Rota Avian Behavioral Ecology Program

University of Washington, Psychology Department
Box 351525, Seattle, WA 98195

RABEP Field Station
P.O. Box 1298, Rota, MP 96951
Northern Mariana Islands


The brown tree snake, Boiga irregularis, is native to eastern Indonesia, the Solomon Islands, New Guinea, and the northern and eastern coasts of Australia.  This species was identified on the island of Guam in the 1950's and was likely introduced accidentally either in imported cargo or in the wheel wells of commercial and military aircraft. 

The brown tree snake is a generalist predator which is known to have decimated Guam's avifauna and impacted native mammal and reptile populations.  This species has been reported on Saipan, and there is some indication that it could be spreading there.  To date, there has only been one report of a snake on Rota, though there is concern that the snake could spread to the island.

Nearly 75% of t
he native, resident bird species found in the CNMI are similar to those found on Guam before the snake's introduction. Therefore, the Mariana islands offer a prey base capable of supporting brown tree snakes.  Six of these species are federally listed as endangered or threatened, and it is these species that are of special concern to researchers and wildlife managers.

Visit the USGS website for more information.

Mariana Crow
Corvus kubaryi

Range: Rota and Guam
Status: Endangered
Habitat: Primarily mature limestone forest, but also ultilizes secondary forest, coastline forest, ravine forest, agriculutral forest, and coconut plantations.
Nesting: Generally occurs in the drier season (i.e. September to March). Nests are typically contructed in the inner forest canopy and are composed of a large platform with intermediate and inner cups made from vines and twigs. Nests have been recorded in over 20 tree species.
Diet: Omnivorous, consisting mostly of small invertebrates and fruit. Diet includes Lepidopteran larvae, grasshppers, mole crickets, praying mantis, earwigs, and hermit crabs, and forages on trees' foliage, fruit, seeds, and buds, including breadfruit, figs, and papaya. Also eats small verterbrates (e.g. skinks, geckos, small rats) and bird eggs.
Rota White-eye
Zosterops rotensis

Range: Rota
Status: Critically Endangered
Habitat: Primarily limestone forests in areas greater than 150m above sea-level. Also observed in thickets of introduced Acacia, Leucaena, and bamboo.
Nesting: Observed from December through August, but breeding may occur year-round. Nests are cup-like and generally suspended between branches and branchlets or leaf petioles, and have been found in Hernandia, Merrilliodendron, and Elaeocarpus.
Diet: Primarily insects, fruits, and nectar.

Mariana Fruit-dove
Ptilinopus roseicapilla

Range: Rota, Saipan, Agiguan, Tinian
Status Protected in the CNMI. Common on islands it occurs.
Habitat: Forest canopy.
Nesting: Nest is a small, loose collection of twigs built on tree branches.
Diet: Seeds and fruit, especially figs.

Micronesian Honeyeater
Myzomela rubratta saffordi

Range: Rota, Saipan
Status: Common to abundant
Habitat: Lowland habitats such as forest edge, roadsides, and plantations.
Nesting: A very small cup built with spider webs, grass, roots, and ironwood tree needles.
Diet: Nectar from hibiscus, coconuts, and other plants.

Rufous Fantail
Rhipidura rufifrons mariae

Range: Commonwealth of Northern Mariana Islands
Status: Common
Habitat: Native forests and tangantangan.
Nesting: A cone-shaped nest built within 10 feet of the ground.
Diet: Insects.

Micronesian Starling
Apolonis opaca

Range: Rota, Aguigan, Tinian, and Saipan.
Status: Abundant
Habitat: Most habitats from seacoast to mountaintop.
Nesting: Built in hollowed out areas in coconut palms or other trees. Will sometimes nests in limestone cliff cavities or in holes in wooden telephone poles.
Diet: Fruits, seeds and insects.

Collared Kingfisher
Halcyon chloris orii

Range: Mariana islands
Status: Widespread
Habitat: Wide-ranging, often perches on powerlines.
Nesting: Often nest in tree cavities or holes in limestone cliffs.
Diet: Small animals including insects, birds, and mammals.

White-throated Ground-dove
Gallicolumba xanthonura

Range: Mariana Islands
Status: Uncommon
Habitat: Mainly in forests, clearings along roadsides, and plantations.
Nesting: A framework of twigs built high in tree branches.
Diet: Fruits, seeds, flowers.

White Tern (or Fairy Tern)
Gygis alba

Range: Mariana Islands
Status: Common
Habitat: Nests and roost in dense forest (where available) or low vegetation on atolls.
Nesting: Do not build a nest. Instead, they lay a single egg on a bare tree branch.
Diet: Fish and squid.

Yellow Bittern
Ixobrychus sinensis

Range: Mariana Islands
Status: Fairly common
Habitat: Forages in dense vegation or at edge of forests, shrubby thickets and wetlands.
Nesting: A variety of locations, such as in low shrubs on offshore islets, in trees, and among grasses at freshwater wetlands.
Diet: Small insects and other small animals.

