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Paul C. Banko

Publications and source records attributed to Paul C. Banko.

68 records · Page 4Linked to original sources
USGS2006

Factors related to the recovery of subalpine woodland on Mauna Kea, Hawaii

We measured mature tree and sapling density, tree associations, crown size, age structure, recovery from ungulate browsing, and grass cover at four study sites in two types of subalpine woodland on Mauna Kea volcano, island of Hawaii. Beginning in 1981, introduced ungulates were reduced in number to allow regeneration of Sophora chrysophylla (mamane) in habitat supporting the endangered Hawaiian finch, Loxioides bailleui (palila). We found Sophora regeneration at all four study sites, but regeneration was higher in mixed species woodland with codominant Myoporum sandwicense (naio) than in areas where Sophora dominated. Regeneration of Myoporum was uniformly very low in comparison. Invasive grass cover, which suppresses Sophora germination, was highest in mid-elevation woodland where Sophora dominated. The distribution of mature and sapling Sophora were both related to study site, reflecting previous ungulate browsing and uneven recovery due to grasses. Densities of Sophora snags were not different among any of the sites, suggesting a more even distribution in the past. Selective browsing before ungulate reduction may have favored Myoporum over Sophora , leading to high densities of mature Myoporum in codominant woodland. After ungulate reduction, however, we found no pattern of competitive inhibition by Myoporum on regeneration of Sophora . Reduction of Myoporum is not likely to enhance habitat for Loxioides as much as supplemental planting of Sophora , grass control, and continued ungulate eradication. Mid-elevation Sophora woodland areas, where Loxioides forage and nest in high densities, would benefit the most from these management actions.

Hawai'i↗
USGS2006

Long-term population monitoring: Lessons learned from an endangered passerine in Hawai‘i

Obtaining reliable population estimates is crucial to monitoring endangered species and developing recovery strategies. The palila ( Loxioides bailleui ) is an endangered seed-eating Hawaiian honeycreeper restricted to the subalpine forests of Mauna Kea, a volcano on the island of Hawai‘i, USA. The species is vulnerable to extinction primarily because >90% of the population is concentrated in <30 km 2 of habitat on the western slope of this high, dormant volcano. Annual surveys of the palila population have been conducted for ecological, legal, and other purposes since 1980. Because refinements to sampling protocols and analytical methods have evolved, we examined means of adapting the monitoring program to produce comparable estimates of abundance over the past 25-year period and into the future. We conducted variable circular plot surveys during the nonbreeding season (Jan–Mar) and this used data to obtain estimates of effective detection radius and annual density with Distance 4.0, Release 2. For comparability over the time-series, we excluded from analysis the data from new transects. We partitioned the 25-year data set (1980–1996 and 1997–2004) into 2 separate analyses because, beginning in 1997, observers received more training to reduce their tendency to estimate distances to 5-m intervals. We used geographic strata in the analysis of recent surveys because changes in habitat may have invalidated the density-based strata used previously. By adding observer and year and observer and time of day as co-variables, we improved the model fit to the 2 data sets, respectively. Annual estimates were confounded by changes in sampling methodology and analytical procedures over time. However, the addition of new transects, increased training for observers, and use of exact distance estimates instead of rounding also improved model fit. Habitat characteristics and behavior of palila that potentially influenced detection probability, sampling, analysis, and interpretation were regeneration of trees in response to reduced numbers of introduced browsing mammals, seasonally variable rates of vocalization, non-territoriality, and resource-tracking along an elevation gradient. We believe our adaptive approach to analysis and interpretation of 25 years of annual variable circular plot data could help guide similar long-term monitoring efforts.

