THE AVIFAUNA OF FARALLON DE MEDINILLA, MARIANA ISLANDS

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THE AVIFAUNA OF FARALLON DE MEDINILLA, MARIANA ISLANDSAuthor(s): Michael R. Lusk, Phillip Bruner, and Curt KesslerSource: Journal of Field Ornithology, 71(1):22-33. 2000.Published By: Association of Field OrnithologistsURL: http://www.bioone.org/doi/full/10.1648/0273-8570-71.1.22

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FIELD ORNITHOLOGYFriday Oct 19 2001 03:26 PM 2000Allen Press • A V i i O N System

forn 71_103 Mp_23File # 03ds

23

J. Field Ornithol., 71(1):22–33

THE AVIFAUNA OF FARALLON DE MEDINILLA, MARIANAISLANDS

MICHAEL R. LUSK1

U.S. Fish and Wildlife ServicePacific Islands Ecoregion, 300 Ala Moana Blvd.

Room 3-122, Box 50088, Honolulu, Hawaii 96850 USA

PHILLIP BRUNERBiology Department, Box 1775

Brigham Young University, Hawaii CampusLaie, Hawaii 96762 USA

CURT KESSLER2

Division of Fish and Wildlife, Lower BaseP.O. Box 10007, Saipan

Commonwealth of the Northern Mariana Islands 96950 USA

Abstract.—Farallon de Medinilla is a small island in the western Pacific that is leased by theU.S. military from the Commonwealth of the Northern Mariana Islands as an impact areafor training exercises. We spent 5.5 h on the island surveying its avifauna on 4 Nov. 1996and observed a total of 17 species including seabirds, migratory shorebirds, and residentlandbirds. Of special interest was the first island record of the endangered MicronesianMegapode (Megapodius laperouse) and breeding colonies of Great Frigatebirds (Fregata mi-nor) and Masked Boobies (Sula dactylatra). Locations of individual megapodes and seabirdcolonies were mapped and breeding information recorded. Historical records and photo-graphs indicate that since the island has been used as an impact area its vegetative structurehas changed from a medium-height, relatively closed canopy forest, to primarily open areaswith intermittent patches of low forest. Alterations of native vegetation likely resulted inchanges in the density, distribution, and species composition of the island’s avifauna, al-though these changes are difficult to quantify.

LA AVIFAUNA DEL FARALLON MEDINILLA, ISLAS MARIANAS

Sinopsis.—El Farallon Medinilla es una pequena isla en el Pacıfico occidental que perteneceal Estado Libre Asociado de las Marianas del Norte y es arrendada al ejercito de los EstadosUnidos para hacer practicas de bombardeo. Visitamos dicha isla el 4 de noviembre de 1996y en 5.5 hrs. logramos observar 17 especies de aves. De especial interes fue el primer informede colonias reproductivas de Fregata minor y Sula dactylatra. Ademas se observaron individuosde Megapodius laperouse, especie que se considera en peligro de extincion. Los informes yfotografias historicas indican que desde que la isla esta siendo utilizada para practicas debombardeo, ha cambiado la estructura de la vegetacion de una de mediana altura y de docelcerrado a areas abiertas con parches intermitentes de bosque bajo. La alteracion de la ve-getacion nativa aparentemente ha ocasionado cambios en la composicion, densidad, y dis-tribucion de las especies de aves, auque dichos cambios son dificiles de cuantificar.

The Mariana Island archipelago comprises the 14-island U.S. Common-wealth of the Northern Mariana Islands (CNMI) and the Territory ofGuam. The 15 islands extend 750 km from 138149N, 1448459W to 20839N,

1 Current address: Piedmont National Wildlife Refuge, 718 Juliette Road, Round Oak, Georgia31038 USA.2 Current address: P.O. Box 31132, Flagstaff, Arizona 86003 USA.

M. R. Lusk et al.24] J. Field Ornithol.Winter 2000



1448549W, lying about 1500 km east of the Philippines and 1600 km southof Japan. The climate is tropical, with daily mean temperatures of 24–32C and average annual rainfall of 200–260 cm.

