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T.K. Pratt

Publications and source records attributed to T.K. Pratt.

17 recordsLinked to original sources
USGS2009

Recent status and trends of the land bird avifauna on Saipan, Mariana Islands, with emphasis on the endangered Nightingale Reed-warbler Acrocephalus luscinia

The avifauna of the Mariana Islands, an archipelago in the western Pacific, faces the threats of rapid economic development and the spread of non-native species, particularly a devastating predator, Brown Tree Snake Boiga irregularis. In this paper, we examine the status and trends of the land bird fauna of Saipan Island based on three island-wide surveys conducted in 1982, 1997, and 2007. During this period, the human population on Saipan increased more than four-fold and much of the island has been developed. The surveys employed standard point-transect methods based on Distance Sampling. Remarkably, we found nearly all species of land birds - 11 native species and three introduced species - to be common or abundant. The exception was the Micronesian Megapode Megapodius laperouse, a historically rare species that was not observed on the 2007 survey, although it does persist on Saipan and other Mariana islands. A comparison of species densities among the three surveys showed that seven species, mainly fruit and seed-eaters, had increased and three species of insectivorous birds had decreased - Rufous Fantail Rhipidura rufifrons, Nightingale Reed-warbler Acrocephalus luscinia, and Golden White-eye Cleptornis marchei. Of these three, Nightingale Reed-warbler is listed as Endangered on the IUCN Red List and as an Endangered Species by the U.S. Fish and Wildlife Service. Reed-warbler densities on Saipan decreased by more than half between 1982 and 2007. Although point transect sampling worked well for this species, density estimates and trends assessment could be improved by reallocating sampling stations among habitats and by more frequent sampling. ?? BirdLife International 2009.

Bird Conservation International↗
USGS2006

Plant phenology in a cloud forest on the island of Maui, Hawaii

We recorded the times of flowering, fruiting, and leafing for ten native canopy and subcanopy trees and shrubs (monthly from December 1994 through December 1997) in a montane cloud forest with relatively aseasonal rainfall on the island of Maui, Hawaii. These species represented the great majority of individual woody plants at the site. Flowers and fruits were available in the community year–round; however, all species exhibited annual patterns of flowering, and four species showed annual patterns of fruiting while the rest fruited in supra–annual patterns. Many species had protracted flowering or fruiting peaks, and some bore small numbers of flowers or fruit year-round. Most species flowered in a monthly peak mainly between May and August, corresponding to the period of greatest solar irradiance and marginally higher temperatures. Fruit ripening followed at varying intervals. In contrast, the heaviest flowering occurred between November and March, resulting from bloom of the dominant tree, Metrosideros polymorpha. At the highest elevations, Metrosideros flowering was heaviest during September, but peak flowering of lower elevation trees occurred in late fall and winter. Two forms of this species differed in their temporal and spatial patterns of flowering. For M. polymorpha var. polymorpha and var. incana , bloom peaked annually between November and January; however, for M. polymorpha var. glaberrima , flowering peaked from April through July, with an earlier secondary peak in January.

Hawai'i↗
USGS2004

Prevalence and differential host-specificity of two avian blood parasite genera in the Australo-Papuan region

The degree to which widespread avian blood parasites in the genera Plasmodium and Haemoproteus pose a threat to novel hosts depends in part on the degree to which they are constrained to a particular host or host family. We examined the host distribution and host-specificity of these parasites in birds from two relatively understudied and isolated locations: Australia and Papua New Guinea. Using polymerase chain reaction (PCR), we detected infection in 69 of 105 species, representing 44% of individuals surveyed (n = 428). Across host families, prevalence of Haemoproteus ranged from 13% (Acanthizidae) to 56% (Petroicidae) while prevalence of Plasmodium ranged from 3% (Petroicidae) to 47% (Ptilonorhynchidae). We recovered 78 unique mitochondrial lineages from 155 sequences. Related lineages of Haemoproteus were more likely to derive from the same host family than predicted by chance at shallow (average LogDet genetic distance = 0, n = 12, P = 0.001) and greater depths (average distance = 0.014, n = 11, P < 0.001) within the parasite phylogeny. Within two major Haemoproteus subclades identified in a maximum likelihood phylogeny, host-specificity was evident up to parasite genetic distances of 0.029 and 0.007 based on logistic regression. We found no significant host relationship among lineages of Plasmodium by any method of analysis. These results support previous evidence of strong host-family specificity in Haemoproteus and suggest that lineages of Plasmodium are more likely to form evolutionarily-stable associations with novel hosts.

Molecular Ecology↗
USGS2003

Phylogeny of the owlet-nightjars (Aves: Aegothelidae) based on mitochondrial DNA sequence

The avian family Aegothelidae (Owlet-nightjars) comprises nine extant species and one extinct species, all of which are currently classified in a single genus, Aegotheles. Owlet-nightjars are secretive nocturnal birds of the South Pacific. They are relatively poorly studied and some species are known from only a few specimens. Furthermore, their confusing morphological variation has made it difficult to cluster existing specimens unambiguously into hierarchical taxonomic units. Here we sample all extant owlet-nightjar species and all but three currently recognized subspecies. We use DNA extracted primarily from museum specimens to obtain mitochondrial gene sequences and construct a molecular phylogeny. Our phylogeny suggests that most species are reciprocally monophyletic, however A. albertisi appears paraphyletic. Our data also suggest splitting A. bennettii into two species and splitting A. insignis and A. tatei as suggested in another recent paper. ?? 2003 Elsevier Science (USA). All rights reserved.

