- Email: [email protected]
Unexpected visitors to the Seychelles
CONSERVATION A R O U N D THE WORLD
UNEXPECTED VISITORS TO THE SEYCHELLES
It is well known that the Seychelles, occupying an isolated position in the western Indian Ocean, are of particular interest to zoologists and botanists alike mainly because of the large number of endemic organisms which have evolved and still survive there. Ornithologically, the islands are important from this standpoint, and also because several of them support large populations of breeding seabirds, some of which are of economic importance. During my two-year residence it has been apparent that the islands are of interest to ornithologists from a third point of view--the occurrence there of a wide variety of migrant birds. Between the Seychelles and Madagascar, 965 km to the south-west, lies a string of atolls and sand cays, but to the west, north and north-east a minimum of 1,600km of uninterrupted ocean separates the Seychelles from the nearest land masses. The majority of the migrants so far recorded are birds from the palaearctic which usually winter in equatorial or southern Africa, and their time of arrival in the Seychelles (late August to late November) suggests that they have made the long sea crossing from the north rather than island-hopping from the south-west. Most of the species recorded are undoubtedly strays which have been diverted, possibly by wind, from their normal migration routes, but some species, amongst which shorebirds figure prominently, are of regular annual occurrence, and a small proportion of these also spend the northern summer in the islands. It would be interesting to know here whether the same individuals return to the Seychelles each year, but so far no marking of these birds has been undertaken. Two places appear to be especially attractive to arriving migrants. Shorebirds tend to concentrate on a small (about 10 ha) mudflat in Victoria, the port of the largest island Mahe, while the majority of land birds have been recorded on Bird Island, the northernmost island of the group, lying 97 km to the north of Mahe. The Victoria mudflat certainly constitutes an important
feeding area for Seychelles shorebirds, with between 400 and 600 birds utilizing the area during the northern winter. The main species involved are curlew sandpipers (Ca[idris ferruginea), greater sand plovers (Charadrius Ieschenaultii), grey plovers (Squatarola squatarola), whimbrel (Numenius phaeopus), greenshank (Tringa nebularia) and turnstone (Arenaria interpres). Small numbers of terek sandpiper (Xenus cinereus), common sandpipers (Actitis hypoleucos), lesser sand plovers (Charadrius mongolus), ringed plovers (Charadrius hiaticula) and little stints (Calidris minuta) have also been regularly seen, and the area has produced the first Malagasy records of little ringed plover (Charadrius dubius), golden plover (Pluvialis dominica), knot (Calidris canutus) and long-toed stint (Calidris subminuta). In addition to these shorebirds, lesser black-backed gulls (Larusfuscus), black-headed gulls (thought to be L. brunni-cephalus, but this requires substantiation), gull-billed terns (Gelochelidon nilotica), white-winged black terns (Chlidonias lecopterus), white-cheeked terns (Sterna repressa) and a flamingo (Phoenicopterus ruber) have been recorded. This mudflat is thus of great ornithological interest, but in the context of world populations the number of birds is too small for the area to be regarded as an important wintering area for the species involved. Nevertheless, it seems a pity that a motorway linking Victoria with Seychelles airport will, if built, pass across this interesting habitat. The importance of Bird Island as a receiving area for migrants is less easy to evaluate. Of the smaller islands, only Bird and Cousin have had resident ornithologists on them, and of these two Bird Island has certainly had more than its share of migrants. However, large open expanses (the sooty tern colony and an airstrip under construction) on Bird Island probably increase the chances of seeing migrants compared with the more densely vegetated Cousin Island but, being the first island that birds travelling from the north will encounter, Bird Island may genuinely be more attractive than other islands of the group. Of the 74 species recorded on the island over
218 Biological Conservation, Vol. 6, No. 3, July 1974--~) Applied Science Publishers Ltd, England, 1974--Printed in Great Britaia
