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Many seabird breeding colonies have recovered from heavy anthropogenic disturbance after conservation actions. The widely distributed red-tailed tropicbird, Phaethon rubricauda, was used as a model species to assess potential anthropogenic impacts on the genetic diversity of breeding colonies in the Pacific Ocean. Cytochrome c oxidase subunit I and control region sequences analyses were conducted across the range of the species in the Pacific Ocean. The study sites were at islands without human-related disturbance (non-impacted islands) and with human-related disturbance (impacted islands). We hypothesized that (i) breeding colonies of the red-tailed tropicbird on impacted islands have lower genetic diversity compared with colonies on non-impacted islands, and (ii) breeding colonies of the red-tailed tropicbird show significant fine and broad-scale genetic structure across the Pacific Ocean. Bayesian skyline analyses were conducted to infer past changes in population sizes. Genetic diversity was similar between impacted and non-impacted islands. There was significant broad-scale genetic structure among colonies separated by over 6,000 km, but a lack of significant fine-scale genetic structure within Australasia and Hawai'i, although a significant level of differentiation was found within Chile with ΦST analyses. Skyline analyses showed that effective population sizes remained relatively constant through time, but experienced either a slight decrease or the end of an expansion event through the last 1,000 years. These changes may be related to the arrival of humans on Pacific islands. Impacted islands may have received immigrants from other relatively close islands, buffering the loss of genetic diversity. However, it is also possible that colonies have retained ancestral variation or that a large effective population size coupled with a long generation time (13 years) has prevented the loss of genetic diversity in human-impacted islands. Future research using higher-resolution markers is needed to resolve the population genetic structure of the red-tailed tropicbird in an ecological time-scale.

Globally, seabirds are vulnerable to anthropogenic threats both at sea and on land. Seabirds typically nest colonially and show strong fidelity to natal colonies, and such colonies on low-lying islands may be threatened by sea-level rise. We used French Frigate Shoals, the largest atoll in the Hawaiian Archipelago, as a case study to explore the population dynamics of seabird colonies and the potential effects sea-level rise may have on these rookeries. We compiled historic observations, a 30-year time series of seabird population abundance, lidar-derived elevations, and aerial imagery of all the islands of French Frigate Shoals. To estimate the population dynamics of 8 species of breeding seabirds on Tern Island from 1980 to 2009, we used a Gompertz model with a Bayesian approach to infer population growth rates, density dependence, process variation, and observation error. All species increased in abundance, in a pattern that provided evidence of density dependence. Great Frigatebirds (Fregata minor), Masked Boobies (Sula dactylatra), Red-tailed Tropicbirds (Phaethon rubricauda), Spectacled Terns (Onychoprion lunatus), and White Terns (Gygis alba) are likely at carrying capacity. Density dependence may exacerbate the effects of sea-level rise on seabirds because populations near carrying capacity on an island will be more negatively affected than populations with room for growth. We projected 12% of French Frigate Shoals will be inundated if sea level rises 1 m and 28% if sea level rises 2 m. Spectacled Terns and shrub-nesting species are especially vulnerable to sea-level rise, but seawalls and habitat restoration may mitigate the effects of sea-level rise. Losses of seabird nesting habitat may be substantial in the Hawaiian Islands by 2100 if sea levels rise 2 m. Restoration of higher-elevation seabird colonies represent a more enduring conservation solution for Pacific seabirds. Resumen: Globalmente, las aves marinas son vulnerables a amenazas antropogenicas tanto en el mar como en tierra. Las aves marinas tipicamente anidan en colonias y muestran alta fidelidad a las colonias natales, y tales colonias en islas de baja elevacion pueden ser amenazadas por el incremento del nivel del mar. Utilizamos French Frigate Shoals, el mayor atolon en el Archipielago Hawaiano, como un estudio de caso para explorar la dinamica poblacional de colonias de aves marinas y los efectos potenciales que puede tener el incremento del nivel del mar sobre estas colonias. Compilamos observaciones historicas, una serie de tiempo de 30 anos de la abundancia de poblaciones de aves marinas, elevaciones e imagenes aereas de todas las islas de French Frigate Shoals. Para estimar la dinamica poblacional de 8 especies de aves marinas que se reprodujeron en la Isla Tern de 1980 a 2009, utilizamos un modelo Gompertz con un metodo Bayesiano para inferir las tasas de crecimiento poblacional, la densodependencia, la variacion del proceso y el error de observacion. Todas las especies incrementaron en abundancia, en un patron que proporciono evidencia de la densodependencia. Es probable que Fregata minor, Sula dactylatra, Phaeton rubricauda, Onychoprion lunatus y Gygis alba se encuentren en capacidad de carga. La densodependencia puede exacerbar los efectos del incremento del nivel del mar sobre aves marinas porque las poblaciones cercanas a la capacidad de carga en una isla seran mas afectadas que poblaciones con espacio para crecer. Proyectamos que 12% de French Frigate Shoals se inundara si el nivel del mar incrementa 1 m y 28% si el nivel del mar incrementa 2 m. Onychoprion lunatus y especies que anidan en arbustos son especialmente vulnerables al incremento del nivel de mar, pero diques y la restauracion de habitat pueden mitigar los efectos del incremento del nivel del mar. Las perdidas de habitat para la anidacion de aves marinas puede ser sustancial en las Islas Hawaianas en 2100 si el nivel del mar incrementa 2 m. La restauracion de colonias de aves marinas en sitios mas elevados representa una solucion mas perdurable para la conservacion de aves marinas del Pacifico.

