Ornithofauna and its conservation in the Kuttanad wetlands, southern portion of Vembanad-Kole Ramsar site, India

The avifauna of Kuttanad was studied from January 1995 to June 2007. Two-hundred-and-twenty-five taxa of birds belonging to 15 orders and 59 families were recorded. Among the birds recorded, 38% were migrants. Fifty-five species were found to breed in the area. Family Scolopaceidae showed maximum species diversity. European Roller Coracias garrulus recorded during this study is the first report of this species from Kerala. Ten globally threatened species were recorded. Kuttanad wetland shows greater species diversity, especially in the wetland birds, than the Kole wetlands of Kerala. Kumarakom heronry holds 8% of the biogeographical population of the Near Threatened Oriental Darter. Landscape alteration, hunting, felling of nesting trees and pesticides are the major detrimental factors for the survival of birds. Conservation aspects of birds of this region are discussed.


IntroductIon
Wetlands are complex and productive ecosystems (Maltby 1986;Unni 2002) that occupy about six percent of the Earth's land surface (Maltby & Turner 1983).Wetlands are known as "biological supermarkets" because of the extensive food chains and rich biodiversity they support, providing unique habitats for a wide range of flora and fauna (Mitsch & Gosselink 2000).Wetlands are important habitats for birds, which use them for feeding, roosting, nesting and rearing young (Weller 1999;Stewart 2001).The use of wetlands by birds during the breeding cycle ranges widely, with some depending almost totally on wetlands for breeding, feeding or shelter during their breeding cycles.
Kuttanad wetland is located at the southern portion of India's largest Ramsar site the Vembanad-Kole wetland.Ali (1984), Ali & Ripley (1987), Neelakantan (1996), Chandy (2003), Narayanan (2004), Sreekumar & Narayanan (2004), Rakesh et al. (2004), Narayanan et al. (2005a,b) reported various aspects of the avifauna of this wetland.The only detailed study regarding birds in this region is the midwinter water bird count.Nature Education Society, Thrissur, organized the first water bird survey in the Vembanad Lake (NEST 1993).Since 2001, regular Midwinter Waterbird Count is being carried out at different parts of Kuttanad wetlands by Kottayam Nature Society (KNS) in association with Kerala Forest and Wildlife Department (Sreekumar 2001(Sreekumar , 2002(Sreekumar , 2003(Sreekumar , 2004(Sreekumar , 2005)), but most of the surveys were concentrated in and around the premises of Vembanad Lake.Existing information available on the avifauna of this region is based on surveys conducted by KNS and mainly in view to the wetland birds.Hence this work was taken with the following objectives (i) to make an inventory of the avifauna of Kuttanad wetlands with breeding birds, status, occurrence, (ii) to find and list the major factors which threatens the bird fauna, and (iii) to propose the action plan for the conservation of birds and wetlands of Kuttanad.

Study AreA
Kuttanad is primarily a deltaic formation of five river systems: Meenachil, Pamba, Manimala, Muvattupuzha and Achencovil, located in the fertile low-lying areas of Vembanad Lake (Fig. 1) (Shari & Chitra 2005).It spreads over Alappuzha, Kottayam and Pathanamthitta districts of Kerala and forms an integral part of the Vembanad-Kole Ramsar site.This region lies between 9 0 17'-9 0 40'N & 76 0 19'-76 0 33'E and is separated from the Arabian Sea by a narrow strip of land.Much of this region lies 0.6 to 2.2 m below mean sea level, hence the area remains water-logged almost throughout the year and is subjected to continued flood submergence during the monsoon and saline water ingression during the summer months.Kuttanad is rightly called the "Rice Bowl of Kerala", contributing nearly 20% of the total state rice production.It consists of 53,639 hectares distributed among 1086 units where rice is cultivated (Sudhikumar & Sebastian 2005).Most of these fields are inundated during the non-crop season and water has to be pumped out to the canal systems and backwaters before the commencement of the cultivating season (Sashikumar & Palot 2002).Based on the soils, geomorphology and salinity intrusion, Kuttanad is subdivided into six agro-ecological zones viz., (i) Upper Kuttanad (ii) Kayal lands (iii) Vaikom Kari (iv) Lower Kuttanad (v) North Kuttanad and (vi) Purakkad Kari (Indo-Dutch Mission 1989).Major portion of the Vembanad estuary is situated in Kuttanad Wetland, which is the biggest estuary in the southwest coast of India.It experiences warm climate with fairly uniform temperature throughout the year ranging from 21-36 0 C. Humidity in general is very high all through the year (Shari & Chitra 2005).The average annual rainfall received is around 3000mm (Shari & Chitra 2005) of which about 83% is received during south west monsoon months.