Conservation Around the Worm 75 per cent are migrants, and they included, in addition to western, central and eastern Palaearctic birds, a broad-billed roller (Eurystomas glaucurus), presumably blown off course on its return from Africa to its breeding grounds in Madagascar. The majority of the species which have arrived on the island during the last two years are probably no more than strays, for example little whimbrel (Numenius minutus), pectoral sandpiper (Calidris melanotos), corncrake (Crex crex), purple heron (Ardea purpurea), European nightjar (Caprimulgus europaeus), grey wagtail (Motacilla ¢inerea) and ortolan bunting (Emberiza hortulana). Two species which have until recently been regarded as stray visitors to the Seychelles, the yellow wagtail (Motacilla tiara) and tree pipit (Anthus trivialis), appear to winter regularly in small numbers on Bird Island. Other birds, such as ruff (Philomachus pugnax), pratincole (Glareola maldivarum or G. pratincola), Caspian plover (Charadrius asiaticus), cuckoo (Cuculus canorus), European roller (Coracias garrulus), hobby (Falco subbuteo) and golden oriole (Oriolus oriolus), now appear to be irregular visitors in small numbers rather than just strays, and this list may well be extended if observations can be continued over a number of years, as indeed may the list of strays. Under the Wild Animals and Birds Protection Ordinance, 1961, all migrants, except some of the larger shorebirds, are protected. This legislation, however, is relatively ineffective, and certain protected endemic birds and seabirds are still killed. Most of the migrants are sufficiently scarce, and also more wary than the endemic birds, to avoid human interference, but many arrive in a weak state and may fall prey to introduced predators such as rats and cats. Although the Seychelles are not important as a migration stop-over or wintering area for Palaearctic migrant bird populations, that so many species do find their way to such an isolated group of islands is of considerable interest. With the help of the owners of Bird Island, Mr & Mrs Guy Savy, records of migrant birds on this island will be kept over the forthcoming years. The future of Victoria mudflats, and of the availability of people competent to observe birds on them, is less certain, but hopefully the high ornithological interest of this area will not be entirely overlooked during considerations of developments for or associated with the growing tourist industry of the islands.
CHRISTOPHER J. FEARE,
Culterty Field Station, Newburgh, Ellon, Aberdeenshire AB4 0AA, Scotland
219
SRI LANKA'S GAL OYA NATIONAL PARK: ASPECTS AND PROSPECTS
Of the four wildlife national parks in Sri Lanka (Ceylon) (Crusz, 1973), the Gal Oya National Park holds out the greatest variety of prospects. It was proclaimed in 1954, less than three years after Sri Lanka's largest man-made lake, the Gal Oya reservoir (Senanayake Samudra), was formed through the damming of the Gal Oya (river) at Inginiyagala. It covers an area of 100 square miles (259sqkm), skirting the periphery of the star-shaped reservoir of which it forms part of the catchment area (Fig. 1). What little access there is to it is by boat or by jeep roads. The reservoir itself (36 square miles = 93 sq km) was declared a wildlife Sanctuary at the same time (Fig. 2). The Park consists mainly of damanas (parklands or savannas), with scattered belts of high forest close to rivers and streams and persisting as patches on the slopes of the western foothills. It is very undulating, and the smaller watercourses running across it, though bone-dry for most of the year, carry an enormous flow during the North-East Monsoon. The three main rivers (Balabedde Oya, Gal Oya, and Sellaka Oya) that flow into the reservoir pass through the Park. The famous Danigala range of hills, closely associated with the Sitala Vanniya aboriginal Veddahs, runs due north-south and falls within the Park. Large rock outcrops (inselbergs), stud the landscape constituting dramatic profiles, and there are also several caves, which until recent times were used by the Henebedde Veddahs as one of their strongholds, though such aboriginal peoples have now almost disappeared. Ancient ruins are also found within the Park. The soil is mostly rocky or gravelly and very shallow, being therefore of very poor water-storage capacity and agricultural usefulness. During the greater part of the drought season the whole area is dry except for the perennial streams. With their vast expanse of tall grass and scattered trees of all types and shapes, the damanas provide a beautiful landscape. The grasses, which are mostly illuk (lmperata cylindrica) and mana (Cymbopogon confertiflorus), grow to a height of over 5 ft (1.5 m) at the end of the North-East Monsoon season. It is well-nigh impossible to get through them then, as they are not only tall but matted together. In certain lowlying areas (dopaths) there are shorter grasses, mainly Cynodon dactylon, Ischaemum ciliare, and Aristida setacea. When the damanas are burnt, through human activity or lightning, they become talawas in which the fire-resistant trees survive. Several types of trees are found in damanas, the dominant ones being the
