The increasing demand for land for housing and resort development has created pressure on wildlife habitat. One third of St. Croix is classified as “developed” (Caribbean Data Center 2003, unpubl. data), although this statistic does not take into consideration the level of fragmentation or the integrity of remaining habitat.

The wildlife of St. Croix can be described under 8 different categories:

The enormous Leatherback Turtle is the largest of the sea turtles, weighing over 600 kg with carapace lengths reaching over 180 cm. It is federally endangered (USFWS 1970). It is pan-global and capable of migrating over 4800 km. They nest on tropical and subtropical beaches, but forage areas extend to cold temperate waters off Canada and northern Europe. The leatherback is only seasonally found around St. Croix. The turtles arrive in the spring and begin to nest in March. Most of the nesting activity occurs on Sandy Point, a 3-km-long expanse of beach on the south west corner of St. Croix. Sandy Point’s broad, sandy beaches are located near the shelf edge, thereby allowing the deepdiving leatherbacks to stay in deep water right up to the beach, thus avoiding potential marine predators. They have been observed nesting on a few other beaches that are not obstructed by coral reefs. Leatherbacks feed almost exclusively on gelatinous organisms such as jellyfish, and as such are prone to ingesting floating plastic debris. The studies at Sandy Point have shown that in the USVI females nest in two- to seven-year intervals, laying an average of 5-6 clutches per season, although they can lay up to 11 clutches. Adults can dive to depths of at least 1500 m. Satellite telemetry has shown that leatherbacks often travel between islands during inter-nesting periods (www.wimarcs.org).

In the USVI the leatherback receives the bulk of attention and research funding. Almost all funding available for federally listed species in the USVI is allocated to the leatherback. Since the start of the Saving the Leatherback Turtle project at Sandy Point NWR, which follows the goals set forth in the recovery plan, the numbers of leatherback sea turtles nesting on the beach has gone from 20 per year to nearly 200 per year, with a possible doubling of hatchling emergence, with recent estimates suggesting that the population has increased over 500% (www.wimarcs.org). Increased numbers of hatchlings are leaving the beach, and there has been a reduction in the number and degree of impacts from poaching, vehicles, horses and predation.

The Green Sea Turtle (Chelonia mydas) is listed as threatened throughout the Caribbean, and is subject to a federal recovery plan. Unfortunately, existing regulations have not eliminated poaching, due to insufficient enforcement, and in the Virgin Islands this species is the most frequently poached of all the sea turtles. Green turtles can reach lengths of 1 m, and weigh up to 180 kg. They are circum-global, remaining in tropical and sub-tropical waters. Green sea turtles may nest
at any time of the year, although the peak nesting season is from August to October. Nesting almost always takes place at night. Females emerge and crawl up the beach (sometimes covering a considerable distance) to dig their nests, usually near vegetation, on the edge of the open beach, laying 3.5-4 clutches per year. Green turtle diet consists mainly of seagrasses and algae, although some gelatinous organisms are also ingested.

The Loggerhead Turtle (Caretta caretta) has only recently been positively identified in the USVI. In 2003 two loggerheads were identified on St. Croix. The first sighting was of a turtle that had been attacked by sharks and was found by snorkelers, who called the Division of Fish and Wildlife for positive identification. The second positive identification was of a nesting turtle on Buck Island Reef National Monument. Loggerheads are listed as threatened throughout their range. They are protected by both Federal and Territorial Laws, and are subject to a recovery plan, which is currently under revision.

Seabirds

Of the 39 seabird species that have been recorded, 15 breed in the USVI; two of these are considered threatened or endangered by the USFWS (Brown Pelican, Pelecanus occidentalis and Roseate Tern, Sterna dougallii) and two more are currently listed as territorially protected (Audubon’s Shearwater, Puffinus lherminieri; White-tailed Tropicbird, Phaethon lepturus). Boobies (family Sulidae), pelicans (Pelecanidae), and frigatebirds (Fregatidae) are present year-round, although seasonal in their nesting activities. In contrast, most petrels, shearwaters (Procellariidae), storm-petrels (Hydrobatidae), tropicbirds (Phaethontidae), jaegers, gulls, and terns (Laridae) are present only during the migratory or breeding seasons although the offshore distribution of many of these species is poorly known. Surveys of nonbreeding Procellariiformes have been inadequate in deep offshore waters, where the globally threatened Black-capped Petrel (Pterodroma hasitata) may occur. Only one of ten species of jaegers and gulls breeds locally. The remaining species rarely winter or pass through the USVI during migration. Most seabirds nest on cays and all are piscivores [fish-eaters] except for storm-petrels, which predominantly forage on zooplankton.

Most seabirds are long-lived and are characterized by deferred maturity, single annual clutches, and low reproductive rates, so time scales for population processes are very long. With the exception of some tern species, most seabirds nest at the same colony year after year, and rarely form new colonies. Due to availability of nest sites, different bird species nest on different cays.

Seabird populations on cays of the USVI remain threatened by a variety of factors despite their relatively inaccessible nest sites. Introduced predators, especially rats (Rattus spp.) have caused abandonment of colonies, and goats (Capra hircus) trample nests and vegetation. Some colonies have been abandoned due to other modes of habitat destruction or degradation. Excessive human disturbance may result in exposure and thence mortality of eggs and small chicks or colony abandonment by adults, and the illegal practice of egg collection still occurs. Other threats include declining fish stocks because of overfishing, pollution, entanglement in fishing line, predation by Laughing Gull and Peregrine Falcons, and storms, especially during the breeding season. The Society for the Conservation and Study of Caribbean Birds (formerly the Society of Caribbean Ornithology), which published the “Status and Conservation of West Indian Seabirds”, states that many of the region’s seabirds are in serious decline. The major reasons cited for the declines are habitat destruction and disturbance, human consumption of eggs and birds, the introduction of non-native animals, and pollution.