Pacific Reef Heron
Egretta sacra

Range: Mariana islands
Status: Common
Habitat: Forages on exposed reef and mudflats, taro patches, ponds, and inland streams.
Nesting: Nests in small groups inland in trees or on rock ledges.
Diet: Small aquatic prey.

Guam Rail
Rallus owstoni Ko'ko'

Range: Experiemental population on Rota since 1995. Captive breeding population on Guam.
Status: Critically endangered.
Habitat: Shrubby areas in fields and forest edges.
Nesting: Lays four eggs in a shallow nest on the ground.
Diet: Omnivorous. Eats seeds, insect, grubs, snails, skinks and geckos.

Recommended reading: Jenkins, J.M. 1979. Natural history of the Guam Rail. Condor 81:404-408.



Wedge-tailed Shearwater, Puffinus pacificus
White-tailed Tropicbird(pictured), Phaethon lepturus
Red-tailed Tropicbird, Phaethon rubricauda
White-tailed Tropicbird, Phaethon lepturus
Masked Booby, Sula dactylatra
Red-footed Booby, Booby Sula sula
Brown Booby, Sula leucogaster
Great Frigatebird, Fregata minor
Lesser Frigatebird, Fregata ariel
Brown Noddy, Anous stolidus
Introduced Birds

Rota is home to several species of introduced birds including:
Black Drongo(pictured), Dicrurus macrocercus, native to SE Asia and Australasia.
Island Collared Dove, Streptopelia bitorquata, native to the Philippines, introduced in 1700's.
Eurasian Tree-sparrow, Passer montanus, spread over most of Europe and Siberia.
Rock Pigeon, Columbia livia, introduced worldwide, originally from southern and western Europe, north Africa and SW Asia.
Red Junglefowl, Gallus gallus, introduced worldwide, originally from southern and western Europe, north Africa and SW Asia.


Gadwall, Anas strepera
Mallard, Anas platyrhynchos
Eurasian Widgeon, Anas penelope
Northern Pintail, Anas acuta
Northern Shoveler, Anas clypeata
Garganey, Anas querquedula
Green-winged Teal, Anas crecca
Common Pochard, Aythya ferina
Tufted Duck, Aythya fuligula
Greater Scaup, Aythya marila
Gray Heron, Ardea cinerea
Great Egret, Ardea alba
Intermediate Egret, Egretta intermedia
Little Egret, Egretta garzetta
Cattle Egret, Bubulcius ibis
Striated Heron, Butorides striata
Black-crowned Night-Heron, Nyticorax nycticorax
Osprey ,Pandion haliaetus
Black Kite, Milvus migrans
Chinese Sparrowhawk , Accipiter soloensis
Eurasian Kestrel, Falco tinnunculus
Peregrine Falcon, Falco peregrinus
Black-bellied Plover, Pluvialis squatarola
Pacific Golden-Plover, Pluvialis fulva
Lesser Sand-Plover, Charadrius mongolus
Greater Sand-Plover, Charadrius leschenaultii
Snowy Plover, Charadrius alexandrinus
Common Ringed Plover, Charadrius hiaticula
Little Ringed Plover, Charadrius dubius
Black-winged Stilt, Himantopus himantopus
Common Greenshank, Tringa nebularia
Marsh Sandpiper, Tringa stagnatilis
Common Redshank, Tringa totanus
Wood Sandpiper, Tringa glareola
Wanderling Tattler, Heterosceles incanus
Gray-tailed Tattler, Heterosceles brevipes
Common Sandpiper, Actitis hypoleucos
Terek Sandpiper, Xenus cinereus
Little Curlew, Numenius minutus
Whimbrel(pictured), Numenius phaeopus
Bristle-thighed Curlew, Numenius tahitiensis
Eastern Curlew, Numenius madagascariensis
Eurasian Curlew, Numenius arquata
Black-tailed Godwit, Limosa limosa
Ruddy Turnstone, Arenaria interpres
Great Knot, Calidris tenuirostris
Sanderling, Calidris alba
Red-necked Stint, Calidris ruficollis
Long-toed Stint, Calidris subminuta
Pectoral Sandpiper, Calidris melanotos
Sharp-tailed Sandpiper, Calidris acuminata
Dunlin, Calidris alpina
Ruff, Philomachus pugnax
Long-billed Dowitcher, Limnodromus scolopaceus
Swinhoe's Snipe, Gallinago megala
Common Snipe, Gallinago gallinago
Oriental Pratincole, Glareola maldivarum
Black-headed Gull, Larus ridibundus
Common Tern, Sterna hirundo
Little Tern, Sterna albifrons
Spectacled Tern, Sterna lunata
Sooty Tern, Sterna fuscata
White-winged Tern, Chlidonias leucopterus
Whiskered Tern, Chlidonias hybridus
Short-eared Owl, Asio flammeus
Fork-tailed Swift, Apus pacificus
Barn Swallow, Hirundo rustica

Above birds reported as migrants within the Commonwealth of Northern Mariana Islands by Wiles, C.J. 2005. A Checklist of the Birds and Mammals of Micronesia. Micronesica 38(1):141-189
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