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Home , Diego Garcia, Egmont Islands, Great Chagos Bank, Nelsons Island, Peros Banhos

Important Bird Areas The British Territory Peter Carr

Abstract The , which has been known as the British Indian Ocean Territory since 1965, holds 18 species of breeding seabirds, many of them in internationally important numbers. The entire area, with the exception of and its immediate surrounding waters, was designated a (MPA) in 2010, the largest MPA declared in the world so far. This UK Overseas Territory also hosts a Ramsar site based upon Diego Garcia, as well as ten Important Bird Areas (IBAs). Recent research has shown that a further two sites deserve IBA status. All of these sites have been designated IBAs for their breeding numbers or congregations of seabirds. There is a paucity of landbirds and no endemics. Human influence on the avian populations of the archipelago has been catastrophic. There is evidence of immense seabird colonies at one time but these had all disappeared by the late nineteenth century. Introduced Black Rats Rattus rattus continue to suppress numbers of breeding birds in most of the archipelago, while conversion of native forests to Cocos nucifera plantations has deleteriously altered the terrestrial environment of most islands. There is evidence that a small recovery of breeding seabird numbers is taking place on some islands, though much more research is needed. Returning many of the islands to a rat-free, coconut- managed state, which could assist seabird recovery, is a matter of funding and political will, rather than a ‘green dream’.

ying at the southern end of the –– LChagos ridge and approxi- mately in the centre of the Indian Ocean, over 2,000 km from Africa, Indonesia and mainland Asia, are the five of the Chagos Archipelago. Comprising some 55 islands, they are found between 05°15’S to 07°27’S (240 km, north to south) and 71°15’E to 72°30’E (140 km east Fig. 1. The British Indian Ocean Territory. to west). The archipelago has the Great Chagos

642 © British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory

Bank at its centre, the world’s largest . This Banhos are 3,751 mm/year and 3,999 mm/ is mostly underwater, though there are seven year respectively. falls mainly between islands on its western rim and one on October and April, when the winds are light the northern edge. To the north of the Great to moderate and generally from the north- Chagos Bank lie the atolls of and west. Between December and February, the Salomon; to the southwest is Egmont; and to Inter-Tropical Convergence Zone (ITCZ) is the south the largest island, and the only over or just south of Chagos, before it moves inhabited atoll, that of Diego Garcia. Young in north. For the rest of the year, the southeast geological terms, being some 2,000–5,000 years trades blow strongly and there is less rain old (Topp & Sheppard 1999), and low-lying during this period. The low latitude of (the vast majority of all islands bar Diego Chagos means that developing tropical Garcia are below 3 m above ), the Ter- cyclones are weak, the maximum wind speed ritory extends over a total area of around recorded being a peak gust of 120 km/hr in 60,000 km2, yet only a tiny fraction of this, 1984 (Topp & Sheppard 1999). about 60 km2, appears above the surface of the ocean (Eisenhauer et al. 1999). A brief history of the British Indian Ocean Territory Climate The Chagos Archipelago was thought to have The Chagos Archipelago has a typical trop- been first discovered by a Portuguese captain ical maritime climate. The average tempera- named Pedro Mascarenhas in 1512, but the ture on Diego Garcia is 27°C and the average initial settlers were French and landed on maximum and minimum are 29°C and 25°C Diego Garcia around 1785. They were dis- respectively (FCO 1993). The average rainfall placed by a British East Company on Diego Garcia is 2,599 mm/year, but the colonising expedition in April 1786. This northern atolls are the wettest in the Indian venture was short-lived and by October of Ocean – the averages on Salomon and Peros the same year the expedition departed, to be Andy Williams Andy 345. North Brother, one of the IBAs of the British Indian Ocean Territory, in July 2009. This unusual island has cliffs of up to 5 m high and holds breeding populations of both Audubon’s Puffinus lherminieri and Wedge-tailed Shearwaters P. pacificus, as well as 650 pairs of Brown Booby Sula leucogaster during the most recent survey, in July/August 2009. The BIOT Patrol Vessel can be seen offshore.

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ownership of the archipelago changed hands, coconut-plan- tation life continued, pros- pered and expanded out to all the other atolls of the archi- pelago from its initial base on Diego Garcia. This industry eventually declined in the Chagos in the 1900s, probably because of the competition from palm oil that was grown Janet Prushansky on the mainland at lower 346. Resurgent Island, July 2009. costs. replaced later that decade by lepers from From 1814, the archipelago was adminis- , who were marooned on the island tered from Mauritius. This changed in 1965, by the French. By 1793, the French had estab- when the British Indian Ocean Territory lished a colony on Diego Garcia using an (BIOT) was formed, prior to Mauritian inde- economy based on exportation of pendence in 1968. The original BIOT to Mauritius, these being harvested by a included the Chagos, Aldabra, Desroches and labour force of slaves originating from East Farquhar Archipelagos. However, Aldabra, Africa and . The British captured Desroches and Farquhar became part of the Mauritius and Réunion in 1810, during the Republic of when it became inde- . Under the Treaty of Paris pendent in 1976. The Chagos remained as in 1814, Réunion was restored to France, and BIOT and, following an Exchange of Notes Mauritius and its dependencies, including between the UK and the USA in 1966, all the the Seychelles and the Chagos Archipelago, islands were given over to defence purposes were ceded to Britain. While the national for an initial period of 50 years. It was announced in 1970 that a British/American communica- tions facility was to be con- structed on Diego Garcia, and this became operational in 1973 (FCO 1993). The start of construction of the military facility on Diego Garcia her- alded the removal of the last of the plantation workers, first from Diego Garcia, in 1971, and from the outer islands by 1974. Diego Garcia has been developed for military pur- poses several more times in the 40-odd years since the first construction workers landed on the island and, at the time of writing, is a full Naval Support Facility that is capable of sup- porting air-force activities. No other island in the archipelago has been developed and all Janet Prushansky 347. The Striated Heron Butorides striata is a natural colonist, have remained free of perma- which occurs throughout the British Indian Ocean Territory; nent inhabitants since at least Diego Garcia, November 2009. 1974.

