W Etland Birds in Turks and Caicos Islands I: a Search for W Est Indian Whistling-Ducks D E N D R O C Y G N a a R B O R Ea
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W est Indian Whistling-ducks in Turks and Caicos I 17 W etland birds in Turks and Caicos Islands I: a search for W est Indian Whistling-ducks D e n d r o c y g n a a r b o r ea Geoff M. Hilton1,Tim Cleeves2,Tony Murray3, Baz Hughes4 and Ethlyn Gibbs W illiams5 Wildfowl & Wetlands Trust, Slimbridge, Gloucestershire GL2 7BT, U.K. Current address: Royal Society for the Protection of Birds.The Lodge, Sandy, Bedfordshire SG 19 2DL, U.K. Email: [email protected] 2 Royal Society for the Protection of Birds, N orthW est England Office,Westleigh Mews, Wakefield Road, Denby Dale, Huddersfield, West Yorkshire HD8 8QD, U.K. Email: [email protected] 3 Royal Society for the Protection of Birds.The Lodge, Sandy, Bedfordshire SG 19 2DL, U.K. Current address: National Parks and Wildlife Service, Lagduff More, Ballycroy, Mayo, Ireland. Email: [email protected] 4 Wildfowl & Wetlands Trust, Slimbridge, Gloucestershire GL2 7BT, U.K. Email: [email protected] ! National Trust of the Turks & Caicos, Providenciales,Turks & Caicos, British W est Indies. Email: [email protected] The West Indian Whistling-duck (Dendrocygna arborea) is globally threatened due to significant population declines during the Twentieth Century. Turks and Caicos is a potentially important range-state for the species, but its status there has never been firmly established. A survey of West Indian Whistling-ducks was conducted in the Turks and Caicos islands during February and March 1999 to make a preliminary assessment of the distribution and abundance of the species in the territory, and to test the viability of several different survey methods, including aerial surveys, tape- playback of the species' calls, and running transects through different habitat types. Only three-five West Indian Whistling-ducks were recorded at two sites on East Caicos suggesting the species may be genuinely scarce on the islands, overlooked, or seasonally absent. The possibility that West Indian Whistling-ducks behave as somewhat nomadic opportunists in response to unpredictable changes in wetland conditions is raised. Key Words: Black-billed Whistling-duck, Caribbean wetlands, survey methods, UK Overseas Territories;. ©Wildfowl & Wetlands Trust Wildfowl (2000) 51: I 17-126 I 18 W est Indian Whistling-ducks in Turks and Caicos The W est Indian Whistling-duck large areas of undisturbed wetland habitat, Dendrocygna arborea was once widespread and few wetlands have been drained or in the Caribbean region. Its populations substantially altered. Human population have declined drastically during the last densities are very low outside the two century due mainly to habitat loss and more developed islands of Providenciales hunting, and it has been designated and Grand Turk, and two of the largest globally Vulnerable (Collar et al. 1994), islands - West Caicos and East Caicos - are although no detailed past or present uninhabited (Figure I). population estimates are available (Collar Despite this apparently high habitat et al. 1992, 1994; Rose & Scott 1997). A availability, there are very few published large population possibly persists in Cuba, records of W est Indian Whistling-ducks though there are no published population from the territory. A 1930 expedition estimates, while Cayman Islands, Bahamas, reported the species on Stubbs Cay, Fort Jamaica, Dominican Republic, Antigua & George Cay & Grand Turk (Walsh- Barbuda and Puerto Rico hold smaller McGehee et al. 1998). In 1987 there were numbers (Collar et al. 1994). records from North Caicos of 15 birds on The Turks and Caicos Islands have Bellfield Landing Pond and I I birds on generally been considered to be a part of Sawgrass Pond, in July and September the species’ range (e.g. Collar et al. 1992) respectively (Walsh-McGehee et al.. 1998). and the territory could potentially be a In 1989 a flock of ca. 20 birds, including key range-state because there are very immatures was seen at Big Pond, North r 25km 72.00W ' 22.00N North Caicos G rand Turk F Figure I . Map of the Turks and Caicos Islands W est Indian Whistling-ducks in Turks and Caicos I 19 Caicos, with two at Bellfield Landing Pond, Methods and two near Conch Bar, Middle Caicos (P. Bradley pers. comm.). In 1997 a pair with Fieldwork was conducted between 24 downy young was seen on a pond on February and 4 April 1999. This coincided Middle Caicos on 2 December (Walsh- with the dry season in the territory, which McGehee et al. 1998). This is the only in this year produced an unusually intense known breeding record for the Territory. drought such that many lagoons were In October 1998 two birds were seen on partially or completely dry.The work was Montpelier Pond, Middle Caicos conducted on five islands: Providenciales, (Pienkowski & Cross unpublished 1999). W est Caicos, North Caicos, Middle Caicos There is a need to determine the and East Caicos. South Caicos, Grand Turk distribution and abundance ofW est Indian and the smaller cays were not visited (see Whistling-ducks in Turks and Caicos, in Figure I). Five different techniques were order to give a clearer picture of the global used to survey whistling-ducks: look-see status of the species, as well as directing counts at lagoons at dawn and dusk, aerial conservation actions and protected area survey, transect counts through salt flats designation within the territory. Such work and mangroves, dusk counts on flight lines is particularly relevant at present because between mangroves and lagoons, and plans have been published for a major interviews with local people.Tape playback cruise-liner development on the pristine of the species’ distinctive call was used in wetland island of East Caicos (Anon. order to elicit a call response from unseen 1998). This paper reports on a search for birds. W est Indian Whistling-ducks in the Turks and Caicos conducted in 1999.There were Study Sites two aims: firstly to determine the distribution and abundance of the species North, Middle and East Caicos have rather in the territory, and secondly to evaluate a similar habitat characteristics. The number of different survey methods. northern (Atlantic) coasts are rocky or Habitat use by W est Indian Whistling- sandy beaches with substantial wave ducks appears to vary between different action. A band of xerophytic scrub on low parts of the species’ range; birds generally limestone ridges runs inland from the feed at night, and roost during the day (del Atlantic coast towards the southern Hoyo et al. 1992). In the Bahamas the main (Caribbean) side of the islands. Within the feeding areas were fresh or saline lagoons scrub zone are a number of brackish or within scrub (Staus 1998a, 1998b). Birds saline lagoons (known locally as ponds). also fed on intertidal flats, on fruits in the Most of these are landlocked, though some crowns of Royal Palms Roystonea sp. and in have narrow sea inlets or subterranean agricultural crops (particularly corn). connections to the sea. Mangroves Roosting sites have been found in (Rhizophora mangle, Laguncularia racemosa mangroves, around lagoons, or in dry scrub and Avicennia germinans) fringe the lagoons (del Hoyo et al. 1992; Staus 1998a). Turks and xerophytic scrub Mangroves in the and Caicos holds all of these habitat types. territory are typically poorly developed, seldom exceeding 4 m in height. The lagoons are shallow - water depths very rarely exceeded I m during this visit - with 120 W est Indian Whistling-ducks in Turks and Caicos Table I. Numbers of lagoons and survey coverage during W est Indian Whistling-duck surveys in Turks and Caicos, February-April 1999. Island Number of Lagoons Number visited at Number visited present' dawn/dusk2 but dry West Caicos 14 3 0 South Caicos 2 0 0 Middle Caicos 26 8 1 North Caicos 13 9 4 East Caicos 29 1 1 1 Providenciales 16 10 1 Grand Turk 7 0 0 Larger Cays 13 0 0 TO TAL 120 41 7 1 Estimated from 1:25,000 maps of the territory 2 Includes only sites holding water, where a wetland bird census was carried out little or no emergent or submerged were completely dry), representing vegetation. Substrates are mostly silt or approximately 33% of the total number of clay, occasionally of bare limestone. Moving lagoons in the Turks and Caicos (according towards the southern side of the islands, to 1:25,000 scale maps of the territory) the land gets lower, until the scrub is (Table I) .The aim was to locate as many replaced by extensive salt flats, which run sites as possible where the species was to the Caribbean shore.The salt flats have present, and thus to derive a minimum isolated scrub outcrops and large areas of estimate of the size of the population in shallow unvegetated water. Fringing the the territory, as well as determining its Caribbean shore are further poorly distribution. Therefore preferentially developed patches of mangroves, in selected site were apparently suitable for general no more than two metres in Whistling-ducks (e.g. larger sites with good height. W est Caicos and Providenciales habitat, sites with historical or anecdotal contain the same habitat types, but lack records of the species). O f the named extensive salt flats. ponds with historical records of the species, Bellfield Landing Pond and Dawn/dusk surveys at lagoons Sawgrass Pond (North Caicos) were Forty one lagoons were surveyed at dawn visited but were dry; Big Pond (North or dusk (a further seven were visited but Caicos) and Montpelier Pond (Middle Caicos) were surveyed. W est Indian Whistling-ducks in Turks and Caicos 121 On dawn surveys observers arrived at accessibility. No dedicated transects in sites ca. 30 minutes before sunrise, at xerophytic scrub were conducted.