Hawai'i↗
USGS2006

Feral Cats: Too Long a Threat to Hawaiian Wildlife

BACKGROUND Domestic cats (Felis catus) were first brought to Hawai`i aboard sailing ships of European explorers and colonists. The job of these predators was to control mice and rats on the ships during the long voyages. As in other places, cats were taken in and adopted by the families of Hawai`i and soon became household pets known as popoki. But cats have always been very well equipped to live and hunt on their own. On tropical archipelagos like the Hawaiian Islands where no other predatory mammals of comparable size existed, abundant and naive prey were particularly easy game, and cats soon thrived in the wild. Although the details of when cats first came to live in the wild remain little known, adventurers, writers, and naturalists of the day recorded some important observations. Feral cats were observed in remote wilderness around K?ilauea volcano on Hawai`i Island as early as 1840 by explorer William Brackenridge. Mark Twain was so impressed by the great abundance of cats when he visited Honolulu in 1866 that he reported his observations in the Sacramento Union newspaper, which were later reprinted in his book Roughing It: I saw... tame cats, wild cats, singed cats, individual cats, groups of cats, platoons of cats, companies of cats, regiments of cats, armies of cats, multitudes of cats, millions of cats...

Fact Sheet↗
USGS2006

Food specialization and radiation of Hawaiian honeycreepers

Hawaiian honeycreepers are renowned for adaptive radiation and diet specialization. Specialization arose from competition for the relatively few resources available in this remote archipelago and because arthropod prey sufficient to satisfy nestling protein requirements could only be captured by highly modified bills. Historically, most species fed their nestlings with larvae of the widespread geometrid moth genus, Scotorythra ; but other invertebrates were important also. Thus the palila, Loxioides bailleui , a specialist on potentially toxic Sophora chrysophylla seeds, feeds its nestlings on Cydia moth larvae found inside Sophora seeds. Sophora seeds are also fed to the nestlings, and seed availability largely determines the timing and extent of breeding. By this and other means, food specialization contributed to reproductive isolation in Loxioides and possibly other honeycreepers. Alien threats to insect prey affect Loxioides populations and have hastened the extinction or decline of other specialized Hawaiian birds

Acta Zoologica Sinica↗
USGS2002

Palila ( Loxioides bailleui )

One of the last surviving of the extraordinary “finch-billed” Hawaiian honeycreepers (Drepanidinae), the Palila epitomizes specialization for seed-eating as it relies almost entirely on immature (soft) seeds, flowers, and other resources produced or supported by mämane ( Sophora chrysophylla : Fabaceae), an endemic dry-forest tree. Mämane seeds are highly nutritious, but a strong, sharp bill is necessary to remove and rip open the tough, fibrous pods that protect them. In addition, the seeds contain high levels of potentially toxic secondary compounds, which may also explain why they are eaten by so few other native or alien species. The Palila's close association with mämane influences not only its foraging behavior but also its distribution, abundance, dispersal, and breeding ecology. Like most drepanidines, the Palila produces small clutches, usually only 2 eggs. However, Palila embryos and chicks develop slowly, so eggs and nestlings are threatened by storms and predators for a longer time than many other small passerine species.