644 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory

The historical impact of humans tion and export. These native trees, chiefly on the British Indian Ocean , Barringtonia asi- Territory atica, Cordia subcordata and , Very few of the islands have remained all provided nesting platforms for seabirds, unscathed by the impact of human settle- especially Red-footed Boobies Sula sula and ment. Guano was mined for fertiliser and Lesser Noddies Anous tenuirostris. They were then shipped abroad from Diego Garcia (Edis replaced by a monoculture of coconut stands 1993). These deposits probably arose from that did not offer the same breeding oppor- the terns, boobies and frigatebirds that, tunities for seabirds, because of the lack of according to the naturalist G. C. Bourne, protruding boughs and branches to provide were ‘breeding in countless numbers’ in Sep- nesting platforms. tember 1885 (Bourne 1886). The huge Only islands that were too difficult to numbers of seabirds reported by Bourne had farm for coconuts have remained relatively all but disappeared from Diego Garcia by the environmentally unscarred and, amazingly, early 1900s and the same pattern is very likely some have also remained rat-free. These to have been replicated on all the other atolls. islands – all of the The cause of catastrophic declines in islands, with the exception of the once- breeding seabirds is the familiar oceanic- inhabited Eagle Island (the second-largest island tale of unfettered harvesting of birds island in the Chagos), six islands in northeast and eggs by humans combined with the Peros Banhos, and three small islands in introduction of alien animals. In the Chagos Diego Garcia – offer a view of what the Archipelago, these consisted, at various times habitat must have looked like before the in the islands’ history, of sheep, cattle, arrival of humans. These islands are each and donkeys, together with (and having the unique, with differing vegetation zones and greatest impact on birds) , pigs, and associations. The islands that have sandy Black Rats Rattus rattus (Edis 1993). beaches generally have a beach crest of At the same time as the introduction of interspersed with Argusia alien predators came the environmental and (Tournefortia) argentea, coconut and occa- ecological traumas associated with the sionally Morinda citrifolia and Guettarda destruction of the native hardwood stands, speciosa. Inland, these islands often contain which were used for boat-building, construc- bare rock or open grassy areas, and this is Peter Peter Carr 348. Diego Garcia, August 2009.

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where Sooty Terns Onychoprion fuscatus and Islands that were inhabited or visited reg- Brown Noddies Anous stolidus still nest in ularly for coconut harvesting are generally numbers that qualify the islands for Impor- rat-infested, hold few large stands of native tant Bird Area (IBA) status. trees and have the highest number of invasive Some of the islands that were not inhab- plants and insects. Diego Garcia, the largest ited also have stands of grand native hard- island in the Chagos, with the longest history woods and these still provide nesting of human presence, has by far the largest platforms for seabirds. The Pisonia grandis number of invasive species. stands on Petite Ile Bois Mangue hold up to 12,000 pairs of breeding Lesser Noddies and Bird recording in the British Indian the same species of tree regularly holds over Ocean Territory 10,000 pairs of seabirds on North Brother. In The recording of birds from the Chagos Peros Banhos, the island of Grand Coquillage Archipelago has been sporadic. The first pub- has the unusually symmetrical-limbed tree lished records appear to be by G. C. Bourne, Neisoperma () oppositifolia and these a naturalist who visited the islands in 1885 provide nesting platforms for thousands of (Bourne 1886). The Percy Sladen Expedition Lesser Noddies and, in recent years, Great of 1906 (Gadow & Gardiner 1907) produced Frigatebirds Fregata minor. bird records from all of the atolls, but there- after came a dearth of records that lasted until the 1970s. The majority of records during this quiet period were from visiting mariners and most were published in Sea Swallow, the journal of the Royal Naval Birdwatching Society. Bill Bourne collated all bird records up to 1971 from the Chagos Archipelago and Peter Peter Carr 349. Lesser Noddies Anous tenuirostris breed in the British Indian Ocean surrounding seas Territory in their thousands and are one of the reasons for IBA status for and published a ten designated and two proposed islands; Peros Banhos, February 2010. summary in his Andy Williams Andy 350. The IBA of Ile Parasol, in Peros Banhos, July 2009; a ‘typical’ BIOT island.