Because of the strategic importance of the Mariana Islands, the U.S.military maintains a large presence on Guam, and leases almost two-thirdsof the island of Tinian in the CNMI (Belt Collins 1994). The island ofFarallon de Medinilla (FDM) has been leased from the CNMI for use asa bombing range by the U.S. military since at least 1971 (USDN 1975).In 1983 a 50-yr lease, with an option to renew for another 50 yr, wasnegotiated between the CNMI and the U.S. government for military useof FDM (USA 1983).

Because of FDM’s remote location and status as an active impact area,changes in the flora and fauna of FDM as the result of military activityhave been difficult to monitor. Access to FDM is restricted by the militarydue to the presence of unexploded ordnance, which is sometimes coveredby thick vegetation. Therefore we report the results of the first on-the-ground visit to the island by biologists in 25 yr.

STUDY AREA

Approximately 248 km northeast of Guam, FDM (168019N, 1468049E)is the sixth island in the Mariana archipelago. Like the five islands to itssouth, it is composed primarily of limestone, while the remaining north-ern islands are volcanic. FDM measures 2.6 3 0.4 km, with a surface areaof 0.9 km2 (Fig. 1). The island is generally flat, but slopes gradually fromeast to west, with the highest point reaching 82 m. The southern third ofthe island is a narrow peninsula separated from the main body of theisland by a partially collapsed isthmus. The entire island is surroundedby steep seacliffs, particularly on the east side, which make access by boatexceptionally difficult. There are two small beaches (Fig. 1), both ofwhich are overwashed during periods of high tide.

Currently, the island is dominated by open areas composed of grasses,herbaceous species, and thickets of crinum lilies (Crinum asiaticum)(Whistler 1996). There are no trees or shrubs greater than 2 m in heightand woody vegetation, consisting mainly of Pisonia grandis, is restrictedto a few small protected pockets. A more thorough description of thecurrent vegetation of FDM may be found in Whistler (1996).

METHODS

On 4 Nov, 1996 we were transported to FDM by helicopter and madewildlife observations from 0730 to 1300 h. We walked the perimeter ofthe main body of the island and crossed the central interior (Fig. 1). Themajority of the island’s interior is inaccessible due to heavy groundcoverthat hides unexploded ordnance. We recorded species of birds present,their location, estimated numbers, and evidence of breeding activity. Thesouthern third of the island is inaccessible from the north, therefore es-timates of seabirds in this area were made during helicopter over-flight.

We reviewed historical accounts and photographs of FDM and com-

Vol. 71, No. 1 [25Avifauna of Farallon de Medinilla



FIGURE 1. Map of Farallon de Medinilla showing survey route, sea caves, and locations ofMicronesian Megapodes.




pared historical conditions of vegetation and avifauna with present con-ditions. We interviewed Bob Moncrief who visited FDM in 1974 whileemployed by the U.S. Navy as a marine biologist (Eldredge 1983; B. Mon-crief, Ecologist, U.S. Army Corps of Engineers, pers. comm.). Most of theinformation in USDN (1975) came from that visit, but Moncrief was ableto provide additional information not found there. As part of our inter-view with Moncrief, he reviewed a video taken during our visit and com-pared it to his memory of conditions in 1974.

In addition to our observations, we summarized the results of surveyssince 1979. All of these surveys were based on boat observations only.

RESULTS

Avian Species Accounts

There are now a total of 23 avian species recorded from FDM, includingfive species reported for the first time in this paper.

Wedge-tailed Shearwater (Puffinus pacificus).—This species is consid-ered an uncommon visitor (Reichel 1988, Reichel and Glass 1991). Al-though we did not see shearwaters, a cluster of three burrow entranceswas discovered in the bare soil along the eastern edge of the island. Theburrows had the general shape and size appropriate for Wedge-tailedShearwaters, but could have been made by Polynesian rats (Rattus exu-lans), coconut crabs (Birgus latro), or Micronesian Megapodes (Megapo-dius laperouse), all of which are present on the island.