UNEXPECTED VISITORS TO THE SEYCHELLES
It is well known that the Seychelles, occupying an isolated position in the western Indian Ocean, are of particular interest to zoologists and botanists alike mainly because of the large number of endemic organisms which have evolved and still survive there. Ornithologically, the islands are important from this standpoint, and also because several of them support large populations of breeding seabirds, some of which are of economic importance. During my two-year residence it has been apparent that the islands are of interest to ornithologists from a third point of view--the occurrence there of a wide variety of migrant birds. Between the Seychelles and Madagascar, 965 km to the south-west, lies a string of atolls and sand cays, but to the west, north and north-east a minimum of 1,600km of uninterrupted ocean separates the Seychelles from the nearest land masses. The majority of the migrants so far recorded are birds from the palaearctic which usually winter in equatorial or southern Africa, and their time of arrival in the Seychelles (late August to late November) suggests that they have made the long sea crossing from the north rather than island-hopping from the south-west. Most of the species recorded are undoubtedly strays which have been diverted, possibly by wind, from their normal migration routes, but some species, amongst which shorebirds figure prominently, are of regular annual occurrence, and a small proportion of these also spend the northern summer in the islands. It would be interesting to know here whether the same individuals return to the Seychelles each year, but so far no marking of these birds has been undertaken. Two places appear to be especially attractive to arriving migrants. Shorebirds tend to concentrate on a small (about 10 ha) mudflat in Victoria, the port of the largest island Mahe, while the majority of land birds have been recorded on Bird Island, the northernmost island of the group, lying 97 km to the north of Mahe. The Victoria mudflat certainly constitutes an important
feeding area for Seychelles shorebirds, with between 400 and 600 birds utilizing the area during the northern winter. The main species involved are curlew sandpipers (Ca[idris ferruginea), greater sand plovers (Charadrius Ieschenaultii), grey plovers (Squatarola squatarola), whimbrel (Numenius phaeopus), greenshank (Tringa nebularia) and turnstone (Arenaria interpres). Small numbers of terek sandpiper (Xenus cinereus), common sandpipers (Actitis hypoleucos), lesser sand plovers (Charadrius mongolus), ringed plovers (Charadrius hiaticula) and little stints (Calidris minuta) have also been regularly seen, and the area has produced the first Malagasy records of little ringed plover (Charadrius dubius), golden plover (Pluvialis dominica), knot (Calidris canutus) and long-toed stint (Calidris subminuta). In addition to these shorebirds, lesser black-backed gulls (Larusfuscus), black-headed gulls (thought to be L. brunni-cephalus, but this requires substantiation), gull-billed terns (Gelochelidon nilotica), white-winged black terns (Chlidonias lecopterus), white-cheeked terns (Sterna repressa) and a flamingo (Phoenicopterus ruber) have been recorded. This mudflat is thus of great ornithological interest, but in the context of world populations the number of birds is too small for the area to be regarded as an important wintering area for the species involved. Nevertheless, it seems a pity that a motorway linking Victoria with Seychelles airport will, if built, pass across this interesting habitat. The importance of Bird Island as a receiving area for migrants is less easy to evaluate. Of the smaller islands, only Bird and Cousin have had resident ornithologists on them, and of these two Bird Island has certainly had more than its share of migrants. However, large open expanses (the sooty tern colony and an airstrip under construction) on Bird Island probably increase the chances of seeing migrants compared with the more densely vegetated Cousin Island but, being the first island that birds travelling from the north will encounter, Bird Island may genuinely be more attractive than other islands of the group. Of the 74 species recorded on the island over
218 Biological Conservation, Vol. 6, No. 3, July 1974--~) Applied Science Publishers Ltd, England, 1974--Printed in Great Britaia
