Pacific Science Volume 51, Number 1, 1997

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Pacific Science is a quarterly publication devoted to the biological and physical sciences of the Pacific Region.


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    A New Approach for Analyzing Bird Densities from Variable Circular-Plot Counts
    (University of Hawaii Press, 1997-01) Fancy, Steven G.
    An approach for calculating bird densities from variable circular-plot counts is described. The approach differs from previous methods in that data from several surveys are pooled and detection distances are adjusted as if all distances were recorded by a single observer under a given set offield conditions. Adjustments for covariates that affect detection distances such as observer, weather, time of day, and vegetation type are made using coefficients calculated by multiple linear regression. The effective area surveyed under standard conditions is calculated from the pooled data set and then used to determine the effective area surveyed at each sampling station under the actual conditions when the station was sampled. The method was validated in two field studies where the density of birds could be determined by independent methods. Computer software for entering and analyzing data by this method is described.
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    Radar Study of Seabirds and Bats on Windward Hawai'i
    (University of Hawaii Press, 1997-01) Reynolds, Michelle H. ; Cooper, Brian A. ; Day, Robert H.
    Modified marine surveillance radar was used to study the presence/ absence, abundance, and flight activity of four nocturnal species: Hawaiian darkrumped petrel [Pterodroma phaeopygia sandwichensis (Ridgeway)], Newell's shearwater [Puffinus auricularis newelli (Henshaw)], Band-rumped storm-petrel [Oceanodroma castro (Harcourt)), and Hawaiian hoary bat (Lasiurus cinereus semotus Sanborn & Crespo). Hawaiian seabirds were recorded flying to or from inland nesting colonies at seven sampling sites on the windward side of the island of Hawai'i. In total, 527 radar "targets" identified as petrel or shearwater-type on the basis of speed, flight behavior, and radar signal strength were observed during eight nights of sampling. Mean movement rates (targets per minute) for seabird targets were 0.1, 0.1,0.3, 3.8, 0.9, and 2.2 for surveys at Kahakai, Kapoho, Mauna Loa, Pali Uli, Pu'ulena Crater, and Waipi'o Valley, respectively. Two percent of the petrel and shearwater-type targets detected on radar were confirmed visually or aurally. Flight paths for seabird targets showed strong directionality at six sampling sites. Mean flight speed for seabird targets (n = 524) was 61 km/hr for all survey areas. Peak detection times for seabirds were from 0430 to 0530 hours for birds flying to sea and 2000 to 2150 hours for birds returning to colonies. Most inland, low elevation sampling sites could not be surveyed reliably for seabirds during the evening activity periods because of radar interference from insects and rapidly flying bats. At those inland sites predawn sampling was the best time for using radar to detect Hawaiian seabirds moving seaward. Hawaiian hoary bats were recorded at eight sampling sites. Eighty-six to 89 radar targets that exhibited erratic flight behavior were identified as "batlike" targets; 17% of these batlike radar targets were confirmed visually. Band-rumped storm-petrels were not identified during our surveys.
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    A New Genus and Species of Lizard (Reptilia: Scincidae) from New Caledonia, Southwest Pacific
    (University of Hawaii Press, 1997-01) Sadlier, Ross A. ; Bauer, Aaron M.
    An unusual new lygosomine skink, Simiscincus aurantiacus Sadlier & Bauer, n. sp., is described from a single specimen collected in southern New Caledonia. This species is a member of the Eugongylus group of skinks, but is not readily assignable to any known genus. It has a number of derived characteristics that serve to distinguish it, the most notable of which is the highest number of premaxillary teeth of any scincid. Although its relationships cannot, at present, be established unambiguously, it appears to share affinities with another monotypic endemic New Caledonian genus, Graciliscincus. The discovery of this species highlights the extreme diversity and endemicity of the New Caledonian lizard fauna.
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    The Terrestrial Herpetofauna of the Loyalty Islands
    (University of Hawaii Press, 1997-01) Sadlier, Ross A. ; Bauer, Aaron M.
    The terrestrial herpetofauna of the Loyalty Islands, New Caledonia, is reviewed. This is the first comprehensive account of the reptile fauna of these islands since Roux's monograph on the region in 1913 and is based on recent collections made in August 1987 and a review of the collections made by Roux and Sarasin and housed in the Naturhistorisches Museum, Basel. Seventeen species of lizards and two species of snakes (one boid and one typhlopid) occur in the Loyalty Islands. Approximately half the lizard species are endemic to the New Caledonia/Loyalty Islands region, but only one, Emoia loyaltiensis (Roux), is endemic to the Loyalties alone. The remaining lizard species have widespread distributions throughout the Pacific. Most widespread species also occur on mainland New Caledonia, but several (Gehyra vorax Girard, Emoia cyanura [Lesson], and Candoia bibroni [Dumeril & Bibron]) do not.
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    Sea-Floor Geology of a Part of Mamala Bay, Hawai'i
    (University of Hawaii Press, 1997-01) Hampton, Monty A. ; Torresan, Michael E. ; Barber, John H Jr.
    We surveyed the sea-floor geology within a 200-km2 area of Mamala Bay, off Honolulu, Hawai'i, by collecting and analyzing sidescan sonar images, 3.5kHz profiles, video and still visual images, and box-core samples. The study area extends from 20-m water depth on the insular shelf to 600-m water depth in a southeast-trending trough. The sidescan images depict three principal types of seafloor material: low-backscatter natural sediment, high-backscatter drowned carbonate reef, and intermediate-backscatter dredged-material deposits. Cores indicate that the natural sediment is muddy sand, composed of carbonate reef and microfauna debris with some volcanic grains. Vague areal trends in composition are evident. The dredged material comprises poorly sorted, cobble- to clay-size mixtures of reef, volcanic, and man-made debris, up to 35 cm thick. Dredged-material deposits are not evident in the 3.5-kHz profiles. In the sidescan images they appear as isolated, circular to subcircular imprints, apparently formed by individual drops, around the periphery of their occurrence, but they overlap and coalesce to a nearly continuous, intermediate-backscatter blanket toward the center of three disposal sites investigated. We did not observe noticeable currents during our camera surveys, but there is abundant evidence of sediment reworking: symmetrical and asymmetrical ripples in the visual images, sand waves in the 3.5-kHz profiles and side-scan images, moats around the reefs in 3.5-kHz profiles, winnowed dredged material in the visual images, and burial of dredged material by natural sediment in cores. Most current indicators imply a westerly to northwesterly transport direction, along contours or upslope, although there are a few areas of easterly indicators. Internal waves probably drive the transport; their possible existence is implied by measured water-column density gradients.
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