Red-tailed Tropicbird (Phaethon rubricauda).—Pratt and Lemke (1984)saw five birds flying over the island and up to 10 breeding pairs have beenestimated for the island (Pratt 1985; Reichel 1988, 1991). We saw fourbirds flying over the island. We were not able to confirm breeding, butit may occur along the steep sea cliffs surrounding the island.

White-tailed Tropicbird (Phaethon lepturus).—A population of up tofive breeding pairs has been previously estimated (Pratt and Lemke 1984;Pratt 1985; Reichel 1988, 1991). We did not encounter this species.

Masked Booby (Sula dactylatra).—Fritz (1902) described large numbersof seabirds nesting on trees, shrubs, and on bare ground. The seabirdsdescribed as nesting on bare ground were likely Masked Boobies. Thisspecies was first identified on FDM by Hachisuka et al. (1932). Baker(1951) referred to Yamashina’s (1932) report of 12 eggs taken from FDMin 1931. USDN (1975) recorded this species as being present, but did notgive a population estimate. USDN (1975) also stated that boobies nestedevenly over the vegetated top of the island at a density of about 247 nestsper ha and estimated a population of 50,000 adult boobies, with manymore juveniles in addition. They did not specify if this estimate was forall species of boobies or one particular species. Pratt (1985) estimated atotal population of 200 Masked Boobies and confirmed nesting. Pratt andLemke (1984) added that birds were seen roosting and nesting on barrenareas of the east coast and southern isthmus. Later, 40–50 breeding pairswere estimated for the entire island (Reichel 1988, 1991).




During our survey of the island, we estimated 750 Masked Boobies. Breed-ing was confirmed by the presence of several nests with one or two eggs pernest, a nest with one downy-chick, and several family groups with immaturebirds (one immature per breeding pair). Nests and family groups were pri-marily concentrated on bare hardpan soil along the eastern rim of the mainbody of the island, although some were found at the southern tip (Fig. 1).Masked Boobies were the most numerous bird species present.

FDM is particularly important for Masked Boobies because it representsthe largest known nesting site for this species in the Mariana Islands.Masked Boobies are believed to breed on only four other Mariana islands,with Maug’s estimated 250 breeding pairs being the second largest colony(Reichel 1991).

Brown Booby (Sula leucogaster).—The description by Fritz (1902) ofboobies nesting on bare ground might also include Brown Boobies. Thisspecies was mentioned by Hachisuka et al. (1932) as occurring on FDMand Baker (1951) referred to Yamashina (1932) who said 12 eggs weretaken from FDM in 1931. USDN (1975) reported Brown Boobies as pre-sent and breeding. Pratt and Lemke (1984) estimated a population of.150 birds, but later as many as 500 breeding pairs were estimated (Pratt1985; Reichel 1988, 1991).

We estimated a population of 200 birds, including a few immature birdsnear fledging, confirming a breeding population. Three or four deadimmature birds were found, and all living immatures appeared emaciated.Brown Boobies were confined to the southeastern corner of the mainisland (Fig. 2). It is possible that more Brown Boobies were roosting andnesting on the steep cliffs.

Red-footed Booby (Sula sula).—Fritz’s (1902) description of seabirdsnesting in great numbers on trees and bushes most likely referred to Red-footed Boobies. This species was reported by Hachisuka et al. (1932) tooccur on FDM, Saipan, and Rota. Baker (1951) mentions this speciesoccurring on FDM and USDN (1975) records it as breeding. Pratt (1985)estimated 1000 birds and confirmed nesting. Pratt and Lemke (1984)added that nesting occurred in small trees on the west side of island, withmany of the nests concentrated on the north end of the island. Reichel(1988, 1991) estimated 200 breeding pairs.

We estimated a population of 500 birds and noted many nests underconstruction, including a few with eggs. No chicks or fledglings were ob-served. Red-footed Boobies were clustered in small colonies found alongthe western edge and southeastern corner of the island, with a largeconcentration of nests near the northern tip (Fig. 2). Birds were roostingand nesting in low shrubby vegetation, predominately P. grandis. One-dark phase bird was seen attending a nest, but the predominate morphwas white-phase, as is common on other islands in the region.