646 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory Roger Roger Dickey 351. Creche of Red-footed Boobies Sula sula, Diego Garcia, November 2007. 1971 analysis of the birds of the area (Bourne author has been working on Diego Garcia, 1971), undertaken as part of the study of the and up to late 2010 had access to the outer ecology of the Territory prior to the building atolls, including as a member of the 2010 sci- of the military facility on Diego Garcia. This entific expedition. The seabird counts of 1996 seminal work remains the broadest-ranging and 2006 have now been repeated at different ornithological analysis of the archipelago times of the year between 2008 and 2010 and undertaken to date. a slightly better understanding of the seabird Since 1971, there has been an increase in breeding strategies is now available. the number of visiting ornithologists, though An internet-based database (www. the archipelago remains woefully under- worldbirds.org) holds details of every species researched, particularly in terms of its inter- that is considered to have been positively nationally important breeding seabird recorded in the Chagos Archipelago and the populations. During the 1970s, there were a surrounding seas, including those that were series of Joint Service Expeditions that introduced or ship-assisted, as well as those focused primarily on the underwater envir - which have occurred naturally. This website onment but also gathered ornithological is presently the archive for ornithological records that assisted in the identification of data and should be the repository of any ten existing IBAs (BirdLife International future records from the Territory. 2004; Carr 2006). Two visiting scientific expe- ditions produced the first methodical cen- The birds of the British Indian suses of the breeding seabirds. The first, in Ocean Territory 1996, provided an excellent baseline of The birds of the Chagos Archipelago fall nat- breeding seabird data (Symens 1999) and was urally into three groups: the resident land- also a major source of data for the selection birds, the migrants and vagrants, and the of IBAs. The second, in 2006, repeated the seabirds. Of the first group, there are many seabird counts of the 1996 expedition and factors that contribute to a paucity of land- recommended a further two islands for IBA birds: the islands are isolated and truly status (McGowan et al. 2008). Since 2008, the oceanic (in that they have never been linked

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to a continental land mass); they are young in and Striated Heron Butorides striata (which geological terms; and they also lack any sig- has colonised all of the atolls). The remaining nificant altitudinal difference. Only three res- resident landbirds have all been introduced, ident landbirds are believed to have arrived as as pets, food or attempts at biological natural colonists: Common Moorhen control. The species involved are Red Jungle- Gallinula chloropus and White-breasted fowl (domestic chickens) Gallus gallus, Cattle Waterhen Amaurornis phoenicurus (which Egret Bubulcus ibis, Madagascan Turtle Dove have, to date, settled on Diego Garcia only), Nesoenas picturata, Geopelia striata, Madagascar Red Fody Foudia madagas- cariensis and Acridotheres tristis (Hutson 1975; Lever 1987). All are now restricted to Diego Garcia except the fody, which is found on every island large enough to hold seeds for food. Populations of House Sparrow Passer domesticus once existed on Peros Banhos and Salomon (Lever 1987) but are now thought to be extinct. Bourne (1971) sug- gested that landbirds could arrive on Diego Garcia

Janet Prushansky from three directions: 352. Cattle Egrets Egretta garzetta were introduced in the 1950s west, north and east. While to Diego Garcia; today, they still breed only on Diego Garcia but it appears that most of the are occasionally seen on other atolls; September 2009. regular migrants are from northern latitudes, there is some evidence suggesting that the vagrants to the islands do come from all three directions. The only regular migrants that occur in any numbers are shorebirds. Turnstones Arenaria interpres and Curlew Sandpipers Calidris ferruginea are the most numerous and wide- spread, with wintering birds numbering in the low thousands. Whimbrel Numenius phaeopus and Common Greenshank Tringa nebularia are also Chris Patrick 353. The Madagascar Red Fody Foudia madagascariensis is widespread species, with introduced and is the only passerine found throughout all the atolls wintering populations of the British Indian Ocean Territory; Diego Garcia, November 2007. probably of less than a

648 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory thousand in total. Several other shorebirds are annual in the northern winter in small numbers, often fewer than ten individuals, and are usually associated with artificial wetlands on Diego Garcia: Sanderling Calidris alba, Little Stint C. minuta, Terek Sand- piper Xenus cinereus, Common Sandpiper Actitis hypoleucos and Wood Sandpiper Tringa glareola. Vagrants comprise a substantial part of the list of 116 species of bird recorded with certainty in the Territory and most rarities have occurred in October and November. The bulk of the vagrants are shorebirds, with species such as Eurasian Curlew N. arquata and Marsh Sandpiper T. stagnatilis probably coming from the north. Others, such as Red-necked Stint C. ruficollis, Long-toed Stint C. subminuta and Andy Williams Andy Sharp-tailed Sandpiper C. acumi- 354. Sooty Tern Onychoprion fuscatus on Petite Ile Coquillage nata, may have had an easterly in July 2009. This is the most numerous breeding seabird in arrival direction; these three the British Indian Ocean Territory, though much has still to species were all present and pho- be learnt about its breeding regimes. tographed on a single small pond on Diego The arrival of both species in the archipelago Garcia in November 2009, along with a Red- coincides with the normal arrival dates of the necked Phalarope Phalaropus lobatus. The highly migratory Globe Skimmer Pantala one vagrant that may have arrived from a flavescens, the dragonfly species that the birds westerly direction is a claimed Dimorphic are thought to be following (Anderson 2009). Egret Egretta dimorpha, this species having Seabirds are present in globally important the majority of its population based in numbers, resulting in the current designation Comoros, Kenya, Madagascar Mayotte, of ten IBAs (and two proposed IBAs). To Seychelles and , all west of BIOT. date, 18 species are known to have bred (see Other species of interest to have occurred Appendix 1). Some, such as Roseate Tern as vagrants include both Yellow Motacilla Sterna dougallii and Bridled Tern flava subsp. and Grey Wagtail M. cinerea, the Onychoprion anaethetus, breed in small only true passerines to have been recorded. numbers – fewer than 15 pairs annually – Hoopoe Upupa epops and Osprey Pandion while others, such as Red-footed Booby, haliaetus have put in single one-day appear- Sooty Tern, and , ances. Other records of interest include a are breeding in internationally important single juvenile European Roller Coracias gar- numbers. rulus in November 2009 and the near-annual Much has still to be learnt about the appearance of Amur Falcons Falco amurensis, seabird breeding populations of BIOT. The the majority of sightings in November. Both two seabird censuses carried out as part of European Rollers and Amur Falcons are the scientific expeditions in 1996 and 2006 known to migrate from southeast Asia across were both undertaken in February and the western Indian Ocean to winter in Mada- March and were assumed to be representative gascar and East Africa, probably following counts of the entire breeding populations. migrating swarms of dragonflies (Odonata). Subsequent research, in 2008 and 2010, when