Conservation Around the Worm 75 per cent are migrants, and they included, in addition to western, central and eastern Palaearctic birds, a broad-billed roller (Eurystomas glaucurus), presumably blown off course on its return from Africa to its breeding grounds in Madagascar. The majority of the species which have arrived on the island during the last two years are probably no more than strays, for example little whimbrel (Numenius minutus), pectoral sandpiper (Calidris melanotos), corncrake (Crex crex), purple heron (Ardea purpurea), European nightjar (Caprimulgus europaeus), grey wagtail (Motacilla ¢inerea) and ortolan bunting (Emberiza hortulana). Two species which have until recently been regarded as stray visitors to the Seychelles, the yellow wagtail (Motacilla tiara) and tree pipit (Anthus trivialis), appear to winter regularly in small numbers on Bird Island. Other birds, such as ruff (Philomachus pugnax), pratincole (Glareola maldivarum or G. pratincola), Caspian plover (Charadrius asiaticus), cuckoo (Cuculus canorus), European roller (Coracias garrulus), hobby (Falco subbuteo) and golden oriole (Oriolus oriolus), now appear to be irregular visitors in small numbers rather than just strays, and this list may well be extended if observations can be continued over a number of years, as indeed may the list of strays. Under the Wild Animals and Birds Protection Ordinance, 1961, all migrants, except some of the larger shorebirds, are protected. This legislation, however, is relatively ineffective, and certain protected endemic birds and seabirds are still killed. Most of the migrants are sufficiently scarce, and also more wary than the endemic birds, to avoid human interference, but many arrive in a weak state and may fall prey to introduced predators such as rats and cats. Although the Seychelles are not important as a migration stop-over or wintering area for Palaearctic migrant bird populations, that so many species do find their way to such an isolated group of islands is of considerable interest. With the help of the owners of Bird Island, Mr & Mrs Guy Savy, records of migrant birds on this island will be kept over the forthcoming years. The future of Victoria mudflats, and of the availability of people competent to observe birds on them, is less certain, but hopefully the high ornithological interest of this area will not be entirely overlooked during considerations of developments for or associated with the growing tourist industry of the islands.
CHRISTOPHER J. FEARE,
Culterty Field Station, Newburgh, Ellon, Aberdeenshire AB4 0AA, Scotland
219
SRI LANKA'S GAL OYA NATIONAL PARK: ASPECTS AND PROSPECTS
Of the four wildlife national parks in Sri Lanka (Ceylon) (Crusz, 1973), the Gal Oya National Park holds out the greatest variety of prospects. It was proclaimed in 1954, less than three years after Sri Lanka's largest man-made lake, the Gal Oya reservoir (Senanayake Samudra), was formed through the damming of the Gal Oya (river) at Inginiyagala. It covers an area of 100 square miles (259sqkm), skirting the periphery of the star-shaped reservoir of which it forms part of the catchment area (Fig. 1). What little access there is to it is by boat or by jeep roads. The reservoir itself (36 square miles = 93 sq km) was declared a wildlife Sanctuary at the same time (Fig. 2). The Park consists mainly of damanas (parklands or savannas), with scattered belts of high forest close to rivers and streams and persisting as patches on the slopes of the western foothills. It is very undulating, and the smaller watercourses running across it, though bone-dry for most of the year, carry an enormous flow during the North-East Monsoon. The three main rivers (Balabedde Oya, Gal Oya, and Sellaka Oya) that flow into the reservoir pass through the Park. The famous Danigala range of hills, closely associated with the Sitala Vanniya aboriginal Veddahs, runs due north-south and falls within the Park. Large rock outcrops (inselbergs), stud the landscape constituting dramatic profiles, and there are also several caves, which until recent times were used by the Henebedde Veddahs as one of their strongholds, though such aboriginal peoples have now almost disappeared. Ancient ruins are also found within the Park. The soil is mostly rocky or gravelly and very shallow, being therefore of very poor water-storage capacity and agricultural usefulness. During the greater part of the drought season the whole area is dry except for the perennial streams. With their vast expanse of tall grass and scattered trees of all types and shapes, the damanas provide a beautiful landscape. The grasses, which are mostly illuk (lmperata cylindrica) and mana (Cymbopogon confertiflorus), grow to a height of over 5 ft (1.5 m) at the end of the North-East Monsoon season. It is well-nigh impossible to get through them then, as they are not only tall but matted together. In certain lowlying areas (dopaths) there are shorter grasses, mainly Cynodon dactylon, Ischaemum ciliare, and Aristida setacea. When the damanas are burnt, through human activity or lightning, they become talawas in which the fire-resistant trees survive. Several types of trees are found in damanas, the dominant ones being the