Great Frigatebird (Fregata minor).—It is possible that one of the sea-birds that Fritz (1902) described as nesting on trees and bushes was theGreat Frigatebird. USDN (1975) listed this species as present. Eleven to15 birds have been reported flying around the island, with as many as




FIGURE 2. Map of Farallon de Medinilla showing locations of Masked, Red-footed, andBrown Booby colonies on 4 Nov. 1996.




seven perched in a group (Pratt and Lemke 1984, Reichel 1988). Otherauthors reported this species as only a visitor (Reichel 1988, Reichel andGlass 1991). We discovered a breeding colony on the west-central edgeof the island (Fig. 2). We estimated 25 birds, including several juvenilesroosting with the main colony or flying near shore. Several nests wereobserved, one with a single egg. The nests were constructed in low trees1.5–2.0 m high, similar to those used by Red-footed Boobies. The colonywas clearly separate from, but surrounded by, nesting Red-footed Boobies.Moncrief (pers. comm.) remembered a Great Frigatebird colony of sim-ilar size and location from his 1974 visit. The current colony of GreatFrigatebirds is particularly important as it is one of only two breedingcolonies known to exist in the Mariana Islands (Stinson 1994). The otherbreeding colony exists on Maug (Stinson 1995), which lies approximately450 km northwest of FDM, where only three nestlings/fledglings havebeen observed (Derek Stinson, pers. comm.).

Cattle Egret (Bubulcus ibis).—Pratt et al. (1987) described this speciesas a common migrant to western Micronesia. We saw one bird flyingacross the island near the mixed booby colony (Fig. 2).

Pacific Reef Heron (Egretta sacra).—Pratt and Lemke (1984) reportedone gray-phase reef heron along the shore. Reichel and Glass (1991)listed this species as uncommon with unknown breeding status. We didnot observe this species.

Micronesian Megapode (Megapodius laperouse).—Falanruw (1975) re-ported the known past and present distribution of the megapode to in-clude all of the Mariana islands except FDM. Pratt and Lemke (1984)thought they heard one megapode calling from the northeast end of theisland. Reichel and Glass (1991) listed this bird as hypothetical. We ob-served four birds and two were seen later during a Navy site visit on 17Dec. 1996 (Fig. 1) (USFWS 1998a). All four birds we saw were flushedfrom areas with dense, shrubby vegetation from 1–2 m tall, including C.asiaticum thickets, at the southern end of the main body of the island(Fig. 1). On flushing, the birds called and flew 30–50 m before droppingback into thick vegetation. One bird flushed within 30 m of the burrowsmentioned previously. These burrows were similar to the size and shapeof megapode burrows on other northern Mariana islands, but those bur-rows occurred in looser substrate (D. Stinson, pers. comm.). Although itis possible that nesting does occur on FDM, it is probably not likely dueto the hard packed soil that covers most of the island.

The megapode is a Federally endangered species (USFWS 1970), andthe population archipelago-wide is estimated at between 1440 and 1975birds (USFWS 1998b). Due to its small size FDM would not be capable ofsupporting a large population of megapodes, even if its native vegetationwere in pristine condition. However, the FDM population is valuable inthat it may provide a genetic link between northern and southern popu-lations and the island itself may function as a rest stop for dispersing birds.

Pacific Golden-Plover (Pluvialis fulva).—This species was recorded inUSDN (1975), but Reichel and Glass (1991) listed it as a hypothetical




visitor. We saw five birds in the grassy areas on the main body of the island.Additional birds may have occurred on the southern peninsula wherelower vegetative cover was perhaps more suitable. All of the birds were inbasic plumage.

Wandering Tattler (Heteroscelus incanus).—Pratt and Lemke (1984)flushed two birds from the rocky shoreline. Reichel and Glass (1991)listed this species as an uncommon visitor. We did not observe this species,but did not concentrate our observations on the shoreline areas wherethey had been previously sighted.