During spring and autumn 1980-95, we surveyed Red-tailed Phaethon rubricauda, White-tailed P. lepturus and Red-billed Tropicbirds P. aethereus at sea in the Pacific between the coast of the Americas and 176°W. For the Pacific, we had complete coverage of the range of aethereus, but only partial coverage of that of rubricauda and lepturus. Six areas of higher density were indicated: three of rubricauda, two of lepturus and one of aethereus. After pooling data across years, the 'abundance' (total number including subadults and adults) estimate for rubricauda was 81 700 (boreal spring) and 86 500 (boreal autumn) birds. Abundance of each of the three rubricauda subpopulations differed between seasons by about 50% despite seasonal consistency when populations were grouped. Furthermore, high densities of rubricauda occurred at the edge of our study area, indicating that neither of the seasonal estimates for this species could be considered as total numbers. Abundance estimates of lepturus during the non-breeding season (when these birds had dispersed from colonies) were 11 000 and 41 500 birds for northern and southern populations, respectively. Estimated abundance of aethereus during the boreal spring was 26 700 birds, and 33 400 during the boreal autumn. Because tropicbirds are attracted to survey vessels, we also estimated the abundance after excluding those recorded as flying in a steady direction, or having been attracted to the ship. Considering only stationary birds (i.e. those that could not have been attracted), our minimum estimates were 41 000 rubricauda, 15 750 aethereus, 28 000 southern lepturus and 6400 northern lepturus.

We reviewed the status of the breeding marine birds on San Benedicto Island, Mexico, based on >100 years of published observations and seven of our own surveys conducted between 1978 and 2000. We found that there have been marked changes in the island avifauna with two main trends evident. First, a volcanic eruption destroyed much of the island in 1952. The Wedge-tailed Shearwater (Puffinus pacificus; estimated breeding population 1,000 pairs), Townsend's Shearwater (Puffinus auricularis; probable breeder, small numbers), and Red-footed Booby (Sula sula; 60 pairs) historically had much larger populations, but they apparently never fully recovered from the eruption. The Masked Booby (Sula dactylatra; 2,185 pairs), however, has become much more abundant perhaps due to changes in the vegetation. The second trend is that within the last three decades at least two, and possibly four, species from the central Pacific have colonized the island. The Laysan Albatross (Phoebastria immutabilis; 12 pairs) started breeding in the late 1980s; Black-footed Albatross (Phoebastria nigripes; 1 pair) in 2000. Red-tailed Tropicbirds (Phaethon rubricauda; probable breeder, 10 pairs) may have started breeding in the 1980s, and at least some of the breeding Brown Boobies (Sula leucogaster; 300 pairs) are from central Pacific populations. The reason(s) for this influx of central Pacific species is unknown, but likely involves changes in the marine environment. Other breeding species include the Red-billed Tropicbird (Phaethon aethereus; 200 pairs), Nazca Booby (Sula granti; 50 pairs), Great Frigatebird (Fregata minor; 165 pairs), and Magnificent Frigatebird (Fregata magnificens; 5 pairs).