British Birds 104 • November 2011 • 642–659 649 Carr – 80 breeding 2 Red-footed Booby – the figure of – the figure Booby 16,067 Red-footed Updated information Updated as qualifying be criteria to is believed erroneous and likely nearer 4,000. There There 4,000. nearer and likely erroneous mainland on pairs 3,530 breeding were 2011. in March Diego Garcia Brown Noddy did not breed terrestrially did not breed Noddy Brown 2008 and October masse between en pairs – 3,500 breeding Booby Red-footed in February 2010. leucogaster Sula Booby Brown pairs in May 2010. in May pairs 2010. pairs Shearwater – 200 breeding Audubon’s 2008. in November 2009. in July/August in pairs – 10,000 breeding Sooty Tern 2009. May/August February 2010. 1 Anous stolidus Anous (16,067 breeding pairs) (16,067 breeding Key species when qualifying Key More than 10,000 pairs of than 10,000 pairs seabirds More at this site. regularly occur (11,100 breeding pairs) (11,100 breeding pairs) (3,470 breeding Booby Red-footed occur than 20,000 waterbirds More at this site. regularly 2010. October More than 20,000 waterbirds occur regularly regularly occur than 20,000 waterbirds More at this site. 2008 and October October masse between pairs) (420 breeding of than 10,000 pairs occur seabirds More at this site. regularly pairs – 650 breeding Booby Brown pairs) (12,500 breeding of than 10,000 pairs occur seabirds More at this site. regularly in pairs – 10,500 breeding Sooty Tern . (2008). et. al McGowan data from 3 qualifying criteria IBA A4i; A4ii; A4iii A4ii; A4i; Noddy Brown A4i; A4iii A4i; pairs) (11,500 breeding Noddy Brown terrestrially en did not breed Noddy Brown A4ii; A4iii A4ii; lherminieri Shearwater Puffinus Audubon’s A4iii A4i; fuscatus Onychoprion Sooty Tern data from Carr unpubl.; Carr unpubl.; data from 2 data from Carr (2006); Carr (2006); data from Diego Garcia (including East, (including Diego Garcia Middle & West Island) West & Middle 1 The Important Bird Areas of the British Indian Ocean Territory, with updated information where available. where with updated information Territory, of the British Indian Ocean Areas The Important Bird IO001 IO001 reserve, nature Barton Point A4iii A4ii; sula Sula Booby Red-footed Table 1. Table IBA; a proposed * denotes Key: CodeIBA Group IBA Present Present Proposed name Site IO002 IO002 Island Danger IO003 IO002 Sea Cow IO004 IO002IO005 Brother North IO002 Brother Middle

650 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory . 2,000 breeding pairs in June 2009. in June pairs 2,000 breeding . . 10,000 breeding pairs in May 2009, in May pairs 10,000 breeding . 3 3 Sooty Tern – 10,000 breeding pairs in May 2009, in May pairs – 10,000 breeding Sooty Tern in February pairs breeding 2010. in pairs – 10,000 breeding Sooty Tern Lesser Noddy – 10,000 breeding pairs in pairs – 10,000 breeding Noddy Lesser 2009. July/August terrestrially en did not breed Noddy Brown 2010. October in July pairs – 1,000 breeding Noddy Lesser in February pairs 1,400 breeding 2010 2009. present. and 10,000 birds terrestrially en did not breed Noddy Brown 2010. 2008 and October October masse between in March pairs – 20,424 breeding Sooty Tern increased to 15,000 by July 2009. 31,250 2009. July 15,000 by to increased in February pairs breeding 2010. 2009. in July pairs – 20,000 breeding Sooty Tern Lesser Noddy – 10,000 breeding pairs in pairs – 10,000 breeding Noddy Lesser February 2009 and 2010. in March pairs – 9,186 breeding Sooty Tern More than 20,000 waterbirds occur regularly regularly occur than 20,000 waterbirds More at this site. 10,000 2009. July 20,000 by to increasing regularly occur than 20,000 waterbirds More at this site. 2008. November (7,300 breeding pairs) (7,300 breeding pairs) (6,100 breeding Noddy Brown regularly occur than 20,000 waterbirds More at this site. 2008 and October masse between pairs) (8,300 breeding Noddy Brown occur than 20,000 waterbirds More at this site. regularly regularly occur than 20,000 waterbirds More 2006 regularly at this site. regularly of than 10,000 pairs occur seabirds More at this site. regularly at this site. of than 10,000 pairs occur seabirds More 2006 A4i; A4iii A4i; tenuirostris Anous Noddy Lesser A4iii A4i; pairs) (13,700 breeding Noddy Lesser A4i; A4iii A4i; pairs) (32,000 breeding Sooty Tern A4i; A4iii A4i; pairs) (14,000 breeding Sooty Tern (IO004) Ile Coquillage* Petite (IO004)A4iii A4i; Ile Grande Coquillage* pairs) (34,669 breeding Sooty Tern A4iii A4i; pairs) (15,429 breeding Sooty Tern The Important Bird Areas of the British Indian Ocean Territory, with updated information where available. ( continued ) available. where with updated information Territory, of the British Indian Ocean Areas The Important Bird IO007 IO003IO008 Nelson IO004 Ile Bois Mangue Petite A4iii A4i; pairs) (12,000 breeding Noddy Lesser Table 1. Table IO006 IO002 Brother South IO010 IO004 Ile Longue IO009 IO004 Ile Parasol