Whimbrel (Numenius phaeopus).—This migratory shorebird was re-corded in USDN (1975), but Reichel and Glass (1991) listed it a hypo-thetical visitor. We saw two birds in the central portion of the island, butagain additional birds might have occurred on the more open southernpeninsula.

Bristle-thighed Curlew (Numenius tahitiensis).—This species is a rarevisitor to the Marianas (Stinson et al. 1997). We saw two birds on themain body of the island using areas of low vegetation. This species wasdistinguished by its prominent rusty rump and distinctive call. Both birdswere seen at close range (,50 m) and were heard calling as they flewaround us.

Ruddy Turnstone (Arenaria interpres).—This migratory shorebird iscommon throughout the Pacific (Pratt et al. 1987). We saw two birds ingrassy patches in the central portion of the island.

Sooty Tern (Sterna fuscata).—Pratt and Lemke (1984) reported seeinga pair of birds flying offshore, and Reichel (1988) and Reichel and Glass(1991) list it as a visitor. We saw one bird flying offshore. Although noevidence of nesting was detected, future observers should look for breed-ing activity, as large colonies of Sooty Terns occur on other northernMariana islands (Stinson 1995).

Brown Noddy (Anous stolidus).—This species was listed in USDN(1975). Pratt and Lemke (1984) recorded seeing more than 440 individ-uals and estimated a total population of 1000 birds, but later this estimatewas increased to as many as 3000 birds (Pratt 1985, Reichel 1988). Weestimated a population of 50 birds, with nesting seen inside the large seacave on the east-central edge (Fig. 1). During an aerial survey on 27 May1997, T. W. Sutterfield (pers. comm.) saw what he believed to be BrownNoddies swarming by the thousands. Although this species is generallyflexible in nest sites, using both the ground and trees (Pratt et al. 1987),the birds observed by Sutterfield were nesting in cliff areas.

Black Noddy (Anous minutus).—Pratt and Lemke (1984) reported thisspecies as nesting on the cliffs, sea caves, and possibly the shrubs of FDM,but gave no estimates. Hundreds of breeding pairs were estimated by laterauthors (Pratt 1985; Reichel 1988, 1991). We estimated 20 birds wereusing the sea caves on the east-central edge of island with the BrownNoddies. No breeding was confirmed, but this species will nest both onthe ground or in trees (Pratt et al. 1987), and may breed on FDM.

White Tern (Gygis alba).—This species is recorded as breeding in the




deep limestone caves at the base of the island in USDN (1975), with apopulation estimate of about 1000 birds. Pratt and Lemke (1984) counted31 birds and confirmed breeding by the presence of downy chicks andolder juveniles in one sea cave. Pratt (1985) estimated a population of100 birds and confirmed nesting, while Reichel (1988, 1991) reported 30pairs. We estimated a population of 200 birds. Nesting was confirmed bythe presence of eggs inside the same sea cave on the east central edge ofthe island that was being used by the noddies (Fig. 1). This was the mostabundant tern species seen on or around the island.

Philippine Turtle-Dove (Streptopelia bitorquata).—This non-native spe-cies was recorded by USDN (1975), while Reichel and Glass (1991) list itas a hypothetical breeding resident. We did not encounter this species.

White-throated Ground-Dove (Gallicolumba xanthonura).—This specieswas recorded by USDN (1975). Pratt and Lemke (1984) believed they sawthis species, but could not confirm it. Reichel and Glass (1991) listed itas a suspected resident. We flushed several birds and estimate a maximumpopulation of 50, but did not confirm nesting.

Micronesian Starling (Aplonis opaca).—This species was recorded byUSDN (1975). Pratt and Lemke (1984) tentatively identified two dark birdsseen flying over the island as starlings. Reichel and Glass (1991) listed thisspecies as a hypothetical resident. We did not observe this species.

Eurasian Tree Sparrow (Passer montanus).—This was the only non-na-tive species we recorded. Four birds were seen on the main body of theisland. This species was probably introduced to the Marianas soon afterWW II (Pratt et al. 1987). Tree sparrows occur on Saipan and probablycolonized FDM on their own, but may have been introduced during mil-itary exercises.