Boobies

The ground-nesting Brown Booby (Sula leucogaster) is the most common and widely distributed Sulid in the Virgin Islands. Brown Boobies nest on four offshore cays, with an estimated breeding population of 1000 pairs. Because boobies are longlived, population size and other demographic parameters, should be monitored over the long-term.

Brown Pelican

The Caribbean race of the Brown Pelican (Pelecanus o. occidentalis), listed by the USFWS as an endangered species, ranges throughout the West Indies. In St. Croix, breeding colonies occur at Buck Island and Green Cay off northern St. Croix. Pelicans normally nest in trees and shrubs but after hurricanes may nest on fallen vegetation or on the ground. The current minimum breeding population of Brown Pelicans in the USVI has maintained itself at ca. 300-350 pairs.

Non-breeding pelicans are widely distributed. In St. Croix, many birds are concentrated along the southwest coast where more food is apparently available. Large numbers of post-breeding birds apparently disperse from the USVI to Puerto Rico. Small numbers occasionally roost at freshwater wetlands. The factors affecting the non-breeding abundance and distribution of Brown Pelicans in the USVI remain poorly known.

Because of their large size, pelican eggs and chicks are more resistant to predation by the Roof Rat (Rattus rattus). Nevertheless, removal of rats from cays where pelicans nest will undoubtedly benefit pelicans. The causal factors of population decline are apparently unrelated to roosting and nesting habitat loss, or chemical contamination, and have yet to be identified.

Magnificent Frigatebird

The Magnificent Frigatebird (Fregata magnificens) regularly forages and roosts in the USVI, but the only current nesting colony in the region is on Tobago Island, BVI. Frigatebirds are a species of concern; their breeding populations are proposed as territorially endangered, and they are considered one of the most threatened seabirds in the West Indies.

Elsewhere in the Caribbean, loss of nesting habitat due to extensive development has caused the extirpation of historic frigatebird colonies. In the Virgin Islands, entanglement in fishing line is probably the leading cause of death in frigatebirds. Fishermen, especially those fishing with live bait that floats on the surface, accidentally hook birds. If the line is cut, the frigatebirds (as well as boobies and pelicans) trail the line back to the nesting colony where it accumulates in the habitat, snaring adult and young. Because of their extreme life history characteristics, such as delayed sexual maturity (up to 8 years) and less than annual breeding cycle, the loss of so many birds may eventually overcome their reproductive potential to maintain a viable population in the USVI.

Tropicbirds

Two species of tropicbirds breed in the USVI. Tropicbirds nest in crevices or under thick vegetation where one egg is laid on bare ground. Most nests are inaccessible and dangerous to survey owing to their location on steep cliff faces. Both species have strong nest site and mate fidelity. The habit of tropicbirds to make repeated aerial approaches to the nest site before landing aids the detection of nesting birds in inaccessible areas, but also attracts Peregrine Falcons, which routinely patrol colonies and kill both adults and chicks in their nest sites. Thus, predation and to a lesser extent the availability of suitable nest sites, appear to be the limiting factors for tropicbirds breeding in the USVI.

One or two pairs of the territorially threatened White-tailed Tropicbird (Phaethon lepturus) nests at cliff sites on the southside of St. Croix. Their breeding season occurs from April through August. Competition for nest sites with the more numerous Red-billed Tropicbird, which breeds from October through May, doesn’t occur in the USVI. The White-tailed Tropicbirds prefer to nest on cliff faces on the larger islands, while the Red-billed Tropicbirds show a preference for smaller cays.

The Red-billed Tropicbird (Phaethon aethereus) breeds on at least 14 cays off St. Thomas and St. John, with a current population estimate of 225-300 pairs. Results from a 3-year study of banded birds at 6 offshore cays showed a sharp decline in the number of nests at three of the nesting colonies. Intra-specific fighting between billed Tropicbirds over nest sites has been observed.

Gulls and Terns

The widely distributed Laughing Gull (Larus atricilla) is the only gull that breeds in the USVI. The first migratory breeder to appear in the USVI during late March, nests are found from May through August on many of the cays; the estimated breeding population in the USVI is 2000-3000 pairs. Laughing Gulls routinely feed on food discarded by humans and have thus benefited from human activities; because they often prey on the eggs and young of terns, including the federally threatened Roseate Tern (Sterna dougallii), their burgeoning numbers are of concern, although a federal depredation permit is required to control their populations.

Seven of 15 species of migratory terns breed locally; their colony sites and populations generally fluctuate from year to year, sometimes dramatically, especially the federally threatened Roseate Tern. Although small numbers of Royal (S. maxima) and Sandwich Terns (Sterna sandvicensis) from North American populations overwinter in the USVI, the remaining species depart from the USVI after the breeding season. With the exception of the Roseate Tern, very little is known about the non-breeding habits of these species. The pelagic Sooty Tern (S. fuscata) is the first tern to arrive in mid- to late-April. The Sooty Tern is the most abundant seabird breeding in the USVI, as well as in the wider Caribbean region.

The Bridled Tern (S. anaethetus) can be confused with the similar-looking Sooty Tern, however breeding regimes are much different. Bridled Terns nest in small, loose aggregations on many offshore cays with suitable habitat where they conceal their nests in crevices or under low vegetation, making them difficult to survey. The total USVI population is estimated at 400-1000 pairs. Regional populations do not appear in trouble at this time, however, very little is known about this species’ nesting ecology in the Caribbean.