MAterIAl And MethodS
This study was carried out from January 1995 to June 2007.Observations were carried out during the weekdays mainly from 0700 to 1100 hr and occasional sightings of birds during non-birding trips were also included.Birds were identified with the help of different field guides (Ali 1984;Ali & Ripley 1987;Neelakantan 1996;Grimmet et al. 2000;Grewal et al. 2002) using Bushnell (7x35mm) binoculars.The species list (Table 1) includes those that were recorded in the present study and also from various other works, compiled from published and unpublished materials and personal communications.As per the occurrence in the Kuttanad wetlands, species were classified as: resident (R) -found in all suitable habitats throughout the year; migrant (M) -found only during a specific season (this includes birds from Central Asian countries and northern areas of the Indian subcontinent); local migrant (LM) -resident to the state but found in Kuttanad region only during a specific season; straggler from the hill (SH) -species usually found in the hilly areas of the state but recorded from this area; and vagrant (V) -birds which accidentally came to the region from its normal range, which is hundreds of miles away.The status of many birds oberved in Kuttanad Wetland is different from their Kerala State status.Abundance of each species was derived following Nameer et al. (2000).According to the feeding habits, birds were divided as aquatic herbivores, aquatic insectivore, aquatic omnivores, piscivores, carnivores, insectivores, omnivores, granivores, frugivores, nectarivores.The taxonomical classification and common names follow Manakadan & Pittie (2002).

reSultS And dIScuSSIon
Total 225 taxa of birds belonged to 15 orders 59 families were identified from Kuttanad wetlands (Table 1).Neelakantan (1996) listed out 483 species from Kerala out of which around 47% of bird species were recorded during this study.Order Passeriformes posses the most diversified families (26) and species (78).Maximum number of species was recorded from the families Scolopaceidae and Ardeidae (Table 1).Though a wetland-dominated area, 52.5% birds belong to non-wetland category.Most of the land birds were seen at the eastern boundaries of Kuttanad, where Kuttanad wetlands meet midland areas of Kerala.Hence high number of species reported from that area could be due to edge effect.Among the birds recorded, 38% constitute migrants and 38% residents (Fig. 2).Wetland and wetland dependent birds formed major portion of these migrants.The composition of birds in major feeding guilds in the study area showed that the insectivore guild was the most common with 37.33% species, followed by piscivores (Fig. 3).
Ten globally threatened species were recorded.The birds that are of interest owing to their rarity as far as Kerala is concerned, and which were sighted during the period of the study period from Kuttanad region are given below.

Sightings of special interest
Oriental Darter Anhinga melanogaster -Zacharias & Gaston (2003) reported that the Oriental Darter population had declined in Kerala during last three decades.But it is one among the common species of wetland bird of this wetland.Narayanan & Vijayan (2007) recorded about 8% of the South Asian population of Oriental Darter during the breeding season of 2004.
Painted Stork Mycteria leucocephala -A flock of six birds were sighted at Parippu in the Kayal Kuttanad region on 05 January 2000.There were only a handful of sightings of this species from Kerala during the period of study.
Eurasian Spoonbill Platelia leucorodia -four Greater Grey-headed Fish-Eagle Icthyophaga icthyaetus -This species has been recorded from Pathiramanal Island in the Vembanad Lake by Sethumadhavan C.P. and Saju Vasan on 20 January 2002.This is the only record of this species from the Kuttanad part of Vembanad Lake, even though Saju Vasan has another sighting of the same from the Chithrappuzha, Ernakulam District.
Mountain Imperial Pigeon Ducula badia -These are mainly a birds of the forest biotope and it seldom seen on the wetlands.An uncommon bird -first record of this was in 05 August 2003.After the first record, regular sightings during monsoon seasons from the Kayal Kuttanad and North Kuttanad.
Malabar Grey Hornbill Ocyceros griseus -An endemic species of Western Ghats.One individual recorded on 15 January 2005 by P. Manoj (pers. comm. 2005) (Sathyan Meppayur pers. comm. 2008).This is the first report of this species from Kerala.