Historical Vegetation

Spanish accounts describe FDM as being bare or mostly bare of vege-tation, probably caused by overwash in heavy storms (Corte y Ruano Cal-deron 1875, Sanchez y Zayas 1866, Ibanez y Garcia 1887), but apparentlynone of these descriptions came from an actual landing. Fritz (1902) didland on the island and described it as being vegetated with low trees about4 m high, with patches of grass and lilies. Black and white aerial photo-graphs from the World War II era, both oblique and nadir views, showsmall trees $2 m in height covering approximately 60% of the island’smain body. USDN (1975) reported an overstory of Indian mulberry (Mo-rinda citrifolia) 4 m tall, but also noted that the most abundant groundcover was a coarse sedge and that there were large stands of spider lilies(Pancratium littorale). Several ironwood trees (Casuarina equisetifolia) 3–5 m tall were noted near the north end (B. Moncrief, pers. comm.).Whistler (1996) believed that the 1970s expedition may have misidenti-fied P. grandis as M. citrifolia, and did misidentify C. asiaticum as P. lit-torale. In 1984, CNMI biologists circled the island by boat and character-ized the vegetation as being predominately low in height, but notedpatches of small trees with the greatest concentrations of larger trees on




the north and south ends of the main body of the island (Pratt andLemke 1984). They also noted less than 20% of the island was adequatehabitat for fruit bats, which would roughly correspond to the amount offorested habitat present.

DISCUSSION

The indirect effects of vegetation change, as the result of bombard-ment, have probably had a greater impact on the avifauna of FDM thanthe direct effects of ordnance impacts. Explosions must directly kill birdsand destroy their nests, but once shelling begins, adult and fledged birdslikely abandon the island until the activity has stopped. This would resultin some loss of eggs and chicks, but would mean most adults would likelysurvive to eventually renest. During our landing, we noted that althoughadults were driven from their nests by the arrival of helicopters, someadults returned to their nests within 15 min of cessation of disturbance.

FDM’s vegetation appears to have undergone significant changes sincethe island has been used as an impact area for military training. At theheight of the Vietnam era, as much as 22 tons of ordnance per monthwas delivered to the island (USDN 1975). Over a three year period thatbegan in May 1998, ordnance delivered to the island includes up to: (1)5 to 612 live/inert bombs per month from bombers, (2) 920 missiles and1825 kg of bombs annually from fighter aircraft, (3) 1440 rounds fromnaval gunfire annually, and (4) 50,600 rounds of small caliber ammuni-tion and 2600 grenade rounds annually (USFWS 1998a). The potentialfor this level of military training to alter drastically the vegetation of FDMwas apparent in August 1997 when post-bombardment surveys of FDMrevealed 25–50 fresh bomb craters and a large section of the islandburned to bare earth (USFWS 1998a). It is likely that this type of damageis representative of vegetative change that can occur during military train-ing and demonstrates its potential to alter the vegetative structure of FDMfrom one of a medium-height, relatively closed canopy forest, to one dom-inated by open areas with intermittent patches of low forest. When Fritz’s(1902) descriptions and WW II photos of the island are compared withthe current state of the vegetation, it is obvious that tree height andcanopy cover have been greatly reduced since pre-military use days.

Unfortunately there were no species inventories of FDM’s avifauna until1974 (USDN 1975), and even this list is vague on numbers and distribu-tion. Therefore, although it is probable that changes in FDM’s vegetationhave affected the density, distribution, and species composition of theisland’s avifauna, the extent of these effects is difficult to quantify. Fritz(1902) mentions only great numbers of seabirds but does not identifyspecies. We did not find a deep layer of guano on the ground as Fritz(1902) mentioned, which suggests that numbers of seabirds may havebeen significantly reduced since that time. We know that at least two speciesof boobies were present on FDM from Yamashina’s (1932) collections. Fritz(1902) says there were woodcock, pigeons, and thrushes. ‘‘Pigeons’’ couldrefer to the presence of White-throated Ground-Doves and Philippine Tur-




