Maui Forest Bird Recovery Project

Makawao, HI, United States

Maui Forest Bird Recovery Project

Makawao, HI, United States
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Dustin Becker C.,Maui Forest Bird Recovery Project | Mounce H.L.,Maui Forest Bird Recovery Project | Rassmussen T.A.,Maui Forest Bird Recovery Project | Rassmussen T.A.,College Place | And 2 more authors.
Endangered Species Research | Year: 2010

The Critically Endangered (IUCN) Maui parrotbill Pseudonestor xanthophrys, an endemic Hawaiian honeycreeper, is restricted to a single population of about 500 individuals. During 3 breeding seasons (2006 to 2008) we found and monitored 17 Maui parrotbill nests from 13 pairs. Eggs and incubating females were confirmed for 12 of the nests, but only 4 fledged successfully. Severe weather led to nest abandonment in 5 cases. Two nests were depredated, and 1 nest had an egg that failed to hatch. Three pairs renested after failures. We used logistic linear regression and ANOVA to evaluate 300 h of observations to assess the effects of parental investment behavior and weather on nest fate. Female time incubating, a significant factor explaining nest fate, did not differ by time of day, but averaged 12 min h-1 less for failed than for successful nests. Male provisioning rates to adult females and chick feeding rates by parents were also significantly related to nest success. Male vocalizations near the nest did not differ by nest fate. Establishment of a second population is a key step in the recovery of Maui parrotbills, and a small captive population has been established. Although limited, our data suggest that collection of Maui parrotbill eggs and/or nestlings up to 1 wk old from nests for captive rearing, especially in advance of severe winter storms, would have minimal effects on the population. © Inter-Research 2010.

Mounce H.L.,Maui Forest Bird Recovery Project | Mounce H.L.,University of Kent | Leonard D.L.,Pacific Cooperative Studies Unit | Swinnerton K.J.,Island Conservation | And 4 more authors.
Journal of Field Ornithology | Year: 2013

Maui Parrotbills (Pseudonestor xanthophrys), critically endangered Hawaiian honeycreepers endemic to the island of Maui, are restricted to a single population of ∼500 individuals located in remote, mountainous terrain. From January to June 2006-2011, we located nests and fledglings in the Hanawi Natural Area Reserve (NAR) in east Maui, Hawaii, to document nest success and annual reproductive success. Nest success is a commonly used measure of productivity and is a central component of many demographic studies. Annual reproductive success is less frequently documented because greater effort is required to monitor the reproductive success of breeding pairs through time. However, for species whose nests are difficult to locate or access, such as Maui Parrotbills, the presence or absence of fledged young may provide a more accurate measure of breeding success than monitoring nests. During our study, we located and determined the outcome of 30 nests to document nest success, and monitored 106 territories for the presence or absence of fledglings to calculate annual reproductive success. Nest success probability was 19% (N= 30) and seasonal nest success was 46%. During our monitoring efforts, 49 of 106 breeding pairs produced a single fledged young. Because parrotbills typically have single egg clutches and only re-nest after nests fail, the presence or absence of a fledgling is an indication of a pair's overall reproductive success for a breeding season. Based on the number of fledglings per pair, our estimate of annual reproductive success was 46%, confirming our initial productivity estimate from nests. Thus, our results indicate that the two methods, determining annual reproductive success by monitoring fledglings and calculating nest success, provide similar estimates of annual productivity for Maui Parrotbills. Based on our estimates, the parrotbill population appears to be demographically stable. However, our productivity estimate was based only on the population at Hanawi, an area representing just 3% of the total range of parrotbills. Thus, our results may not accurately reflect the status of parrotbills over their entire range. © 2013 The Authors. Journal of Field Ornithology © 2013 Association of Field Ornithologists.

Warren C.C.,Maui Forest Bird Recovery Project | Motyka P.J.,Northern Arizona University | Mounce H.L.,Maui Forest Bird Recovery Project
Journal of Field Ornithology | Year: 2015