Major threats to the avifauna of this region
Thanneermukkom salt-water barrage (1250m long) commissioned in 1975 was constructed across the narrow portion of the Vembanad Lake to prevent the saltwater intrusion during summer from sea and to spill out floodwater during monsoon.The Thanneermukkom barrage has greatly influenced the ecology of the region.When this regulator is closed, there is virtually no flow of water beyond it on the southern side making the entire Kuttanad a static pool.At present the barrage is open from 22 December to 22 March.Water with heavy loads of pesticides and fertilizers from the paddy fields were drained into this stagnant water body.Persistence of these kinds of situations triggered several ecological backlashes like proliferation of weed growth, deterioration of the water quality, increased morbidity among the local fish population and destruction of subsistence fishery on which the local fishermen depended (Abhilash et al. unpublished).Barrage also impaired the migration of marine and estuarine fauna.Horizontal and vertical shrinkage of Vembanad Lake, vanishing mangroves, eutrophication, increased interventions in the area by tourism, Thottappally spillway, sewage and industrial pollution etc. are the major problems of Kuttanad wetlands (Abhilash et al. unpublished).The loss of habitat through direct and indirect anthropogenic activities causes immense threat to the birds especially the migratory birds of Kuttanad.The most important threats to the wetland birds are the following.
landscape alteration: The key threat factor is the landscape alteration in Kuttanad.Encroachment of the wetlands for the construction of new buildings and settlements are very common in Kuttanad, even though it is legally banned.Before and after the year 1947, huge area of the Vembanad Lake has been converted to paddy fields to enhance the rising demand for food.This adversely affected the migratory birds such as ducks and teals by reducing available roosting place, foraging areas and food in the lake.Thus the formation of mudflats in the reclaimed areas provided ideal foraging areas for the wintering waders.
hunting: Hunting pressure is intense in some areas of Kuttanad, Sashikumar & Palot (2002) have earlier reported heavy poaching of the birds from this area.The main hunting methods involve a combination of shooting, with hooks and line using fishes as bait, picking of nestlings from nests, especially from heronries.The main species caught by shooting is winter migrants like ducks, godwits and the species belonging to the ardeidae family.Black-crowned Night-Herons and egrets are the species heavily trapped by hook and line method (S.Dipu pers.comm.2004).Heavy poaching of nestlings of Purple Heron from the nests situated in the thickets of Phargmites karka is prevailing in the "R Block" area.
overgrowth of exotic vegetation: Infestation of the exotic waterweeds like Eichhornia crassipes, Slavinia molesta are causing serious harms to the water birds (Sashikumar & Palot 2002), but at the same time this provides foraging areas for the species like Jacanas and Moorhens.Exotic vegetation also poses immense threats to the native flora and fauna of this region.Vembanad Lake is covered by Eichhornia crassipes which is drastically affecting the life of fishermen and local people, who are dependent on this lake for their basic needs.
Pesticides: Intensive use of chemical fertilizers and pesticide as a part of the agriculture activities have played havoc on the traditional farming system and life style of Kuttanad, affecting birds, other wildlife as well as human beings (Sashikumar & Palot 2002).Organochlorine and organophosphate pesticides are widely used in paddy cultivation all over the state.Studies conducted in the Kuttanad ecosystem show that these chemicals are present well above the permissible limits.Seedikkoya & Shukkur (2004) reported the presence of organochlorines such as DDT, DDE, Dieldrin, Aldrin and heavy metals such as zinc (Zn) and copper (Cu) in the Indian Pond Heron, Little Egret Egretta garzetta and Cattle Egret Bubulcus ibis from northern Kerala.But such studies on birds are not yet conducted in Kuttanad.
Felling of nesting and roosting trees: Cutting down of tall trees used by colonial nesting waterbirds is rampant in Kuttanad, and small heronries in Kerala face similar threats from local people.Loss of local flora is huge in Kuttanad wetland.The reduction in size or the total felling of sacred groves has also created trouble in the form habitat loss for land birds and wetland birds; which uses tiny patches for feeding, roosting and nesting.The extent of mangrove trees in the Kumarakom heronry, Pathiramanal has drastically reduced.After the taking over of Kumarakom heronry by KTDC, 13 hectares of the land was given to a venture company by KTDC.They cleared the mangrove belt along the lake and converted them into a lawn and constructed a tourist jetty.With this, a species of mangrove Kandelia candel was totally wiped out from the Kumarakom heronry (Ramachandran & Mohanan 1990;Sreekumar 2001).
tourism: Ali (1984) reported that large flocks of wintering ducks roost in the calm waters of Vembanad Lake.At present, amplified promotion of tourism by using boats and speedboats force migratory ducks to desert roosting place in the lake.Most of the tourist resorts in and around the Vembanad Lake and Kuttanad do not have any proper solid waste and waste-water treatment facilities, therefore all waste materials are dumped into the lake during night hours.This activity adversely affects self-sustaining capacity of the Lake.House boats discharge effluents and wastes directly into the lake and large amount of oil are spilled into the system.In the name of tourism the authorities, which owns the Kumarakom heronry clear pure stands of Phragmites karka, where Black-crowned Night-Heron Nycticorax nycticorax, Median Egret Mesophoyx intermedia, and Large Egret Casemerodius albus nests.This activity has drastically affected nesting habitats of the breeding birds.
Kuttanad wetlands show high diversity in terms of must be developed in all tourist resorts in the Vembanad region.j.All tourist establishments must provide a fraction of money from the yearly profit for the restoration activities of the Kuttanad wetlands through government and local NGO's.
k. Mobile checking facilities should be initiated to seize polluting boats and its license should be withheld.
l.A detailed study on the movements of the birds of this area should be conducted during various seasons to determine the spatial and temporal pattern of bird migration and ecological reasons should be identified to determine the drastic reduction in the population of many bird groups.