tle-Doves, but the other species mentioned are difficult to interpret.‘‘Thrushes’’ might refer to Micronesian Starlings, while ‘‘woodcock’’ couldrefer to some shorebirds, such as migratory snipe, or even the MicronesianMegapode. Such limited descriptions of the birds present on FDM priorto its use as a target makes it difficult to compare earlier bird populationson FDM with the degraded conditions that existed by 1974. We speculatethat the presence of more trees with a higher canopy on pre-military useFDM likely resulted in a higher number of tree-nesting landbirds and sea-birds, such as Red-footed Boobies or Common Noddies. Ground-nestingseabirds, such as Masked and Brown Boobies, may now be more commondue to a higher percentage of bare ground and open grasslands.

We believe that neither the vegetation or avian communities havechanged significantly since 1974. Moncrief indicated that the vegetationof the island was essentially the same as it was during his 1974 visit, withlarge areas of lilies and grasses and short, shrubby trees occurring in smallisolated stands. We also believe that the USDN (1975) estimation of ap-proximately 247 nesting pairs of birds per ha, and the estimate of 50,000adult boobies plus juveniles, is probably inflated. Moncrief (pers. comm.)believed that in 1974 seabird densities on FDM were similar, if not slightlylower, than the seabird densities seen in the 1996 video tape. A lowerseabird density estimate also seems more likely when compared to the 4.8breeding pairs of Red-footed Boobies per ha on Maug, the highest densityin the Mariana islands (Reichel 1988).

Despite continuing impacts from military training, FDM remains a valu-able seabird nesting resource in the Marianas and deserves protection. Itis particularly valuable because it possesses important breeding popula-tions of Masked Boobies and Great Frigatebirds. In order to properlyassess the impacts of military training on resident land and seabirds, werecommend that the Navy permit frequent, on-the-ground surveys byqualified biologists. This is the only method by which changes in densities,distribution, and species composition can be adequately monitored overtime. Studies of nest success on FDM compared to other islands wouldalso help to determine affects of military training on resident seabirds.

ACKNOWLEDGMENTS

Funding and transportation for this project was provided by the U.S. Department of theNavy, PACDIVMARIANAS. U.S. Fish and Wildlife Service and Commonwealth of the North-ern Mariana Division of Fish and Wildlife biologists were guests of Belt Collins, Hawaii,Environmental Consulting. We thank Bob Moncrief for sharing his recollections of his 1974trip to FDM and Lou Eldredge for helpful historical information. Belt Collins and TimSutterfield provided historical and recent photographs of, and references for, FDM. BethFlint and Derek Stinson provided input on identification of burrows on FDM. Gary Wilesand David Worthington reviewed early drafts of this paper and provided useful comments.We thank Susan Machida for her help in developing the figures for this paper.

REFERENCES

BAKER, R. H. 1951. The avifauna of Micronesia, its origin, evolution, and distribution. Uni-versity of Kansas Publications, Museum of Natural History 3. 359 pp.

BELT COLLINS. 1994. Environmental Assessment (Second Working Copy)—military exercise,




island of Tinian: Tandem Thrust 95. Prepared for Commander, Pacific Division, NavalFacilities Engineering Command, Pearl Harbor, Hawaii. 248 pp.

CORTE Y RUANO CALDERON, F. 1875. Memoria descriptiva e historica de las islans Mariana yotres. Madrid Imprenta Nacional. [Translation Guam Recorder 3, 1926–1927]

ELDREDGE, L. G. 1983. Summary of environmental and fishing information on Guam andthe Commonwealth of the Northern Mariana Islands: historical background, descriptionof the islands, and review of the climate, oceanography, and submarine topography.NOAA Technical Memorandum NMFS NOAA-TM-NMFS-SWFC-40. 181 pp.

FALANRUW, M. V. C. 1975. Distribution of the Micronesian megapode Megapodius laperousein the northern Mariana Islands. Micronesica 11(1):149–150.

FRITZ, G. 1902. Reise nach den nordlichen Marianen. Mittheilungen aus den deutschenSchtuzgebieten der Sudsee 15:96–118.