The Roseate Tern is an intermediate-sized, ground-nesting, colonial seabird whose populations are listed by the USFWS as endangered in the northeastern U.S. and threatened in the Caribbean. Although the Caribbean population breeds from Florida through the West Indies to islands off Central America and northern South America, the largest colonies occur on the Puerto Rican Bank, in Puerto Rico and the Virgin Islands, where Roseate Terns may choose a suitable nesting location in one year and ignore it in other years, or they may choose the same islands in successive years. None of the 17 breeding sites recorded in the USVI since 1987 has been used in every year. Such unpredictable and sporadic use of nesting colonies hinders attempts to manage them.

Unlike the Roseate Terns of the northeastern United States, which tend to nest under vegetation or other shelter, Caribbean populations nest in more open situations near vegetation, on narrow rock ledges, on steep slopes, or among coral rubble. Hence, they are easier to survey and monitor once on site, though may be difficult to reach. Eggs (usually 1- or 2-egg nests are found) are usually laid directly on the ground, rock, or vegetation with little or no nest material added. Eggs and young chicks are vulnerable to predators at the more exposed nest sites when parents are absent. Colonies are highly susceptible to disturbance in the early stages of egg-laying and may relocate during the breeding season, often joining an established group of nesters. Colonies formed late in the breeding season are usually small and rarely fledge young.

Post-breeding movements of Caribbean Roseate Terns are poorly known. Parents move with their chicks to staging areas near their natal colonies and continue to feed the chicks for up to six weeks. Most birds have departed on their southward migration by September. Some Caribbean and northeastern birds mingle throughout the winter from Guyana to Brazil where most banded recoveries have occurred. Recoveries in Brazil of Roseate Terns from northeastern and Caribbean populations demonstrate that both mix to some degree during the non-breeding season and subsequently, banding data have also revealed that some birds from Puerto Rico and the USVI spend the non-breeding season near Manque Seco, Brazil. Because all recovered birds were banded as adults, young and adult birds may move to different areas in the non-breeding season, like Sooty Terns.

Roseate Tern colonies in the USVI are particularly vulnerable to human disturbance because they are often precariously situated on readily accessible islands located near heavily used tourist areas. Humans innocently or intentionally harass the colonies and occasionally poach bird eggs for consumption, which often results in colony abandonment. Other major threats include predation on eggs or chicks by: (1) Laughing Gulls, which prey on eggs and chicks, (2) rats, which prey on eggs and possibly chicks; and (3) fire ants (Solenopsis spp.), which occasionally feed on pipping eggs and chicks. Outside of the region, wintering terns along the northeastern coast of South America are often killed for human consumption, a practice which continues.

The Brown Noddy (Anous stolidus) is a fairly common breeding seabird. In the USVI, it nests in three habitat types: cliff ledges and small rock outcroppings, trees (only at Frenchcap Cay, St. Thomas) and on the ground. Noddies lay 1 egg. An estimated 600-800 pairs of noddies nest at numerous cays with suitable habitat. Brown Noddies exhibit a high degree of mate and nest site fidelity.

The Sandwich and Royal Terns usually nest together in densely-packed colonies on several cays in the USVI. The Sandwich Terns (ca. 50-700 pairs) far outnumber the Royal Terns (65-160 pairs). Both terns lay 1 egg and may nest on different islands in successive years. Once chicks are several days old, they crèche, or group together and are highly vulnerable to disturbance. The “Cayenne” Tern (S. s. eurygnatha), currently considered a South American race of the Sandwich Tern, nests in small numbers among colonies of the Sandwich Tern, with which it hybridizes; the systematic relationship between the two taxa is poorly understood.

In contrast to other terns, most Least Terns (S. antillarum antillarum) nest at St. Croix, where the breeding population is currently 300-325 pairs. On St. Croix, the Least Terns have been recorded nesting at 26 sites in various habitat types, including beaches, salt flats, a dredge spoil pile, gravel parking lot and the containment areas around storage tanks and roads at the HOVENSA oil refinery. Available data suggest that the population has suffered a serious decline in St. Croix, however studies are currently underway to assess the status of the species. Predation by dogs, cats, and mongoose and human disturbance are responsible for most nest failures. The Caribbean race of Least Terns is not federally listed, however, this species is territorially listed as endangered.

Waterfowl, Marsh Birds & Shore Birds

Twenty-tree species of waterfowl (family Anatidae) have been recorded within the USVI, but only three have been documented to breed here. Non-breeding waterfowl comprise two groups: Nearctic migrants (15 species), which breed in North America and regularly or rarely winter during the non-breeding season in the USVI, and rare visitors that breed elsewhere in the Caribbean or South and Middle America (Intratropical migrants; four species).

Marshbirds include a heterogeneous assemblage of families: grebes (Podicipedidae), waders (Ardeidae, Threskiornithidae, and Poenicopteridae), and rails, gallinules, and coots (Rallidae). Two grebes occur in the USVI, and fifteen species of waders have been recorded, including four vagrants. Six species of rallids have been documented within the USVI, excluding the flightless De Booy’s Rail (Nesotrochis debooyi) that became extinct before the arrival of Europeans. Four of these rallids are breeding residents.

Shorebirds (families Charadriidae, Haematopidae, Recurvirostridae, and Scolopacidae) are long-billed, long-necked, and long-legged birds that typically feed on invertebrates along or near the shoreline or in short grasslands. Thirty-seven species, the largest single taxonomic group in the USVI, have been recorded from these islands and 24 of these species are of potential and practical management concern. Five shorebirds currently breed within the USVI.