concluSIonS
This study increased the information and knowledge available on the avifauna of Kuttanad wetlands.Kuttanad wetland is rich in wetland bird species.Degradation of this unique wetland ecosystem, hunting and habitat alteration is still prevailing in this part of the Vembanad-Kole Ramsar this threatens the birdlife directly as well as indirectly.As Kole wetlands, Kuttanad wetland is also serving as halting area for the trans-continental migrants; urgent measures should be taken to protect this wetland ecosystem for the conservation of birds especially migratory and breeding colonial nesting birds.This region holds more than the estimated number of South Asian biogeographical population of six species of waterbirds.At present the low lands of Kerala are under high threat of landscape modification due to population growth, tourism and other infrastructure developmental activities.Regular monitoring of wetland should be taken up.In-depth studies on the avifauna, especially endangered birds, should be undertaken.Hence urgent conservation measures have to be implemented and a protected area has to be evolved for preserving the remaining tract of mangroves and faunal heritage of this unique region.Local people should be made aware of the importance of wetlands, waterfowl (Sashikumar & Palot 2002) and other common birds.Without the involvement of common people of this region conservation of the wetlands will not be successful.

Figure 3 .
Figure 3. Percentage distribution of feeding guilds of birds in Kuttanad wetland

Table 1 . Checklist of the birds of Kuttanad wetlands with its status Scientific name Common name Status
White Ibis were found to breed during monsoon.Among the colonial nesting waterbirds Oriental White Ibis, Indian Shag Phalacrocorax fuscicollis, Large Egret Casmerodius albus, Median Egret Mesophoyx intermedia were found to breed only in the Kumarakom heronry, and Little Cormorants Phalacrocorax niger and Indian Pond Heron Ardeola grayii were found to nest in more than two areas.Kuttanad wetland support relatively large flocks of Egret spp., Oriental White Ibis, Little Cormorants, Indian Shag, Darter, Glossy Ibis Plegadis falcinellus.
at Kumarakom heronry.A small relict population of this species is still surviving at Ponthanpuzha forest in the midlands of Kottayam District.Individual sighted from Kumarakom would be from the Ponthanpuzha population.European Roller Coracias garrulus -One individual was seen at Erupathinaalayiram paddy fields of Kayal Kuttanad, 29 September 2002.This was the first report of this species from Kerala State.Oriental Dwarf Kingfisher Ceyx erithaca -One individual of this forest species were recorded from Kumarakom heronry on 16 February 2005 by P. Manoj (pers.comm.2005).Rufous Woodpecker Celeus brachyurus -The species was recorded only once from Chennithala in the Upper Kuttanad region on 23 February 1997.Once heard on 10 January 2004 from the tree-dominated area of Ayamanam.This is essentially a bird of the evergreen forests of the hills.Pacific Swift Apus pacificus -A huge flock of around 2000 individuals from Kumarakom and adjacent areas (north Kuttanad and Vaikomkari divisions) by David V. Raju (pers.comm.2006) and various visiting birders to this area on 24-26 December 2006 and a flock of more than 500 individuals on 29 December 2006.Pale Martin Riparia diluta -Sighted and photographed by Sathyan Meppayur, Tim Inskipp and Carol Inskipp from Pathinaalayiram paddy fields on 04 December 2006