Molecular Phylogenetics and Evolution↗
USGS2002

Temporal variation in bird counts within a Hawaiian rainforest

We studied monthly and annual variation in density estimates of nine forest bird species along an elevational gradient in an east Maui rainforest. We conducted monthly variable circular-plot counts for 36 consecutive months along transects running downhill from timberline. Density estimates were compared by month, year, and station for all resident bird species with sizeable populations, including four native nectarivores, two native insectivores, a non-native insectivore, and two non-native generalists. We compared densities among three elevational strata and between breeding and nonbreeding seasons. All species showed significant differences in density estimates among months and years. Three native nectarivores had higher density estimates within their breeding season (December-May) and showed decreases during periods of low nectar production following the breeding season. All insectivore and generalist species except one had higher density estimates within their March-August breeding season. Density estimates also varied with elevation for all species, and for four species a seasonal shift in population was indicated. Our data show that the best time to conduct counts for native forest birds on Maui is January-February, when birds are breeding or preparing to breed, counts are typically high, variability in density estimates is low, and the likelihood for fair weather is best. Temporal variations in density estimates documented in our study site emphasize the need for consistent, well-researched survey regimens and for caution when drawing conclusions from, or basing management decisions on, survey data.

Hawaii↗
USGS2001

`Akohekohe response to flower availability: seasonal abundance, foraging, breeding, and molt

We studied the relationship of flower availability to the seasonality of life history events of the `Akohekohe (Palmeria dolei), a primarily nectarivorous and endangered Hawaiian honeycreeper from montane rain forests on Maui, Hawai`i. For comparison, we also investigated temporal bird density and foraging behavior of three other competing Hawaiian honeycreepers: `Apapane (Himatione sanguinea), `I`iwi (Vestiaria coccinea), and Hawai`i `Amakihi (Hemignathus virens). All species except `Amakihi fed primarily on nectar of `Ohi?a-lehua (Metrosideros polymorpha), which produced flowers year-round but had an annual flowering peak in January. Flowers of several subcanopy shrubs and trees were important components of the diet for all nectarivores, and these were available seasonally depending upon the species. `Akohekohe densities did not change temporally, suggesting a relatively stable population residing above 1,700 m. Monthly densities of `Apapane, `I`iwi, and Hawai`i `Amakihi were positively correlated with monthly `Ohi?a-lehua flower abundance, and 50-80% of these populations departed temporarily from our high-elevation site in July. There was a positive correlation with the timing of Akohekohe breeding and high abundance of `Ohi?a-lehua bloom. Molt followed breeding. From a conservation perspective, these results show that `Akohekohe maintain a relatively stable population above the mid-elevation zone of disease transmission, particularly during the fall when `Ohi?a-lehua bloom decreases and mosquitoes increase. `Akohekohe remain on their territories partly by switching their foraging to subcanopy trees and shrubs, most of which require protection from feral pigs (Sus scrofa).

Hawaii↗
USGS2000

Evidence for a previously unrecognized species of owlet-nightjar

I studied the systematic relationships of the three large owlet-nightjars (Aegothelidae) to determine the taxonomic status of a fawn-colored lowland form currently classified as Aegotheles insignis tatei. I examined most of the existing specimens of A. i. insignis ( n = 158) and A. crinifrons ( n = 23) and all known specimens of A. i. tatei ( n = 4). I also examined specimens of A. albertisi ( n = 70), A. archboldi ( n = 25), A. bennettii ( n = 55), A. cristatus ( n = 50), A. savesi ( n = 1), and A. wallacii ( n = 21). Aegotheles i. tatei was distinguishable from A. i. insignis and A. crinifrons by its small size and in seven plumage characters. Aegotheles i. tatei was further distinguishable from one or the other of these taxa by four additional characters. Unique among owlet-nightjars, A. i. tatei has the shortest tarsi, does not have recurved filamentous tips on its facial feathers, and has stiffer feathers on the auricular area and throat. My search of museums revealed two new specimens of A. i. tatei, expanding the known geographic range of this taxon 1,000 km eastward along the southern coast of Papua New Guinea from the upper Fly River to Nunumai, near the Ulamanu River. Unlike the montane A. i. insignis, A. i. tatei inhabits lowland forests where rivers emerge from foothills of the main cordillera. I propose that tatei be elevated to species status and that the name Starry Owlet-Nightjar be adopted based on the bird's markings. Aegotheles crinifrons, A. insignis, and A. tatei pass through a previously unrecognized but distinctive rufous juvenal plumage. These are the only owlet-nightjars known to exhibit this plumage, which calls for reexamination of generic limits within the Aegothelidae.