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breeding pattern. The breeding fre- quency of the Sooty Tern is not yet known for certain, nor whether it nests on the same islands in every breeding period or, as it appears, sometimes fails to breed on certain islands. Similar questions surround the Lesser Noddy; a tentative hypothesis is that there are three separate populations, one centred on the

Lisa Kedding western Great Chagos 355. Great Frigatebirds Fregata minor have increased on a number of the Bank islands, one on British Indian Ocean Territory islands in response to conservation efforts, Nelson’s Island on the including Grande Ile Coquillage, where this nest was photographed, in northern rim of the August 2009. Bank, and a third repeated counts were made of the seabird centred on the islands in the northeast of populations during other months, revealed Peros Banhos, with the three populations that for some species, such as Brown Booby breeding at different times. Sula leucogaster, February and March is not There is evidence that Red-footed Booby the peak breeding period (in 2009, August at least is increasing in both numbers and produced the highest breeding numbers of range, and this is probably due to the reduc- this species). Other species, such as Red- tion of human interference. For example, on footed Booby and both noddies, breed con- Diego Garcia there were fewer than ten pairs tinuously throughout the year, with peaks in nesting on the mainland in 1985. Since that breeding numbers between January and April year, when the eastern arm of the island was for the booby. The data for the two noddies is declared a Conservation (Restricted) Area not yet sufficient to interpret a consistent and placed out of bounds, breeding numbers Peter Peter Carr 356. The southern barachois, Diego Garcia, August 2009.

652 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory have increased steadily and there are now over 5,000 pairs nesting per annum. Similar increases in numbers and expansion of ranges have been witnessed in all the other BIOT atolls. Similar but less spectacular increases in range and numbers have been found for the kleptoparasitic Great and Lesser Frigatebirds Fregata ariel. In terms of non-breeding seabirds, 22 species had been reported by 1971 (Bourne 1971) and by 2009 this figure had risen to 37. This increase is presumed to be a result of greater recording effort and better optics and field guides, rather than a genuine increase in the number of seabird species present or passing through.

Sites of global importance for biodiversity in the British Indian Ocean Territory There are presently three categories of sites of Fig. 2. Diego Garcia Ramsar site. Figure global importance for biodiversity in BIOT; extracted from Diego Garcia Integrated these consist of a single IUCN (International Natural Resources Management Plan and Union for the Conservation of Nature) - amended. egory 1 No-Take Marine Protected Area (MPA); a Ramsar site and ten IUCN Impor- throughout the Chagos Islands. While the full tant Bird Areas (IBAs). implications and management details of the Following public consultation, the desig- MPA are still to be finalised, the prospects for nation of a strict No-Take Marine Protected both terrestrial and marine ecosystems and Area (in an announcement of the UK Gov- their research must be enhanced. ernment on 1st April 2010), covering the There is a single Ramsar site, based upon whole of BIOT and its seas (though Diego Garcia. Designated in July 2001, it excluding Diego Garcia and the seas out to covers 35,424 ha and extends over the three nautical miles, or 5.56 km, around this eastern, uninhabited, arm of the island, the atoll) and thus approximately 550,000 km2, entire lagoon (with the unexplained excep- created the largest marine reserve in the tion of the southern barachois), the three world. Tuna-fishing licences stopped being islets in the mouth of the lagoon and seas issued by the UK Foreign & Commonwealth ocean-side of the eastern arm out to three Office in October 2010 (www.fco.gov.uk nautical miles (see fig. 2). ‘The site qualifies accessed 26th June 2011). for the [Ramsar] List under 7 of the 8 The enforcement of this no-take policy is Ramsar Criteria and is a particularly good undertaken by the BIOT Patrol Vessel, often accompanied by members of the British mili- tary contingent on Diego Garcia. The BIOT islands as well as its seas are patrolled, since illegal harvesting is not limited to the seas. Historically, islands have been used as a base for maritime poachers, who probably affect breeding seabirds as well as IUCN endan- gered species such as Hawksbill Turtle Eretmochelys imbricate and Green Turtle Che-

lonia mydas and the unique www.zianet.com/tedmorris/dg Birgus latro, all of which are found 357. Diego Garcia from the air.