The major threats to waterfowl, shorebirds, and other water birds within the USVI are the loss or degradation of wetland habitats (especially coastal salt ponds and lagoons), beach development, and human recreational use of beaches. Populations suffer an additional threat from predation by Small Indian Mongoose (Herpestes javanicus) and other exotic mammalian predators on eggs and possibly ducklings. Hurricanes and tropical storms potentially destroy nesting and roosting trees of some species, and alter wetland habitats, but their effects on waterbird populations are poorly known. Although saline wetland habitats have decreased due to extensive development along the coast, man-made freshwater wetland habitat has increased, especially on golf courses and farms where ponds may provide a seasonal or year-round supply of freshwater. Waterfowl populations were once adversely affected by hunting, but waterfowl hunting is no longer permitted in the USVI and poachers probably bag no more than a few individuals per year.

Mangroves are the only wildlife habitat that has some legal protection in the USVI. Suitable wetland habitats need to be preserved, especially for shorebirds that require refueling during migration. Fortunately, many of the non-breeding species of shorebirds in particular can be effectively managed as a group because most co-occur in similar habitats at most of the same sites.

Waterfowl

The most common breeding species is the White-cheeked Pintail (Anas bahamensis), which breeds on cays, especially those with salt ponds, and at or near a variety of wetlands on major islands. Its numbers appear to be increasing, and a recent population shift toward resorts has occurred in the northern USVI where they are fed by tourists, thus posing potential health risks in swimming pools and restaurants.

The globally endangered West Indian Whistling-Duck (Dendrocygna arborea) formerly bred in St. Croix, but unregulated hunting and poaching have extirpated it from the Virgin Islands, although they still breed elsewhere in the Greater Antilles, the Bahamas, and some of the Lesser Antillean islands. Two individuals were recently observed on St. Croix in October 2002, perhaps representing vagrants from Puerto Rico. These were the first documented in the USVI since 1941. Regardless, St. Croix has sufficient wetlands to support reintroduction of this species.

The territorially endangered Ruddy Duck (Oxyura jamaicensis), now proposed as a species of special concern, had been reported nesting only once on St. Croix, probably about a century ago, until 2005 when several pairs nested at Southgate Pond. Non-breeding Ruddy Ducks, though rare, regularly visit the USVI year-round, the nominate race from adjacent islands in the eastern Greater Antilles and northern Lesser Antilles, as well as long-distance migrants from North America.

The dominant non-breeding waterfowl is the Blue-winged Teal (A. discors), which is the only non-indigenous duck that is widespread and fairly common in the USVI where it generally prefers freshwater sites and some salt ponds. It is most numerous during vernal and autumnal migrations.

The other two regularly occuring current migrants from North America, the Ring-necked Duck (Aythya collaris) and Lesser Scaup (A. affinis), are nonetheless too scarce to justify separate management measures in the USVI. However, these and other scarce waterfowl are likely to benefit from many conservation actions for the three indigenous breeding species and the Blue-winged Teal.

Ruddy Duck female, Oxyura jamaicensis [photo Carol Cramer-Burke, courtesy of SEA].

Ruddy Duck male, Oxyura jamaicensis [photo Carol Cramer-Burke, courtesy of SEA].

Marshbirds

Least (Tachybaptus dominicus) and Pied-billed (Podilymbus podiceps) grebes breed in freshwater ponds and a few salt ponds throughout the major islands of the USVI. Their status had been poorly documented because previous studies of wildlife populations using wetlands ignored man-made freshwater ponds. However, recent intensive surveys revealed both species to be more numerous than previously believed, and possibly increasing, even though the Least Grebe is rare and still territorially endangered. The Least Grebe may be more numerous on St. Thomas and St. John whereas the Pied-billed Grebe is most common on St. Croix.

The status of five species listed as territorially endangered, i.e., Least Bittern (Ixobrychus exilis), Great Blue Heron (Ardea herodias), Great Egret (A. alba), Snowy Egret (Egretta thula), and Black-crowned Night-Heron (Nycticorax nycticorax) has been reassessed. Only the Least Bittern is proposed to be retained, whereas the Great Egret is proposed for delisting and the other three species for downlisting because the conservation of these geographically widespread species is a lower priority. Two other waders are now proposed for listing, the uncommon Tricolored Heron (E. tricolor), which is at the periphery of its range, and the Cattle Egret (Bubulcus ibis).

Although most waders breed in wetlands, the breeding status of several suspected to nest in the USVI remains unknown or poorly documented, especially the Least Bittern and Great Blue Heron. The Least Bittern has probably been extirpated from its mangrove habitat.

The Cattle Egret is a trans-Atlantic colonist from Africa first recorded in the USVI in the 1950s, when it began to breed; it is now the most abundant wader and a predator of the federally endangered St. Croix Ground Lizard (Ameiva polops) on Protestant Cay. Consequently, the Cattle Egret is proposed for listing as a controlled species because it also usurps nest-sites from more desirable herons and egrets, constitutes one of the two major bird/aircraft strike hazards at airports, and can be a nuisance at urban roosting or breeding sites on St. Croix.

Other waders not heretofore mentioned that are widespread throughout the USVI include the Little Blue Heron (E. caerulea), Green Heron (Butorides virescens), and Yellow-crowned Night Heron (Nyctanassa violacea). The Little Blue Heron is the wader most frequently seen along coastal shorelines feeding in the surf, the Green Heron is the only heron that regularly breeds at freshwater sites as well as saline sites, and solitary pairs of the Yellow-crowned Night Heron usually breed in secluded tidally-influenced mangroves.