Birds of North America↗
USGS2001

Conservation status and recovery strategies for endemic Hawaiian birds

Populations of endemic Hawaiian birds declined catastrophically following the colonization of the islands by Polynesians and later cultures. Extinction is still occurring, and recovery programs are urgently needed to prevent the disappearance of many other species. Programs to recover the endemic avifauna incorporate a variety of conceptual and practical approaches that are constrained by biological, financial, social, and legal factors. Avian recovery is difficult to implement in Hawai‘i because a variety of challenging biological factors limit bird populations. Hawaiian birds are threatened by alien predatory mammals, introduced mosquitoes that transmit diseases, alien invertebrate parasites and predators that reduce invertebrate food resources, and alien animals and plants that destroy and alter habitats. Life in the remote Hawaiian Archipelago has imposed other biological constraints to avian recovery, including limited geographical distributions and small population sizes. Recovery of the endemic avifauna is also challenging because resources are insufficient to mitigate the many complex, interacting factors that limit populations. Decisions must be made for allocating limited resources to species teetering on the brink of extinction and those in decline. If funds are spent primarily on saving the rarest species, more abundant species will decline and become more difficult to recover. However, critically rare species will disappear if efforts are directed mainly towards restoring species that are declining but not in immediate danger of becoming extinct. Determining priorities is difficult also because management is needed both to supplement bird populations and to restore habitats of many species. Rare species cannot respond quickly to management efforts intended only to improve habitat and reduce limiting factors. Recovery is slow, if it occurs at all, because years or decades are generally required for habitat rehabilitation and because small populations of birds initially increase slowly even when habitat conditions are favorable. Consequently, even as habitat conditions begin to improve, small populations may disappear unless they are supplemented directly. Hawaiian bird conservation is also affected by social and legal factors, including hunting alien game species, commercial land use practices, and lawsuits and policies concerning endangered species and critical habitat. Influenced by this mixture of conflicting and competing issues, Hawaiian bird recovery programs range from management of single species and some components of their habitats to limited forms of community or ecosystem management. Although the effectiveness of most programs is difficult to evaluate because of monitoring limitations, several programs exemplify species and community management. Programs primarily intended to recover single species include Hawaiian Goose or Nene ( Branta sandvicensis ), Hawaiian Crow or ‘Alala ( Corvus hawaiiensis ), and Palila ( Loxioides bailleui ). Programs attempting to manage entire communities of forest birds include Hakalau Forest National Wildlife Refuge and Hawai‘i Volcanoes National Park on Hawai‘i, and Waikamoi Preserve, Hanawi Natural Area Reserve, and Haleakala National Park on Maui.

Hawaii↗
USGS2001

Drepanidine movements in relation to food availability in subalpine woodland on Mauna Kea, Hawai'i

Flowers of the mamane tree ( Sophoru chrysophylla ) are the primary nectar source for Hawaiian honeycreepers in subalpine woodland on Mauna Kea Volcano on the island of Hawai‘i. Mamane seeds are the primary food resource of the endangered Palila ( Loxioides bailleui ), which is now restricted to subalpine woodland on Mauna Kea. The objectives of this study were to determine the patterns and relative scales of movements of the drepanidine community in relationship to food availability and tree density on leeward Mauna Kea. ‘I‘iwi ( Vestiaria coccinea ) and ‘Apapane ( Himatione sanguinea ) densities were related to mamane flower abundance. Palila densities were related to mamane pod abundance. These species also had higher densities in mamane woodland than in naiomamane woodland, unlike the more insectivorous Hawai‘i ‘Amakihi ( Hemignathus virens ) whose densities did not differ between woodland types. Palila and Hawai’i ‘Amakihi do not make movements on the same scale as ‘I‘iwi and ‘Apapane, whose densities changed by more than an order of magnitude. Ungulate eradication, grass reduction, tire management, and restored corridors of mamane woodland would benefit all drepanidines on Mauna Kea, particularly the Palila.

Hawai'i↗
USGS2000

Consequences of antenna design in telemetry studies of small passerines

Entanglement and mortality of Palila ( Loxioides bailleui ), an endangered Hawaiian honeycreeper, occurred when birds were radio-tagged with transmitters equipped with a long, limp, solder-tipped antenna. Birds were found suspended in trees by their transmitter antenna on eight occasions. Although these birds eventually freed themselves or were freed by us, at least one bird died afterwards. For radio telemetry studies of small passerine species we recommend avoiding transmitters equipped with an antenna that is bulbous at the tip, >16 cm in length, limp, and shiny.

Journal of Field Ornithology↗
USGS1999

Hawaiian Goose ( Branta sandvicensis )

Evolving in the remote Hawaiian Archipelago and having the smallest range of any living goose, the Hawaiian Goose, or better known by its Hawaiian name—Nënë, is among the most isolated, sedentary, and threatened of waterfowl. The Nënë is also highly terrestrial, and several structural features demonstrate its adaptation to life on islands with limited freshwater habitat: It stands taller and more upright than geese of similar weight, enabling it to reach high to browse the fruits, seeds, and foliage that constitute its herbivorous diet; its legs and padded toes are long and strong, promoting swift, sure walking and running over rugged terrain; webbing is reduced between the toes; and though it is a capable swimmer and readily uses freshwater habitats when available, the Nënë does not require freshwater or oceanic habitats in the same way that many other waterfowl do.