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example of a relatively unpolluted system in a near-natural state, of special value for maintaining the genetic and ecolog- ical diversity of the region, especially its marine life’ (www.ramsar.org accessed 27th June 2011). From a terrestrial aspect, contributing factors to the Ramsar designation were the breeding populations of the two endangered turtles and Coconut Crab (see above), which fulfil Criteria 2. (Subsequent to the Ramsar designation, it has been discovered that this site holds approximately 294 Coconut Crabs per hectare, the highest density ever recorded anywhere. It is thought that this population density exists because of the lack of har- vesting; Vogt 2011.) From an avian perspec- tive, the eastern arm and three islets in the mouth of the lagoon of Diego Garcia regu- larly hold more than 20,000 waterbirds and Fig. 3. Important Bird Areas (IBAs), Strict this fulfils Criteria 5 of the Ramsar require- Nature Reserves (SNRs) and Diego Garcia ments. The most abundant waterbird here is Conservation (Restricted) Area in the British the Red-footed Booby and its numbers (over Indian Ocean Territory. 3,500 pairs) also qualify this site as an IBA. At present there are ten designated IBAs Key to fig. 3. All numbered islands are Strict Nature Reserves, (BirdLife International 2004; Carr 2006) and with the exception of Diego Garcia, which has a two proposed IBAs (McGowan et al. 2008), designated Conservation (Restricted) Area. though the true situation concerning IBAs Islands that are also Important Bird Areas are may not be quite as clear-cut as this. The annotated. 2006 census of seabird populations, under- Diego Garcia Conservation (Restricted) taken in February and March, revealed that Area the IBA qualifying criteria for some (desig- 1. Barton Point nature reserveR including EastRF, nated) islands was not met during that MiddleRF & West IslandRF(IBA) The Great Chagos Bank survey period, but that populations on two 2. Danger Island (IBA)RF other islands did meet the criteria (McGowan 3. Sea Cow (IBA)RF et al. 2008). Further survey work between 4. South Brother (IBA)RF October 2008 and October 2010 showed that 5. ResurgentRF 6. Middle Brother (IBA)RF some seabirds, including the IBA qualifying 7. North Brother (IBA)RF species of Brown and Lesser Noddy, Sooty 8. Nelson’s Island (IBA)RF Tern and Red-footed Booby, do not neces- Peros Banhos sarily breed annually, synchronously or on 9. Ile Parasol (IBA)RP 10. Ile Longue (IBA)RP the same islands, season after season (pers. 11. Petite Ile Bois Mangue (IBA)RP obs.). Table 1 summarises the designated and 12. Grande Ile Bois MangueRP proposed IBAs, their qualifying criteria and 13. Ile ManöelR updated information as known at present. 14. Ile YéyéR 15. Petite Ile CoquillageRP From a conservation perspective, it may 16. Grande Ile CoquillageRP be wiser to adopt a ‘landscape-level’ approach 17. Coin du MireRF to IBA designation in the Chagos. ‘Such 18. Ile Vache MarineR approaches typically involve the identifica- R = rats definitely present tion and integration into broader socio-polit- RP = rats possibly present ical agendas of inter-connected networks of RF = rat free core areas, linked by habitat corridors, pro- (Rat data from Carr, unpublished.) tected by buffer zones and, in some cases,

654 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory further developed by restoration areas’ breeding, populations from the ‘designated’ (BirdLife International 2004). This is particu- IBA’s could, hypothetically, spread and larly relevant to the seabirds of the Chagos, increase onto these islands in due course. where the breeding numbers, breeding phe- This idea has already received some support nology and breeding distribution are still not in the Chagos since 2006, when a rat eradica- truly known or understood. Fig. 3 shows the tion project on Eagle Island, on the western IBAs, Strict Nature Reserves (SNRs) and the Great Chagos Bank, the second-largest land single Conservation (Restricted) Area in the mass in the archipelago and in the midst of Chagos. five designated IBAs, was unsuccessful An alternative strategy to IBA designation (Daltry et al. 2007). in the Chagos would be to cluster the ten des- All of the IBAs are also SNRs or, in the ignated and two proposed IBAs into four case of Barton Point and the three associated ‘grouped’ IBAs. These would consist of Diego islets in the mouth of Diego Garcia lagoon, a Garcia (1); the Western Great Chagos Bank Islands (2–7); Nelson’s Island (8) and the Eastern Peros Banhos Islands (9–18), five of which do not presently match IBA qualifying criteria. This would be consistent with IBA philosophy in desig- nating inter-connected, protected habitats for species that, with the limited data available,

appear to utilise dif- Janet Prushansky ferent islands for 358. The White-breasted Waterhen Amaurornis phoenicurus, found only breeding in different on Diego Garcia, is one of just three resident landbirds which are seasons. thought to have arrived as natural colonists; September 2010. This ‘four IBA’ concept is also amen - able to the restoration ideology of IBA protec- tion status (BirdLife International 2004). At least three of the islands in the eastern Peros Banhos group (Ile Manöel, Yéyé and Vache Marine) are infested with Black Rats; these are former coconut plantations that are now virtually sterile monocultures with little biodiversity. With resource investment to eradicate rats and Chris Patrick restore native habitat 359. Brown Noddy, another important breeding seabird of the British conducive to seabird Indian Ocean Territory; Diego Garcia, November 2007.