Several other waders are Nearctic migrants that rarely winter in the USVI, or are rare visitors that breed elsewhere in the Caribbean. The most charismatic of these species is the Greater Flamingo (Phoenicopterus ruber), which has been reintroduced to Anegada and Guana Island, BVI. Although breeding has never been reported from the USVI, where reintroduction is not recommended, reports of vagrants may increase. Greater Flamingos were probably once more numerous in the USVI, at least on St. Croix, as a non-breeding visitor.

Four species of rallids are breeding residents: Clapper Rail (Rallus longirostris), Common Moorhen (Gallinula chloropus), American Coot (Fulica americana), and Caribbean Coot (F. caribaea). The Common Moorhen is a common resident of freshwater and some saline wetlands throughout the USVI. The territorially endangered Caribbean Coot breeds intermittently on St. Croix, where it may hybridize with the American Coot, especially at Southgate Pond where their breeding ecology has recently been studied. The Sora (Porzana carolina) is a Nearctic migrant that winters in the region and the Purple Gallinule (Porphyrio martinica) is a very rare visitor that breeds elsewhere in the Caribbean.

The Double-crested Cormorant (Phalacrocorax auritus) is a rare visitor in the USVI from North America. The USVI is at the periphery of its nonbreeding range.

Shorebirds

Shorebirds that breed within the USVI are Wilson’s Plover (Charadrius wilsonia), Black-necked Stilt (Himantopus mexicanus), Killdeer (C. vociferus), American Oystercatcher (Haematopus palliatus), and Willet (Catoptrophorus semipalmatus). The Wilson’s Plover and Black-necked Stilt frequently co-occur in mangrove wetlands; the former species nests along beaches, berms, dry bottoms of salt ponds, and salt flats, whereas the Black-necked Stilt nests in salt ponds and salt flats. Both species, especially the stilt, respond rapidly to water level fluctuations in mangrove wetlands. An estimated 40 pairs of Wilson’s Plover nest at about 17 sites on St. Croix, which is about 5% of the mainland United States breeding population. Thus, the wetlands of St. Croix are of regional importance for the conservation of Wilson’s Plover, which is proposed to be territorially listed as a species of special concern. Wilson’s Plovers also nest in the northern USVI where they probably number no more than 15-20 pairs.

Over 60 pairs of Black-necked Stilt nest at about 14 sites on St. Croix, where breeding individuals are apparently outnumbered by non-breeding adults. Black-necked Stilts are fairly numerous in the northern USVI, but population estimates there are less certain.

The Killdeer usually nests in dry, open habitats and has increased in the USVI. The American Oystercatcher is widespread but uncommon and apparently declining throughout the islands, where it regularly nests on Green Cay and Ruth Island off St. Croix. A few pairs of Willet also breed at Ruth Island, the only site in the USVI; elsewhere they are a rare migrant. The Snowy Plover (C. alexandrinus) may have formerly nested at St. Croix but this is uncertain. A small population breeds in Anegada, BVI, although it very rarely visits the USVI where it has been recorded in St. John and St. Croix.

Land Birds

More than half of the landbirds breeding in North America migrate southward to winter in the Caribbean, Central America, or South America. Collectively termed Nearctic migrants, these species exploit seasonal feeding opportunities throughout the year. However, they are vulnerable to adverse weather, predation, and navigational hazards during migration, and are sensitive to habitat reduction, fragmentation, and degradation in their breeding and wintering ranges, and also along their intervening migratory pathways, including the Eastern Caribbean.

In the USVI, at least 59 species of Nearctic landbird migrants have been recorded, including five raptors (families Accipitridae and Falconidae), one cuckoo (Cuculidae), two nightjars (Caprimulgidae), one swift (Apodidae), one kingfisher (Alcedinidae), one woodpecker (Picidae), one flycatcher (Tyrannidae), three vireos (Vireonidae), six swallows (Hirundinidae), two thrushes (Turdidae), 30 warblers (Parulidae), one tanager (Thraupidae), three grosbeaks and buntings (Cardinalidae), and two blackbirds (Icteridae). Of these 59 species, almost half are stragglers (vagrants), including 13 parulids. Of the remaining 30 species, 14 are proposed to be territorially listed as species of special concern or peripheral, including nine parulids such as the Prothonotary (Protonotaria citrea) and Hooded (Wilsonia citrina) warblers.

Many Nearctic migratory landbirds, especially warblers, winter regularly within the USVI where the best habitat is mature intact forest on St. John. The most common wintering species in the USVI include Belted Kingfisher (Ceryle alcyon), Barn Swallow (Hirundo rustica), Northern Parula (Parula americana), Prairie (Dendroica discolor) and Black-and-white (Mniotilta varia) warblers, American Redstart (Setophaga ruticilla), and Northern Waterthrush (Seiurus noveboracensis). Some other species such as the Blackpoll (D. striata) and Connecticut (Oporornis agilis) warblers are most numerous in the USVI and elsewhere in the eastern Caribbean as autumnal migrants or vernal transients such as the rare Scarlet Tanager (Piranga olivacea).

The 17 resident landbirds include one hawk (family Accipitridae), one falcon (Falconidae), two cuckoos (Cuculidae), one owl (Strigidae), three hummingbirds (Trochilidae), three flycatchers (Tyrannidae), two mimids (Mimidae), one warbler (Parulidae), one bananaquit (Genus Incertae Sedis), and two seed-eating finches (Emberizidae).

