Specialty: Avian ecology and conservation, demographic modeling, conservation genetics
Research Interests: My research focuses on understanding factors that affect population dynamics – why populations increase or decline over time – and through an understanding of the “why” populations change in size provide natural resource managers information on “how” to maintain healthy populations. My research has focused mainly on birds, mostly endangered species, using field research, modeling, and genetic research to understand population dynamics and identify possible conservation actions to help imperiled populations. My work in Hawai‘i is focused on the native Hawaiian forest birds.
Personal Interests: Hunting, fishing, and lounging at the beach
Education and Certifications
Ph.D. 2008 Biology, Northern Arizona University, Flagstaff, AZ
M.S. 2000 Biology, Northern Arizona University, Flagstaff, AZ
B.S. 1991 Evergreen State College, Olympia, WA
Science and Products
Mariana Swiftlet Population Analysis
Movement Patterns of the Endangered Hawaiian Hawk
Avian Malaria Genomic Research Project
Ecology and Demography of Hawaiian Forest Birds
Thresholds to Restoration
Ecology of Hawaiian Waterbirds
Population Genetics and Emergency Management of Two Kauai Island Endangered Species
Dynamics of a Koa Looper Moth Outbreak and Response by the Native Forest Community
Vulnerability of Hawaiian Forest Birds to Climate Change
Hawaii Island forest bird movement data from 2014 to 2019
Hawaii Island forest bird phenology and morphometrics from 1994 to 2019
Guam automated radio telemetry network test data 2021
Hawaii Island bird activity from 2014 through 2019
Hawai'i Island locations of 'Apapane and 'I'iwi from automated radio telemetry tracking system 2014 to 2016
Hawaii Island bird response to koa moth outbreak, 2013-2014
Hawaii Island locations of reintroduced Alala from automated radio telemetry tracking system, 2017 cohort
Avian diet and vegetation data for Hakalau Forest, Hawaii, 2012-2016
Hawaii Volcanoes National Park stable isotope values from Hawaii forest birds 2012
Hawaii Island forest bird response to simulated nest predator 2015-2016
Suppression of invasive Brown Treesnakes and reintroduction of native avifauna on Guam
Molt patterns, aging criteria, and molt-breeding seasonality of 8 native forest birds from the Island of Hawaiʻi
Distribution and trends of endemic Hawaiian waterbirds
Predation thresholds for reintroduction of native avifauna following suppression of invasive brown treesnakes on Guam
Trophic interactions and feedbacks maintain intact and degraded states of Hawaiian tropical forests
Minimizing extinction risk in the face of uncertainty: Developing conservation strategies for 2 rapidly declining forest bird species on Kaua‘i Island
Hawaiian forest bird conservation strategies for minimizing the risk of extinction: biological and biocultural considerations
Hypotheses and lessons from a native moth outbreak in a low-diversity, tropical rainforest
Optimizing trilateration estimates for tracking fine-scale movement of wildlife using automated radio telemetry networks
Activity patterns of Hawaiian forest birds in a fragmented and continuous landscape
Foraging behavior in a generalist snake (brown treesnake, Boiga irregularis) with implications for avian reintroduction and recovery
Distilling professional opinion to gauge vulnerability of Guam avifauna to Brown Treesnake predation
Science and Products
- Science
Mariana Swiftlet Population Analysis
Population counts of Mariana swiftlets is critical to understand if control of brown tree snakes in Guam have aided swiftlet recovery. USGS scientists and The University of Hawai’i at Hilo are testing videographic methods to count Mariana swiftlet population size and observe their nesting and roosting behavior.Movement Patterns of the Endangered Hawaiian Hawk
To document movement patterns and habitat use of Hawiian Hawks, GPS tags were attached to 17 individuals to track their movement across continuous, fragmented, and urban landscapes. We are now gathering multi-year tracking data to assess key aspects of habitat needs, and how these birds navigate through different ecosystems.Avian Malaria Genomic Research Project
Many factors including habitat destruction, invasive plants, non-native predators and competitors, and introduced diseases have decimated the diverse, endemic native forest bird community of Hawai‘i. In particular, avian malaria (Plasmodium relictum), which is transmitted by the introduced Southern House Mosquito (Culex quinquefasciatus), has caused dramatic declines and extinctions in many native...Ecology and Demography of Hawaiian Forest Birds
Many of Hawai‘i’s forest birds have shown significant declines in the past 200 years, with many currently listed as endangered species. Multiple threats have been identified as contributing to declines, including disease, invasive species, habitat loss, and decreased survivorship and productivity caused by introduced predators. Demographic and ecological studies are needed to determine how...Thresholds to Restoration
Mesic forests of Hawai‘i island provide an ideal system for the study of forest restoration because they have a similar history to other tropical and subtropical forests globally, while maintaining a relatively simple species assemblage. Many of these forests were cleared for grazing, and then later abandoned, to become dominated by pasture grasses that form competitive layers such that native...Ecology of Hawaiian Waterbirds