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Conservation (Restricted) Area. This affords Recommendations for bird them a degree of protection, both through conservation in the British Indian BIOT Law and the physical enforcement of Ocean Territory the Law. The Protection and Preservation of With the creation of the Chagos Marine Pro- Wildlife Ordinance (Ordinance No. 1) of tected Area (MPA), an opportunity now 1970 facilitates the making of Regulations exists to further our understanding of this concerning the governing of the SNRs. unique region, particularly with regard to the The SNR Regulations (1998) that came internationally important populations of into force in November 1998 designated the breeding seabirds. There is also the potential BIOT SNRs, and any individual found in opportunity to restore some of the ecologi- contravention of these regulations is liable to cally traumatised islands back to a state that up to six months’ imprisonment or a fine not would increase the habitat available for exceeding £5,000. Barton Point IBA, which breeding seabirds. Both rat eradication and includes East, Middle and West Islands, is coconut tree control have been successfully covered by the Diego Garcia Conservation achieved elsewhere on oceanic islands. With (Restricted) Area Ordinance No. 6 of 1994; sufficient funding and political will, there is infringements carry a maximum fine of no reason why, in the world’s largest MPA, £500. The SNRs (and all islands and the seas the terrestrial habitat in the Territory cannot of BIOT) are patrolled regularly by the BIOT be restored to a sufficient degree to match the Patrol Vessel that operates out of Diego pristine marine environment. Garcia. These patrols often include members In the light of recent data on seabird of the British Military Forces stationed on breeding phenology, the Important Bird Area Diego Garcia, who land and search the designation criteria for BIOT should be islands. The terrestrial patrols have the reviewed. The review should analyse whether potential to carry live arms, their main target individual islands or clusters of islands being illegal poachers, which have been should constitute an IBA. Moreover, manage- known to operate occasionally from the ment plans for the future IBAs and SNRs islands. should be drawn up as a matter of priority. Peter Peter Carr 360. The conversion of native forests to coconut Cocos nucifera plantations has had a significant and negative effect on most islands in the British Indian Ocean Territory. Clearance of coconut stands, here on Diego Garcia in September 2009, is a key element of the necessary conservation management for many of the islands.

656 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory

The focus of these plans should be the eco- consideration the proposed management logical restoration of environmentally trau- plans of all the SNRs, particularly if the matised islands. Restoration that would island-cluster IBA system is to be adopted. enhance the productivity of breeding  The prioritisation of island ecological seabirds should be prioritised, and this work restoration should be linked with IBAs, should be linked with an analysis of the IBA especially if the island-cluster IBA system designation system in BIOT – if the island- is to be adopted. cluster system is adopted, there are many islands that are prime targets for ecological The future of bird conservation in restoration work, for example those SNRs in the British Indian Ocean Territory northeastern Peros Banhos or Eagle Island. Although rats and overgrown coconut plan- The following recommendations are tations continue to be both deterrents to made: colonisation and inhibiters to rejuvenation,  Long-term monitoring of the breeding the future for the terrestrial environment of seabirds should be funded and BIOT is not necessarily bleak. On Diego standardised. Garcia, within the Barton Point IBA/SNR and Ramsar site, ecological restoration has  Management plans for all SNRs. begun. A management plan for the site is in  Management plans should focus on rat production, some mapping of vegetation eradication, removing invasive vegetation zones has occurred and at least 15 ha of and restoring indigenous flora to islands former coconut stands in three areas have that are dominated by former coconut been felled. These three areas are being plantations. managed with varying degrees of resource  A review of the IBAs. This should analyse requirement to restore natural habitat zones. whether the present individual island IBA Several important lessons have been learnt designation or grouping proximal islands about habitat restoration in BIOT and these as a single IBA is the most effective should inform the restoration process in the conservation management strategy. outer islands (Carr 2010).  The IBA review should take into In March 2010, as part of the Chagos Peter Peter Carr 361. Red-footed Boobies Sula sula are increasing in range and breeding numbers throughout the British Indian Ocean Territory; this photo shows the ongoing recolonisation of Egmont, in July 2009.

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Scientific Research Expedition, the atolls — 2010. Working towards atoll restoration. Part 2 – were surveyed with a view to identifying Barton Point Hardwood Restoration Project (Clearing the coconut chaos). Chagos News 3: 10–21. which islands most warrant ecological Daltry, J., Hillam, C., & Meier, G. 2007. Follow up visit to restoration (Clubbe & Carr in prep.). The Eagle Island, March 2007. Report to the UK Foreign initial conclusion of that research is that the & Commonwealth Office, HMG. Edis, R. 1993. Peak of Limuria: the story of Diego Garcia two islands in eastern Peros Banhos which and the Chagos Archipelago. Chagos Conservation are not SNRs, Iles Moresby and Passé, are the Trust, . highest priority. Eisenhauer, A., Heiss, G. A., Sheppard, C. R. C., & Dullo, At present, neither funding nor Foreign & W. C. 1999. Reef and island formation and late Holocene sea-level changes in the Chagos islands. Commonwealth Office formal approval has In: Sheppard, C. R. C., & Seaward, M. R. D. (eds.), been secured for ecological restoration any- Ecology of the Chagos Archipelago, Linnean Society where other than on Diego Garcia. However, Occasional Publications 2. it is hoped that the success of the work on Foreign & Commonwealth Office (FCO). 1993. British Indian Ocean Territory: the Chagos Archipelago. this atoll will inspire decision-makers to HMSO, London. allow the restoration operations elsewhere. Gadow, H., & Gardiner, J. S. 1907. The Percy Sladen The Chagos Archipelago holds internation- Expedition Trust to the Indian Ocean. Aves, with some notes on the distribution of the land-birds of ally important breeding seabird populations the Seychelles. Trans. Linn. Soc. Lond. Zool. II 12: and it is possible that, with habitat manage- 103–110. ment of islands around these populations, Hutson, A. M. 1975. Observations on the birds of they can increase in numbers and expand. In Diego Garcia, Chagos Archipelago, with notes on other vertebrates. Atoll Research Bulletin 175: 1–26. a world where many seabird populations are Lever, C. 1987. Naturalized Birds of the World. Longman, declining, a combination of sympathetic Harlow. management and political goodwill in this McGowan, A., Broderick, A. C., & Godley, B. J. 2008. Seabird Populations of the Chagos Archipelago: an unique UK Overseas Territory offers the evaluation of Important Bird Area sites. Oryx 42: opportunity to buck a depressing trend. 424–429. Symens, P. 1999. Breeding Seabirds of the Chagos References Archipelago. In: Sheppard, C. R. C., & Seaward, Ecology of the Chagos Archipelago Anderson, R. C. 2009. Do dragonflies migrate across M. R. D. (eds.), . the western Indian Ocean? J. Trop. Ecol. 25: 347–358. Linnean Society Occasional Publications 2. Linnean BirdLife International. 2004. Important Bird Areas in Asia: Society/Westbury Publishing, London. key sites for conservation. BirdLife Conservation Topp, J. M. W., & Sheppard, C. R. C. 1999. Higher Plants Series No. 13, Cambridge. of the Chagos Archipelago. In: Sheppard, C. R. C., & Ecology of the Chagos Bourne, G. C. 1886. General observations on the Seaward, M. R. D. (eds.), Archipelago fauna of Diego Garcia. Proc. Zool. Soc. Lond. 1886: . Linnean Society Occasional Publications 331–334. 2. Linnean Society/Westbury Publishing, London. Bourne, W. R. P. 1971. The Birds of the Chagos Group, Vogt, S. 2011. Population densities and demographics Birgus latro Indian Ocean. Atoll Research Bulletin 149: 175–207. of the Coconut Crab on Diego Garcia, Carr, P. 2006. British Indian Ocean Territory. In: Sanders, British Indian Ocean Territory. Unpublished report S. M. (ed.), Important Bird Areas in the United to Naval Facilities Engineering Command Far East, Kingdom Overseas Territories, pp. 37–55. RSPB, Sandy. Yokosuka, Japan.