Pigeons and doves (“columbids”; family Columbidae) are common to tropical and subtropical islands. Often species recorded in the USVI, seven have established populations. Two species have been listed as territorially endangered but appear to have partially recovered and are now proposed to be listed as threatened. Avian distributions in the USVI have been influenced by human-caused extirpations and extinctions. This includes documentation of the extinction of at least four species of resident landbirds, based on excavation of fossil and pre-historic birds at American Indian kitchen middens. The most famous of these are the De Booy’s Rail (Nesotrochis debooyi), a land rail that was apparently numerous in upland habitats throughout the USVI, and the St. Croix Macaw (Ara autocthones). Other avian species may have become extinct during the post-Columbian era when native forest was extensively cleared for plantation agriculture during the 17th and 18th centuries, such as the Puerto Rican Lizard-Cuckoo (Saurothera vieilloti), Puerto Rican Woodpecker (Melanerpes portoricensis), and Whitenecked Crow (Corvus leucognaphalus).

In addition to the proposed addition of the extirpated White-necked Crow to the territorial endangered species list, three resident landbirds are regarded as territorially endangered: the Puerto Rican Screech-Owl (Megascops nudipes), Antillean Mango (Anthracothorax dominicus aurulentus), and Puerto Rican Flycatcher (Myiarchus antillarum). Two resident landbirds are proposed to be downlisted to threatened status, the White-crowned Pigeon (Patagioenas leucocephala) and Bridled Quail-Dove (Geotrygon mystacea), as well as one intratropical migrant, the Antillean Nighthawk (Chordeiles gundlachii). Other residents and migrants are proposed as species of special concern.

Continental population declines have been documented in some of the Nearctic migrant landbirds and this is locally reflected in some of the proposed listings. The declining populations of some landbirds underscore the importance of preserving or enhancing their remaining habitat, especially mature mesic, xeric, or mangrove forest. The primary causal factor of population declines in migratory landbirds is the loss, fragmentation, and degradation of habitat for development in both the breeding and wintering ranges. The loss of mature mangrove forest on St. Croix, from the irreplaceable man-made destruction of Krause Lagoon in the early 1960s and its natural elimination at Sugar Bay (part of the Salt River Bay system) by Hurricane Hugo in 1989, has seriously diminished species composition and abundance of Nearctic migrants on the big island. The loss, fragmentation, and degradation of habitat for development remains the primary threat to landbirds. Other threats include predation, especially of eggs and young, by exotic predators including the Domestic Cat (Felis domesticus) and Small Indian Mongoose (Herpestes javanicus), collisions with vehicles and man-made structures, wanton destruction of nests by humans, and poisoning by insecticides, herbicides, and other chemicals. Tall, lighted structures cause considerable mortality during migration, especially on cloudy nights when birds often fly into them or their supporting structures. The potential role of migratory landbirds as carriers of West Nile virus in the Caribbean remains poorly known, although this disease has now been verified from birds nearby in eastern Puerto Rico.

Hawks

There are seven hawks (families Accipitridae and Falconidae) recorded in the USVI, two residents, the American Kestrel (Falco sparverius) and the Red-tailed Hawk (Buteo jamaicensis). The other species, Osprey (Pandion haliaetus), Northern Harrier (Circus cyaneus), Sharp-shinned Hawk (Accipiter striatus), Merlin (Falco columbarius), and Peregrine Falcon (Falco peregrinus) are Nearctic migrants.

The Peregrine Falcon was formerly listed as federally endangered, although its populations have been recovering from the adverse effects of DDT, a banned pesticide, on its reproductive biology. Consequently, its proposed downlisted territorial status is special concern even though predation by Peregrines at important seabird colonies in the northern USVI during winter may be an important cause of mortality.

The American Kestrel is a permanent resident of North and South America from Alaska and Canada south to Tierra del Fuego, and across the West Indies. It is generally absent from heavily forested areas. It nests in tree cavities, crevices of buildings, and readily uses artificial nest boxes. It prefers open ground where it can easily hunt from high perches. American Kestrel populations have declined in the Virgin Islands due to the loss of nesting habitat from development and hurricanes. During the breeding season, from February when the eggs are laid through to fledging, the kestrels are very aggressive towards intruders and perceived threats. DFW receives many complaints from the public during this time regarding attacks by these birds when they have nested in cavities in houses or nearby trees. The installation of artificial nest boxes away from the house and sealing the cavity reduce the likelihood of attacks. DFW has a program for installing nest boxes for kestrels in cases of nuisance animals.

Pigeons and Doves

Pigeons and doves (“columbids”; family Columbidae) are an avifaunal feature of tropical and subtropical islands. Often species recorded in the USVI, seven have established populations: Rock Pigeon (Columba livia), Scaly-naped Pigeon (Patagioenas squamosa), White-crowned Pigeon (P. leucocephala), White-winged Dove (Zenaida asiatica), Zenaida Dove (Z. aurita), Common Ground-Dove (Columbina passerina), and Bridled Quail-Dove (Geotrygon mystacea). In addition, the Ruddy Ground-Dove (G. montana) purportedly occurs as a vagrant on St. Croix, the Ringed Turtle-Dove (Streptopelia turtur) has been reported as an escapee on St. Croix, and the Spotted Dove (S. chinensis) as a failed introduction in St. Croix, but these reports are unconfirmed. Four columbids are exotics from the Old World: the Rock Pigeon (represented by a genetically altered, domesticated strain widely introduced in the Americas) and the three Streptopelia doves. The Eurasian Collared-Dove may colonize the USVI, as it has elsewhere in the region following its introduction in the Bahamas in 1974. All of these columbids occupy habitats that range from urban areas to closed mesic forest where they feed on a diet of seeds and fruit.