Birds of North America↗
USGS1999

Survival and physiologic response of common Amakihi and Japanese white-eyes during simulated translocation

We evaluated the effects of three translocation trials on Common Amakihi (Hemignathus virens) and Japanese White-eyes (Zosterops japonicus). Trial 1 involved capturing birds, transporting them on rough roads for 4 hr followed by holding in an aviary for 48 hr without overnight thermal support prior to release. Trial 2 involved capture, then holding in an aviary for 48 hr with overnight thermal support followed by transport for 4 hr prior to release. Trial 3 and 1 were identical except that overnight thermal support was provided during trial 3. We monitored survival, food consumption, weight change, and fecal production during captivity as well as changes in hematocrit, estimated total solids, heterophil to lymphocyte ratios, plasma uric acid, and creatinine phosphokinase (CPK) at capture and release. Survival was significantly lower for Amakihi during trial 1 (no thermal support). Birds that died lost significantly more weight than those that survived. Regardless of trial, birds responded to translocation by a combination of weight loss, anemia, hypoproteinemia, and elevated heterophil to lymphocyte ratio, uric acid, and CPK levels. The first 24 hr of captivity posed the greatest risk to birds regardless of whether transport or holding occurred first. Food consumption, fecal production, and weight all decreased at night, and overnight thermal support during holding was critical if ambient temperatures dipped to freezing. We recommend that if small passerines are to be held for > 12 hr, they be monitored individually for weight loss, food consumption, and fecal production.

The Condor↗
USGS1998

Nonindigenous Ants at High Elevations on Mauna Kea, Hawai'i

Ant surveys were conducted at high elevations (1680-3140 m) on the western slope of Mauna Kea Volcano on the island of Hawai'i to detennine the extent of ant infestation in those highland communities and particularly to evaluate the potential threat of ants in the highlands to native Hawaiian species. Ants were surveyed at 10 long-tenn sampling sites. Ants were common on Mauna Kea up to 2000 m elevation, but densities quickly dropped off above that. Five species of ants were collected: Linepithema humile (Mayr), Cardiocondyla venustula Wheeler, Pheidole megacephala (Fabricius), Tetramorium bicarinatum (Nylander), and Monomorium pharaonis (Linnaeus). Other than L. humile , these collections on Mauna Kea are the highest recorded locales in the Hawaiian Islands.

Hawaii↗
USGS1997

Status and management of the PaliIa, an endangered Hawaiian honeycreeper, 1987-1996

A single, relictual population of Palila Loxioides bailleui, a Hawaiian honeycreeper, survives on the slopes of Mauna Kea volcano on the island of Hawai'i, where it feeds principally on flowers and green seeds of the mamane tree Sophora chrysophylla. The Palila was listed as an endangered species by state and federal governments because of continuing damage to its habitat by browsing Feral and Mouflon Sheep Ovis aries and O. musimon and Goats Capra hircus and because of the bird's restricted range and low numbers. Ecology of the Palila was studied from 1987 to 1996. Annual population estimates fluctuated between 1 600 and 5 700 and averaged 3 400 birds. Estimates varied with availability of mamane seeds, which are less abundant in drought years. In drought years, most birds did not attempt to breed, and survival rates were lower because of a shortage of food. Availability of mamane seeds also showed large seasonal variability. While some nests were preyed upon by Owls Asio flammeus, Cats Felis catus and Rats Rattus rattus, losses were high at the end of the season from unexplained death of eggs and chicks. Genetic studies did not implicate inbreeding depression. Neither avian malaria nor avian pox appeared at this site, where the mosquito vector was absent. However, weather and food shortage worsened towards the end of the nesting season. Availability of food and habitat remain the principal factors limiting increase in the Palila population. Recovery efforts now focus on reducing numbers of feral ungulates, fire management, removing mammalian predators, and developing techniques for captive propagation and introduction to currently unoccupied sites within the bird's former range. Reforestation adjacent to the Mauna Kea Forest Reserve would allow the Palila population to expand and grow.

Pacific Conservation Biology↗