Peter Carr, Environmental Director, DG 21, BF BIOT, Diego Garcia, British Indian Ocean Territory

Peter Carr first visited the Chagos as a Royal Marine Commando in 1996. He subsequently led three birdwatching trips to Diego Garcia between 1997 and 2007. He was stationed on Diego Garcia from October 2008 to October 2010 as the British Executive Officer, during which period he visited every island in the Territory and the IBAs up to five times. He retired from the military in 2011 and is now the Environmental Director on Diego Garcia where, in conjunction with the RSPB, he continues his interests in island ecological restoration and promoting conservation and environmental awareness throughout BIOT. Peter is the author of the recently published Guide to the Birds of the British Indian Ocean Territory (see p. 678). Many of the photographs in this paper, all of which were taken on BIOT, are also featured in the guide, and are reproduced here with kind permission of the publisher.

658 British Birds 104 • November 2011 • 642–659 The British Indian Ocean Territory

Appendix 1. Distribution of breeding seabirds, British Indian Ocean Territory. Wedge-tailed Shearwater Wedge-tailed Shearwater Audubon’s Tropicbird White-tailed Tropicbird Red-tailed Booby Masked Booby Red-footed Booby Brown Frigatebird Great Frigatebird Lesser Tern Crested Great Tern Roseate Black-naped Tern Little Tern Bridled Tern Sooty Tern Noddy Brown Noddy Lesser Tern White Common

Diego Garcia B1 B1 Diego Garcia B BS BB B BB2 B BB East Island B BS BS BBB Middle Island BB2 BBB West Island BB1 B2 BB1 Ile Sudest complex BB BBB Ile Lubine complex BB Great Chagos Bank B1 Danger Island BBBB2 B2 B2 B BB Sea Cow BBB2 B1 B BB Eagle Island BBBB North Brother BB BBBB B BBB Middle Brother B BS B1 BBBB Resurgent B1 BB South Brother BB B B1 BBBB Nelson’s Island BB B B BBB Peros Banhos B1 B1 B2 B2 Ile du Coin BBBB Anglais BBB Monpatre B1 Poule BB Petit Soeur BB Grand Soeur BB Pierre BB Petit Mapou B Grande Mapou BB Diamant BBBB Passe BBBB Moresby BBBB Parasol BBBBB Longue BB2 BBBB Grand Bois Mangue BBBBB Petite Bois Mangue BB1 BBBB Manöel BBBB Yéyé B1 BBBBB Petite Coquillage BB BBBB Grande Coquillage BBB2 B2 BBBB Coin de Mire BBBBB Vache Marine BB BB Fouquet BB Mapou de Coin BB Salomon B2 B1 B1 B2 Boddam B BS B Diable BS BS Anglaise BBBB Passe BBBB Mapou B BS B1 BBB Takamaka B1 BBBBB Fouquet BBB Sepulture B1 Jacobin BB1 Sel B BS Poule BB1 Footnotes: B = Breeding confirmed between October 2008 and October 2010 (Carr unpubl.); BS = Breeding suspected between October 2008 and October 2010 (Carr unpubl.); B1 = Breeding confirmed in 1996 (Symens 1999); B2 = Breeding confirmed in 2006 (McGowan et al. 2008). Where one or more authors have recorded a seabird breeding on an island, only the most recent record is annotated. The following species in this appendix are not mentioned in the main text; their scientific name is thus given here: Wedge- tailed Shearwater Puffinus pacificus, White-tailed Tropicbird Phaethon , Red-tailed Tropicbird Phaethon rubricauda, Masked Booby Sula dactylatra, Black-naped Tern Sterna sumatrana, Little Tern Sternula albifrons, Common White Tern Gygis alba.

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