Two species of columbids have been listed as territorially endangered, the Whitecrowned Pigeon and Bridled Quail-Dove, but appear to have partially recovered and are now proposed to be listed as threatened species. The former species nests and roosts in mangroves and littoral forest on larger islands and cays. It forages mostly in littoral forest and less often in upland forests. Many individuals leave the USVI during winter. Although once hunted, the White-crowned Pigeon has been protected in the USVI for over 40 years and should remain protected because of its pronounced long-term population decline and general low numbers in the Caribbean where large numbers are still shot. Limited poaching still occurs on St. Croix, especially of squabs from nests at one of the two main breeding colonies at Ruth Island. The White-crowned Pigeon is locally uncommon to common in St. Croix.

The Bridled Quail-Dove resides in the forest interior of all three major islands, occurring at all elevations. It is fairly common on St. John, uncommon on northwestern St. Croix, and rare and local in forest guts of western St. Thomas. Its inter-island movements in response to hurricane effects remain undocumented, unlike many intra- and inter-island movements of other columbids (such as Scaly-naped Pigeons), yet quail-doves have reestablished a small population in northwestern St. Croix where they were thought to have become extirpated following Hurricane Hugo in 1989. This conundrum emphasizes how little we know about the process of recovery of quaildove populations on St. Croix.

Of the three columbids in the USVI classified by the USFWS as migratory game species, only the Zenaida Dove is currently hunted (during September); because it is abundant, its hunting season could be extended. The exotic Rock Pigeon can be legally killed year-round since it is an unprotected species. The Scaly-naped Pigeon was hunted until 1991, when hunting was suspended because populations were thought to be low and declining from poaching, the loss of forest habitat caused by Hurricane Hugo, and incidental take of the similar but rarer White-crowned Pigeon . However, Scaly-naped Pigeon populations recovered quickly from the short-term effects of hurricanes Hugo (1989) and George (1998) at Vieques and elsewhere in Puerto Rico, where populations could be sustainably harvested even one year after a hurricane. Furthermore, poaching of all columbids is now a local, negligible problem in the USVI, except for nesting White-crowned Pigeons on Ruth Island. The Scaly-naped Pigeon is now common throughout the USVI. A partial population recovery of White-crowned Pigeons may facilitate resumption of the Scaly-naped Pigeon hunt, but because few hunters distinguish between the two species (both are locally named blue pigeons), incidental take would need to be monitored. Several other columbids were also formerly hunted in the USVI but are now protected. This includes the fist-sized Common Ground-Dove. Despite a sharp decrease over the last 50 years, it is still widely distributed and locally abundant in open scrubby habitats throughout the USVI, especially on some cays and in xeric coastal areas.

The USFWS funded the introduction of two exotic columbids (and other gamebirds), the Spotted Dove and White-winged Dove in the mid-1960s, which ultimately failed. Ironically, the White-winged Dove began a natural, explosive range expansion to the USVI in the late 1990s, presumably from Puerto Rico where populations have increased. Most birds are absent in the USVI during winter (November to February) but breeding populations have become established. The White-winged Dove is unlikely to become a game bird in the USVI because it occupies restricted habitat, usually in or near inhabited areas (e.g., golf courses, hotel resorts, and large school yards), and is local and uncommon, though increasing.

Aside from the former threats of overhunting and illegal poaching, the major current threat to columbids in the USVI is destruction of habitat by development and hurricanes. The White-crowned Pigeon is especially sensitive to habitat destruction because it is dependent upon coastal habitats where development is most intense. The potential colonization of the USVI by the Eurasian Collared-Dove may threaten native species through competition for food and nest sites.

Cuckoos

The Yellow-billed Cuckoo (Coccyzus americanus; family Cuculidae) is a Nearctic migrant, while the other two species, the Mangrove Cuckoo (Coccyzus minor) and the Smooth-billed Ani (Crotophaga ani) are residents of the USVI. The Mangrove Cuckoo inhabits mangrove swamps, and is also widespread and numerous in scrubby secondary forests. The Smooth-billed Ani occurs in small flocks in semi-open habitats, including mangrove forests, colonially nesting in the same nest incubated by the entire colony. The Yellow-billed Cuckoo is an uncommon autumnal migrant, occurring in arid scrublands and mangrove swamps and woodlands at lower elevations. It is proposed as a territorial peripheral species because it formerly nested on St. Croix in riparian habitat during the 19th century. The other two species are widely distributed, numerous, and of lesser management concern.

Owls

The Puerto Rican Screech-Owl (Megascops nudipes; family Strigidae) is a relict Greater Antillean species. It formerly resided in the forested interior on the three large islands but its presence has not been confirmed since a specimen was collected in St. Croix in 1936. Subsequent reports are probably erroneous and intensive searches on all three islands have failed to find it. It is territorially listed as endangered.

Nightjars

The Antillean Nighthawk (Chordeiles gundlachii; family Caprimulgidae) is an intratropical migrant that is a rare to uncommon, local resident of open areas on the three main islands in the USVI, near the eastern periphery of its breeding range. St. Croix is the only island where they have been recently confirmed to nest, with a population of probably around ten pairs. The Antillean Nighthawk is proposed to be downlisted from territorially endangered to threatened status. The Common Nighthawk (Chordeiles minor) and Chuck-will’s Widow (Caprimulgus carolinensis) are Nearctic migrants, with the latter species being a scarce winter resident.

Swifts

The Black Swift (Cypseloides niger; family Apodidae) is an intratropical migrant that breeds in larger islands of the Greater and Lesser Antilles, and is a very rare transient in the USVI where it has been reported three times on St. Croix. The Chimney Swift (Chaetura pelagica) is a rare Nearctic migrant.