HACHISUKA, M. U., N. KURODA, N. TAKASUKASA, S. UCHIDA, AND Y. YAMASHINA. 1932. A listof the birds of Micronesia under Japanese mandatory rule, a handlist of the Japanesebirds, 3rd ed., revised (1942): 167–199. Ornithological Society of Japan.

IBANEZ Y GARCIA, L. 1887. History of the Marianas, Caroline, and Palau Islands. In: MARCEducational Series No. 12, Trans. Marjorie G. Driver. 193 pp.

PRATT, T. K., AND T. O. LEMKE. 1984. Wildlife field trip report from the Townsend CromwellRAIOMA cruise, 18 February–5 March, 1984. CNMI DFW, Saipan, Unpubl. 51 pp.

. 1985. Seabird surveys and inventories. Commonwealth of the Northern MarianaIslands Division of Fish and Wildlife Annual Report FY 1984:69–86. Saipan. Unpubl.

PRATT, H. D., P. L. BRUNER, AND D. G. BERRETT. 1987. A field guide to the birds of Hawaiiand the tropical Pacific. Princeton University Press, Princeton, New Jersey. 409 pp.

REICHEL, J. D. 1988. Seabird surveys and inventories. Commonwealth of the Northern Mar-iana Islands Division of Fish and Wildlife Five-Year Progress Report FY 1983–1987:77–106. Saipan. Unpubl.

. 1991. Status and conservation of seabirds in the Mariana islands. Pp. 248–262, in J.P. Croxall, ed. Seabird status and conservation: a supplement. ICBP Technical Publica-tions, No. 11.

, AND P. O. GLASS. 1991. Checklist of the birds of the Mariana islands. Elepaio 51(1):3–11.

SANCHEZ Y ZAYAS, E. 1866. Voyage of the Spanish corvette ‘‘Narvaez’’ from Manila to theMariana Islands. The Nautical Magazine and Navy Chronicle.

STINSON, D. W. 1994. Birds and mammals recorded from the Mariana islands. Nat. Hist. Res.,Special Issue, No. 1:333–344.

. 1995. Status and conservation of birds in the Mariana islands, Micronesia. Nat. Hist.Res. 3:211–218.

, G. J. WILES, AND J. D. REICHEL. 1997. Occurrence of migrant shorebirds in theMariana Islands. J. Field Ornithol. 68:42–55.

UNITED STATES OF AMERICA, COMMONWEALTH OF THE NORTHERN MARIANA ISLANDS, MARIA-NAS PUBLIC LAND CORPORATION, AND COMMONWEALTH PORTS AUTHORITY. 1983. Leaseagreement made pursuant to the covenant to establish a commonwealth of the NorthernMariana Islands in a political union with the United States of America. 16 pp.

U.S. DEPARTMENT OF THE NAVY. 1975. Final environmental impact assessment, Farallon deMedinilla, bombardment range, Mariana islands. 23 pp. 1 maps and appendices.

U.S. FISH AND WILDLIFE SERVICE. 1970. Conservation of endangered species and other fishand wildlife. Federal Register 35(106):8491–8498.

. 1998a. Biological opinion/conference report of the U.S. Fish and Wildlife Servicefor programmatic aerial bombardment, naval gunfire, and small arms gunfire at Farallonde Medinilla, Commonwealth of the Northern Mariana Islands. 16 pp.

. 1998b. Recovery plan for the Micronesian megapode (Megapodius laperouse lape-rouse). U.S. Fish and Wildlife Service, Portland, Oregon. 651 pp.

WHISTLER, W. A. 1996. Botanical survey of Farallon de Medinilla, Commonwealth of theNorthern Mariana Islands. Report for Belt Collins Hawaii. 20 pp.

YAMASHINA, Y. 1932. On a collection of birds’ eggs from Micronesia. Tori 7:393–413.

Received 8 Sep. 1998; accepted 3 May 1999.

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THE AVIFAUNA OF FARALLON DE MEDINILLA, MARIANA ISLANDS

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