We examined nest sites of Red-tailed Tropicbirds (Phaethon rubricauda) on Rose Island of the Rose Atoll National Wildlife Refuge, American Samoa, to determine habitat features important for nest-site selection of this species. We quantified habitat characteristics at 27 nest sites and at 27 random sites during September 1991. All nests were located under beach heliotrope (Messerschmidia argentea) shrubs or pisonia (Pisonia grandis) trees. Nest sites were placed farther under the nest shrub, had more stems in the nest space, and greater percent shade cover than random sites. Nest sites averaged 24.9 m from their nearest neighbor, ≥20 m greater than has been reported elsewhere for this colonial species. We suggest that an overpopulation of Polynesian rats (Rattus exelans) may have influenced nest-site selection by Red-tailed Tropicbirds on Rose Island.

From 1990 to 2000, the Johnston Atoll Chemical Agent Disposal System (JACADS) incinerated part of the U.S. stockpile of chemical weapons on Johnston Atoll, central Pacific Ocean, which also is a National Wildlife Refuge and home to approximately a half-million breeding seabirds. The effect on wildlife of incineration of these weapons is unknown. Using a multi-strata mark-recapture analysis, we investigated the effects of JACADS on reproductive success, survival, and movement probabilities of red-tailed tropicbirds (Phaethon rubricauda) nesting both downwind and upwind of the incineration site. We found no effect of chemical incineration on these tropicbird demographic parameters over the 8 years of our study. An additional 3 years of monitoring tropicbird demography will take place, post-incineration.

The fauna of Chile's Sala y Gomez island (26028'S, 105021'W) is not well known because of the island's remote location, small size, and low profile. Previous literature about the bird life of this island consists of one report based on two visits of less than three hours duration, listing 11 species of seabirds, of which seven were observed breeding. The authors of the present study remained on the island for six days, during which time we observed 14 species of birds, ten of which were nesting. Both species richness and abundance were greater than reported previously. Sala y Gomez Island has significant breeding colonies of Blue-gray Noddy (Procelsterna cerulea) and Christmas Shearwater (Puffinus nativitatis). Also we recorded for the first time nesting by small numbers of Redbilled Tropicbirds (Phaethon aethereus) and White Terns (Gygis alba). Received 29 September 1998, accepted 2 December 1998. Resumen.-La fauna que habita en la isla Sala y Gomez (26028'S, 105021'W), Chile, es escasamente conocida debido a lo remoto de esta isla, su pequefio tamafio y baja altitud. Sobre sus aves s61o existe un reporte que da cuenta de dos visitas de menos de tres hr de duraci6n. Esta nota describe la presencia de 11 especies de aves marinas, siete de ellas nidificantes. Durante nuestro estudio nosotros permanecimos seis dias en la isla, registrando 14 especies de aves, con 11 especies nidificantes. Tanto la riqueza, como las abundancias registradas por nosotros fueron mayores a las mencionadas por el reporte anterior. La isla Sala y Gomez posee importantes poblaciones reproductivas de Procelsterna cerulea y Puffinus nativitatis. Ademas en ella nidifican Nesofregettafuliginosa, Sula dactylatra, Phaethon rubricauda, Anous stolidus y Sterna fuscata. Ademais registramos por primera vez la nidificaci6n de Phaethon aethereus y Gygis alba, pero en bajo nimero.

This paper represents part of a study on the thermoregulatory responses of nesting sea birds to natural environmental conditions. The investigations were conducted on Midway Island. Our previous publications (Howell and Bartholomew, 1961a, 1961b) have dealt with Laysan and Black-footed albatrosses (Diomedea immutabilis and D. nigripes), Bonin Island Petrels (Pterodroma hypoleuca), and Wedge-tailed and Christmas Island shearwaters (Pufinus pacificus and P. nativitatis). Bailey (1956) gives a useful account of the natural history of these and other species found on Midway. In the course of visits to Midway Island in June and July, 1959 and 1960, we were able to obtain data on thermoregulation in the Red-tailed Tropic Bird (Phaethon rubricauda) and the Red-footed Booby (Sula sula). Aside from the work of Probine and Wodzicki (1955) on the Gannet (Sula bassana) and that of Bartholomew, Dawson, and O'Neill (1953) and Bartholomew and Dawson (1954) on pelicans (Pelecanus), we know of no quantitative studies on thermoregulation in pelecaniform birds.