The Auk↗
USGS1996

Description of adults, eggshells, nestling, fledgling, and nest of the poo-uli

The Poo-uli (Melamprosops phaeosoma), a Hawaiian honeycreeper discovered on the island of Maui in 1973 and now near extinction, is represented in museums by only two specimens. Based on the first observations of a nesting pair and re-examination of the two specimens, we describe the adult male and female, eggshells, nestling, and fledgling Poo-uli. Poo-uli are sexually monochromatic but males are brighter. The male is brown above, whitish below, and has an extensive black mask bordered with gray on the crown and a distinct white auricular patch. The female differs in having a similar facial pattern not as sharply demarked and in having a grayish wash below. The observed fledgling resembled the adults but was paler brown above and whitish below and had a much smaller black mask and pale mandible. We tentatively assigned both museum specimens to first basic plumage because they resembled the adult female but retained some pale juvenal coloration in the mandible. We also determined from dissection that the holotype was an immature male; we could not determine sex of the paratype. The nest was an open cup of twigs and bryophytes with a thin lining of fern rootlets. The nest contained eggshell fragments with brown-gray speckling against a whitish background. The nests, eggshells, and nestlings resemble those of other Hawaiian honeycreepers.

The Wilson Bulletin↗
USGS1996

Nesting behavior of the poo-uli

We describe two sequential nestings of a pair of Poo-uli (Melamprosops phaeosoma), a Hawaiian honeycreeper nearing extinction. Similarities to nesting of most other honeycreepers included: nest site in ohia lehua (Metrosideros polymorpha Gaud.) canopy; breeding in March through June; monogamous breeding system with the putative male helping build the nest, feeding the putative female throughout each nesting event, and feeding the chicks, but not incubating or brooding; and complete nest sanitation. Notable differences were the paucity of songs and calls by the parents and inclusion of snails in the diet of nestlings. Clutch size was probably two eggs for both nests. High winds, rain, or both influenced parental behavior: the female stayed longer on the nest and took shorter recesses in poor weather. Weather did not affect rates at which the male fed the female on the nest; however, the feeding rate increased from the egg to the chick stage probably because food was passed on to the chicks. At nest #2, parents fed young chicks (<14 days old) more often in good than in poor weather; data were insufficient for old chicks. Weather is usually poor throughout the year in the relictual range of the Poo-uli and is likely to impact nesting success. The first nest failed in poor weather. The second fledged a single young 21 days old. Diet of nestlings appeared to consist of a higher proportion of insect larvae than that of older birds, which are reported to eat mostly snails.

The Wilson Bulletin↗
USGS1994

Identifying sex and age of akiapolaau

Methods for identifying the sex and age of the Akiapolaau (Hemignathus munroi), an endangered honeycreeper found only on the island of Hawaii, were developed by examination and measurement of 73 museum specimens and 24 live birds captured in mist nests. Akiapolaau probably undergo a single annual molt, with most birds molting between February and July. The mottled juvenal plumage is replaced by a first basic plumage characterized by yellowish-gray or yellowish-green underparts and often by retained wingbars. Male Akiapolaau may not attain adult plumage until their third molt. In adult females, only the throat and upper breast become yellow, whereas in adult males the superciliaries, cheeks, and entire underparts are yellow. Adult males have greater exposed culmen, gonys, wing chord, tail, and tarsus lengths than do females. Akiapolaau in first prebasic molt or older can be identified as to sex by culmen length, that of males being >23.4 mm.

The Wilson Bulletin↗
USGS1993

Identifying sex and age of apapane and iiwi on Hawaii

Methods to determine the sex and age of Apapane (Himatione sanguinea) and Iiwi (Vestiaria coccinea) were developed on the basis of 189 museum specimens and 91 live birds captured in mist nets on the Island of Hawaii (USA). Both species retain all juvenal primaries and some juvenal secondaries and body feathers after the first prebasic molt and attain full adult plumage after the second prebasic molt. Apapane in their first basic plumage retain some buff-edged juvenal secondaries (particularly secondaries five and six) and sometimes retain a few gray-brown feathers on the head. The first basic plumage of Iiwi is characterized by secondaries 6-9 being longer and darker than secondaries 1-4 and the presence of a few yellowish juvenal body feathers with black spots at the tips. Adult male Apapane and Iiwi have longer wing, tail, exposed culmen, culmen and tarso-metatarsus lengths than females. Linear discriminant functions are presented to sex adult Apapane and Iiwi from lengths of their wing chord and exposed culmen.

Journal of Field Ornithology↗
USGS1993

Sex and age identification of palila

Methods to sex and age Palila (Loxioides bailleui), an endangered Hawaiian finch restricted to subalpine woodlands on Hawai'i, were identified on the basis of measurements and plumage characteristics of 17 museum specimens and 96 known-age, live Palila. Palila undergo a single annual molt during September-December following the breeding season. Presence of a complete or partial wingbar distinguishes hatch-year and second-year Palila from after-second-year birds. Adult male Palila are distinguished from females by a distinct napeline and lt 30% gray feathers intermixed with yellow feathers on the head. The black or gray feathers of the lores and chin of males are darker than those on the back, whereas the lores and chin of females are lighter or of the same shade as back feathers.

Journal of Field Ornithology↗