Prior to the reintroduction of a species, managers need an understanding of the expected behavior of the species in the new habitat. How a species uses its habitat and how much space individuals require are particularly important when conservation lands are limited. Critically endangered Maui Parrotbills (Kiwikiu, Pseudonestor xanthophrys) once occupied a variety of habitats on the Hawaiian islands of Maui and Moloka'i, but, due to habitat loss and disease, are now restricted to a fraction of their former range. To prevent their extinction, reintroducing parrotbills to historically occupied native, mesic forest on the leeward slopes of Haleakalā is considered a critical recovery action. Managers have selected Nakula Natural Area Reserve (NAR) as the site of translocation and restoration efforts are currently underway to support this goal. In addition, other species, including endemic Maui 'Alauahio (Maui Creeper, Paroreomyza montana), may recolonize these forests naturally as the habitat improves. However, estimates of the home range sizes of focal species are needed so that managers can estimate how many individuals might be able to occupy new habitats. Our objective therefore was to estimate the home range sizes of parrotbills and 'alauahio at three sites within their current ranges to provide estimates of typical habitat and space use patterns. Using resightings of color-banded birds from 2007 to 2014, we calculated home ranges using minimum convex polygons and kernel density estimators. Depending on estimation technique, parrotbill home ranges were estimated to encompass 9.29 ± 1.29 (SE) ha or 9.63 ± 1.51 ha, and pairs occupied ranges of 11.8 ha or 14.5 ha. 'Alauahio home ranges were 0.85 ± 0.09 ha or 0.87 ± 0.08 ha in size. Home range sizes varied among study sites for both species, likely reflecting the influence of local habitat attributes and quality on movement patterns and space use. Although we do not know how these species will behave in the new habitat, our estimates of home range size provide guidance for managers planning the reintroduction of parrotbills to Nakula NAR. © 2015 Association of Field Ornithologists.

Mounce H.L.,Maui Forest Bird Recovery Project | Mounce H.L.,University of Kent | Iknayan K.J.,University of California at Berkeley | Leonard D.L.,U.S. Fish and Wildlife Service | And 2 more authors.
Bird Conservation International | Year: 2014

The accurate estimation of key demographic parameters is invaluable for making decisions about the management of endangered wildlife but such estimates are often difficult to obtain. Parameters such as species-specific apparent survival rates are an important component in understanding population ecology and informing management decisions. The Maui Parrotbill Pseudonestor xanthophrys is a 'Critically Endangered' Hawaiian honeycreeper endemic to the Island of Maui. We used an 18-year encounter history dataset comprising 146 marked individuals to estimate apparent survival between sexes and age classes (juvenile, adult). A difference in survival rates between sexes was strongly supported; 0.72 ± 0.04 for adult females and 0.82 ± 0.03 for adult males. This difference may be a reflection of either reproductive costs or additional risks of incubation and brooding, such as depredation. We also found support for age-biased survival, but limited information for juveniles did not provide a well-supported model fit for our data (juvenile survival = 0.17 ± 0.15; adults = 0.78 ± 0.02). However, apparent adult survival was similar to that of other Hawaiian passerines (mean 0.78 ± 0.03, n = 16). These results suggest that efforts to prevent the extinction of this species may benefit from future management strategies focused on increasing female survival such as predator reduction. Copyright © BirdLife International 2013A.

Warren C.C.,Maui Forest Bird Recovery Project | Veech J.A.,Texas State University | Weckerly F.W.,Texas State University | O'Donnell L.,Austin Austin Water Utility | Ott J.R.,Texas State University
Auk | Year: 2013

Abstract.-Abundance estimators that account for imperfect detection, such as N-mixture models, assume that detection of individuals is independent of abundance. Using spot-mapping and N-mixture models applied to point-count data, we estimated abundance of Goldencheeked Warblers (Setophaga chrysoparia) in two years at six study sites at the Balcones Canyonlands Preserve, Austin, Texas. N-mixture model estimates deviated from spot-mapping estimates at the site level by overestimating at low abundances, and at the survey-station level by underestimating at high abundance, which suggests that model assumptions may have been violated. We tested whether detection of individuals is influenced by abundance by assessing per capita song rate in relation to abundance. Per capita song rate increased with abundance, illustrating how the behavior of a territorial passerine may violate the independent-detectability assumption. We next explored violation of this assumption at the survey-station level by applying N-mixture models to simulated data exhibiting heterogeneity in detection. This exercise revealed a slight but increasingly negative bias (underestimation of abundance) in the estimator as the actual abundance increased, given positive density-dependent detection. The simulations also revealed a potential effect of sampling variation on misestimation by N-mixture model estimators. Assessing the strength, basis, and prevalence of density-dependent detection; further analyzing the effects of nonrandom heterogeneity in producing estimator bias; and accounting for nonrandom detection heterogeneity in abundance estimators are fruitful areas for further study.© 2013 by The American Ornithologists' Union. All rights reserved.

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