Described are 6 new species: Schoengastia pobsa from nesting area, seabirds, and European rabbit; Schoengastia saurella from lizards, Cryptoblepharus boutoni and Lepidodactylus lugubris; Microtrombicula nesiota from Sula dactylata; Toritrombicula gygis from Gygis alba; Toritrombicula oceanica from Pluvialis dominica; Toritrombicula thalassa from Nesofregetta albigularis. New host and locality records are given for Blankaartia amersoni, Neoschoengastia atollensis, N. carveri, N. ewingi, N. nr. gallinarum (with description and comments), N. namrui, Neoschoengastoides nr. archaea, Guntherana domrowi, and Guntherana sp. Brennan (1965) identified four species of chiggers in a meager 12 collections from a few seabirds and lizard on four islands of the north central Pacific. Described were Blankaartia amersoni and Guntherana domrowi, and listed were Schoengastia philipi (here revealed to be a new species) and a lone specimen of the peculiar Womersia strandtmanni, a first and only record of its occurrence in the Pacific. This report derives from 111 lots of chiggers collected as that part of the Smithsonian Institution's Pacific Ocean Biological Survey Program to determine species, numbers, host associations, and ecology of all ectoparasites of terrestrial vertebrates in the primary area of interest. General collections were made from 96 host species on 42 islands. Chiggers were identified from 17 hosts plus man (one specimen attached) on 15 islands and three positions at sea, the 18 locations lying within approximately 26? N to 12? S and 167? E to 159? W. Fifteen species including six new are recorded. Sixteen species of chiggers in seven genera are now recognized in the central Pacific. Schoengastia pobsa sp. n. (Fig. 1) Type data: Holotype and 3 paratypes, RML 46987, larvae, from nesting area, McKean Island, 1 May 1966, N. Heryford; 9 paratypes off Psittarostra cantans, Laysan Island, 11 June 1966, Amerson; 4 paratypes off Phaethon rubricauda and 1 off Puffinus nativitatis, Phoenix Island, 15 April 1966, Heryford; 8 paratypes off Oryctolagus cuniculus, Phoenix Island, 26 May 1965, Amerson. Received for publication 18 May 1971. Holotype and some paratypes in the Rocky Mountain Laboratory, other paratypes in the National Museum of Natural History, Bishop Museum, British Museum (Natural History), and Field Museum of Natural History. Diagnosis: S. pobsa and the following species, S. saurella, superficially resemble S. philipi Womersley and Kohls (off skink, Goodenough Island, New Guinea) but are distinguished by 2 mastitarsalae III and dorsal formula 2-10-8-8-6-2, 1 mastitarsala III and 2-8-6-6-4-2 in S. philipi. Body: Ovate, length and width of holotype, unfed, 215 by 110' u. Eyes 2/2, in a plate, diameter of anterior eye, 8 Am. Anus between fourth and fifth rows of ventral setae. Gnathosoma: Mildly punctate. Cheliceral blades with tricuspid cap and a row of 4 to 6 small dorsal teeth. Galeal seta nude. Palpal setae B/N/NNB, rarely the genual with 1 or 2 branches; tarsus with 7 branched setae, a subterminala and a tarsala; tibial claw trifurcate. Scutum: As figured. With deeply convex and mildly sinuous posterior margin and sinuous anterior margin. Sparsely punctate. Sensillae broadobovate, their bases barely posterior to posterolateral setae. AM less than half as long as the subequal AL and PL. Scutal measurements of holotype: AW 49, PW 67, SB 17, ASB 17, PSB 22, AP 20, AM 28, AL 61, PL 62, S 22 X 13. Legs: Moderately to sparsely punctate. Specialized setae as figured: 3 genualae I, genuala II and III, tibiala III, 2 nude mastitarsalae III. Nonspecialized setae heavily to sparsely branched. Coxal III seta anteromediomarginal. Leg index 660 (sum of lengths of legs I to III on one side). Body setae: Dorsal setae arranged 2-10-8-8-6-2; humerals 41 Au, posthumerals 26 to 40 A, becoming smaller posteriorly. Ventral setae 2-2 sternals plus 28 to 32, postanals similar to dorsals. Schoengastia saurella sp. n. Type data: Holotype and 7 paratypes, RML 45540, larvae, off Cryptoblepharus boutoni, Baker Island, 9 July 1963 (this series was referred to