Hummingbirds

Three resident hummingbirds (family Trochilidae) are resident in the USVI. The nectivorous Green-throated Carib (Eulampis holosericeus) and the Antillean Crested Hummingbird (Orthorhyncus cristatus) are widely distributed and fairly common to forests and woodlands. The Purple-throated Carib (Eulampis jugularis) is vagrant in the USVI.

Flycatchers

The two resident flycatchers (family Tyrannidae) on St. Croix are the Caribbean Elaenia (Elaenia martinica) and Gray Kingbird (Tyrannus dominicensis). The Elaenia and Kingbird are widely distributed on the three major islands and many cays, where they are numerous in scrubby open areas with scattered trees and open woodlands.

Vireos

The Black-whiskered Vireo (Vireo altiloquus; Vireonidae) is an intratropical migrant, occurring throughout the USVI in all main forest habitat types, including isolated xeric guts on the windward sides of the main islands if at least some taller brushy areas are available. This vireo appears to be numerous in mature mangrove forest, when available, and the few that remain during winter are concentrated in this habitat. One subspecies occurs in in St. Croix (and the Lesser Antilles): V. a. barbadensis . Three other vireos recorded in the USVI are the White-eyed Vireo (Vireo griseus), a vagrant, and the Yellow-throated Vireo (V. flavifrons) and Red-eyed Vireo (V. olivaceus), both being Nearctic migrants.

Swallows

The Caribbean Martin (Progne subis; family Hirundinidae) is an uncommon, local intratropical migrant occurring throughout the USVI, where it breeds in cliff crevices along promontories, on a few cays, and in cavities in man-made structures (e.g., at the tip of the Frederiksted Pier on St. Croix). The other swallows present in the USVI, the Barn Swallow (Hirundo rustica), Tree Swallow (Tachycineta bicolor), Northern Rough-winged Swallow (Stelgidopteryx serripennis), Bank Swallow (Riparia riparia), and Cliff Swallow (Petrochelidon pyrrhonota) are Nearctic migrants. The Cave Swallow (Petrochelidon fulva) is an intratropical vagrant to the USVI.

Warblers

Within the USVI 30 species of warblers (family Parulidae) are Nearctic migrants. Many of these warblers winter regularly within the USVI where the best habitat is mature continuous forest, formerly, mature mangrove forest at Sugar Bay on St. Croix. The most common wintering species include the Northern Parula (Parula americana), Prairie (Dendroica discolor) and Black-and-white (Mniotilta varia) warblers, American Redstart (Setophaga ruticilla), and Northern Waterthrush (Seiurus noveboracensis). Some other species such as the Blackpoll (D. striata) and Connecticut (Oporornis agilis) warblers occur primarily in the USVI and elsewhere in the eastern Caribbean as autumnal migrants.

The Yellow Warbler (Dendroica petechia) is a resident, inhabiting mangroves, lowland open woodland and scrub. Nine parulids are proposed to be territorially listed as species of special concern or peripheral, including the Prothonotary (Protonotaria citrea) and Hooded (Wilsonia citrina) warblers.

Other Landbirds

The most intriguing change in status of any resident landbird is the range expansion of the Lesser Antillean Bullfinch (Loxigilla noctis; family Emberizidae) from the Lesser Antilles, although whether this range expansion is natural or human-assisted is in dispute. This bullfinch remains rare in St. Croix, where first reported in 1979.

Other resident landbirds include the fairly common to abundant Bananaquit (Genus Incertae Sedis; family Coerebidae), Northern Mockingbird (Mimus polyglottos), Pearly-eyed Thrasher (Margarops fuscatus; family Mimidae) and the Black-faced Grassquit (Tiaris bicolor; family Emberizidae). Other Nearctic migrants recorded in the USVI include the fairly common winter resident Belted Kingfisher (Ceryle alcyon; family Alcedinidae), and scarce transients including the Veery (Catharus fuscescens) and Gray-cheeked Thrush (C. minimus; family Turdidae), and the Yellow-bellied sapsucker (Sphyrapicus varius; family Picidae), which is listed as a local species of special concern. The rare Scarlet Tanager (Piranga olivacea; family Thraupidae) is a vernal transient.

Additionally, three members of the family Cardinalidae are recorded in the USVI: Rose-beaked Grosbeak (Pheucticus ludovicianus), Blue Grosbeak (Passerina caerulea), and Indigo Bunting (Passerina cyanea).

Mammals

Because of their long history of isolation, the USVI are inhabited by few native species of terrestrial mammals. At least two species are known to be extinct, based on excavation of fossil remains unearthed in American Indian kitchen middens: the rodent Isolobon portoricensis and the insectivore Nesophontes edithae. Among terrestrial mammals, bats are the most successful colonists of small, isolated islands because of their strong dispersal abilities, small body sizes, and low trophic level. Six species of bats are recorded within the USVI. Eleven species of mammals have established feral or free-ranging populations, including: Domestic Cat (Felis domesticus), Domestic Dog (Canis familiaris), Small Indian Mongoose (Herpestes javanicus), Horse (Equus caballus), Pig (Sus scrofa), White-tailed Deer (Odocoileus virginianus), Goat (Capra hircus), Roof Rat (Rattus rattus), Norway Rat (Rattus norvegicus), and House Mouse (Mus musculus). Non-native species impacts are discussed further in the Exotic Species chapter. Additionally, several species of marine mammals occur in offshore waters.

Bats

The extant native terrestrial mammal fauna in St. Croix is limited to five species of bats. Although none is endemic to the USVI, the rare frugivorous Red Fig-eating Bat (Stenoder