spring, however, sees them once again on the wings, making their way back to their old breeding grounds and even, as a general rule, seeking the same nesting site.The autumn migration as a whole may be said to be a journey from the arctic and temperate zones of Nor thern hemisphere to countries lying to the equator in a more or less Southerly direction i.e. as forming a general southward movement.In the Northern Europe, there is a good deal of migration taking place in west to east direction." The present study was carried out to highlight the importance of Lake Mansar which is important from habitat point of view for the aquatic migratory birds.Moreover, Lake Mansar has also given the status of Ramsar site.
A review of literature reveals that migratory ducks use non-breeding habitat for seven months So the aim of present work is to find out the number of migratory species in Mansar especially of the aquatic waterfowls.Besides this, the aim of this present paper is to gather sufficient information regarding the ecology of waterfowls like habitat preference, feeding and sexual dimorphism.

Study area
The study area, village Mansar lies between 30° 45' 5" to 33° 42' 36" North latitudes and 75° 8' 32" to 73° 9' 8" East Longitutes.It is situated about 65 km North-East of Jammu city.The elevation of Lake Mansar is 666 m above sea-level in the Shivaliks terrain of Jammu.Lake Mansar is one of the oldest lakes located in Jammu Shivaliks, fringed by forests and which harbours an interesting aquatic biota.It is situated along the North -South flyway Palearctic-Oriental migratory route of Waterfowl.Lake surface area is about 0.58 Km² and Lake Basin area is 1.67 Km².The maximum depth is 38.25 m.The lake mean width is 490 m and means depth is 20.23 m.Lake Mansar is warm monomictic waterbody.The lake is a structural feature created by Mansar Fold, occurring as a tight fold.It is surrounded by number of villages and seasonal Choes and Khads.

Methodology
The study area was surveyed for recording diversity and population dynamics of wintering birds by applying Line transect method, Sale and Berkmuller 9 (1988) and Point transect method, Verner 10 (1985).Census were made weekly during the study period at different hours of the day.The main transect made during the investigation was the circumference of lake.The abundance of migratory birds was recorded by observing species with the help of Binoculars (Bushnell 7 x 50 U.S.A made).Photography was done with the help of Canon T-70 camera fitted with 300mm zoom lens, digital camera and video camera in order to identify the avian species.

RESULTS AND DISCUSSION
The total number of bird species recorded was enlisted in (Table 1).Among the 21 species recorded, 8 species constitute the migratory waterfowls.These utilize the wetland either to tide over winter for a short period during their migratory spell.Coots were the first to arrive in the study area during the month of October.Mallard, Shoveller, Gadwall, Common Pochard, Coot, Pintail, Wigeon and Tufted Pochard were found to stay in the study area during winter months (October to March).An increase in the number of resident birds i.e.White Breasted Waterhen, Moorhen, Little Egret and Pond Heron was also observed showing a case of local migration.The increase in the number of these species for wintering months may be attributed to availability of space and food resources.Other migratory species includes White Wagtail, Grey Wagtail, Indian Grey Shrike, White Capped Water Redstart, Darter, Night Heron, Grey Heron, Black Bittern and Steppe Eagle.These were sited in the months of October, November, December and January.
During the migration period, waterfowls showed gregarious behaviour besides daily activities like feeding, resting, dabbling and preening.Similar findings were made by Tamisier 11 (1972).Among all these activities, the main were found to be resting as well as feeding.This observation goes well with that of Hepp 12 (1982).
A sudden decline was observed in the diversity as well as population dynamics of migratory avifauna in Mansar.During the year, 2006-2007 the decline was upto such an extent that only 2 species of migratory waterfowls i.e.Mallard and Coot used to visit Lake Mansar (Table 2).This sudden change was attributed to a number of anthropogenic activities which still prevails there.If these activities get promoted, it may be possible that in the near future no migration will take place which will change the status of the waterbirds as well as also leads to wretched condition of this attractive spot.Anthropogenic factors prevailing in Mansar includes: Removal of vegetation cover, introduction of exotic carps, diversion of water channel which effects the level of lake water, draining of lake water, conversion of paddy fields for construction purpose, washing of clothes, cattle bathing and boating.Moreover, implementation of mobile phone towers by the telecom department also serves as a criterion for the decline in the migratory rate of waterfowls as these towers alters the migratory routes.

Table 2 :
Showing Population Dynamics of Migratory Avifauna of Mansar during Wintering Months of Year 2004, 2005, 2006 and 2007 S. Name of Bird Oct. Nov. Dec.Jan.Feb.Mar.Oct. Nov. Dec.Jan.Feb.Mar.Oct. Nov. Dec.Jan.Feb.Mar.