Loss of wetlands, invasive plants, and non-native predators pushed Hawaii’s waterbirds to the brink of extinction by the early 1900s, although population numbers have improved somewhat in recent decades with conservation efforts. Nonetheless, all Hawaiian waterbirds have global population sizes estimated around or below below 2,000 individuals, making them still highly vulnerable to extinction...Population Genetics and Emergency Management of Two Kauai Island Endangered Species
The Challenge: The Akeke’e (Loxops caeruleirostris) and the Akikiki (Oreomystis bairdi), two species of Hawaiian honeycreeper, are critically endangered bird species endemic to high elevation ohia forests on the Hawaiian island of Kauai. Both species have suffered severe population declines and range contractions in recent decades. Akeke’e are currently thought to number ca. 950 wild individuals...Dynamics of a Koa Looper Moth Outbreak and Response by the Native Forest Community
A massive outbreak of the native koa looper moth (Scotorythra paludicola; Geometridae) defoliated more than a third of the koa (Acacia koa) forest on Hawai‘i Island during 2013–2014. Our objective was to record the dynamics of the koa looper (Scotorythra paludicola) outbreak and evaluate the response to the outbreak by the forest ecosystem generally as well as select native and invasive species...Vulnerability of Hawaiian Forest Birds to Climate Change
The Hawaiian Islands are home to some of the world’s most culturally valuable but imperiled forest birds, including brightly colored native honeycreepers, many of which are threatened or endangered. One of the major threats these birds face is avian malaria, which is spread by a species of introduced mosquito and can have death rates exceeding 90 percent. For decades, upper mountain forests have p... - Data
Hawaii Island forest bird movement data from 2014 to 2019
This data release includes data and metadata containing estimated and predicted locations of radio telemetered Hawaiian forest birds. Radio telemetry data was collected using an automated radio telemetry network from 2014 to 2019 from birds in two study sites, one a continuous forest and the other a fragmented forest. Four bird species that varied in age and sex were studied: the nectarivorous ʻiʻHawaii Island forest bird phenology and morphometrics from 1994 to 2019
We examined data from multiple studies (1994-2020) conducted across the avian annual cycle, from multiple locations, to evaluate molt patterns and establish criteria for assignment of age and sex based on the WRP (Wolfe-Ryder-Pyle) method, or molt-cycle age classification system designed specifically for tropical species. In addition, we describe the phenologies of molt and breeding and quantify tGuam automated radio telemetry network test data 2021
A major advancement in the use of radio telemetry has been the development of automated radio tracking systems (ARTS) which allow animal movements to be tracked continuously. A new ARTS approach is the use of a network of simple radio receivers (nodes) that collect radio signal strength (RSS) values from animal-borne radio transmitters. However, the use of RSS-based localization methods in wildlifHawaii Island bird activity from 2014 through 2019
We used an automated radio telemetry network to document the activity of radio telemetered Hawaiian forest birds in two study sites, one a continuous forest and the other a fragmented forest. Four bird species were studied: the nectarivorous 'i'iwi (Drepanis coccinea) and 'apapane (Himatione sanguinea), the frugivorous 'oma'o (Myadestes obscurus), and the generalist Hawai'i 'amakihi (ChlorodrepaniHawai'i Island locations of 'Apapane and 'I'iwi from automated radio telemetry tracking system 2014 to 2016
We used an automated radio telemetry network to track the movement of two nectivorous Hawaiian honeycreepers, the 'Apapane (Himatione sanguinea) and 'I'iwi (Drepanis coccinea), collecting high temporal and spatial resolution data across the annual cycle. We identify movement syndromes using a multivariate analysis of multiple movement metrics and assessed seasonal changes in movement behavior. BiHawaii Island bird response to koa moth outbreak, 2013-2014
This data release includes metadata and tabular data that document the responses of birds to changes in habitat conditions before and after koa (Acacia koa) defoliation by koa moths (Scotorythra paludicola). Data sets document changes in the (1) use of tree species, (2) arthropod composition of diets, and (3) body mass.Hawaii Island locations of reintroduced Alala from automated radio telemetry tracking system, 2017 cohort
Alala, or Hawaiian Crow (Corvus hawaiiensis), were extinct in the wild since the early 2000s. The first effort to reintroduce captive bred Alala back into the wild was conducted at Puu Makaala Natural Area Reserve on Hawaii Island. The 2017 release cohort were released in two stages and were the only Alala in the wild. Using automated radio telemetry tracking towers (n=4) that were distributed aroAvian diet and vegetation data for Hakalau Forest, Hawaii, 2012-2016
This data release includes data and metadata on 1) avian diet 2) seed rain 3) understory plant composition 4) seedling abundance and 5) sampling locations for these sites. In addition it includes data on seedling abundance, grass cover and light levels for a grass removal/seed addition experiment . All sites were within Hakalau Forest National Wildlife Refuge on Hawaii Island. This study looked atHawaii Volcanoes National Park stable isotope values from Hawaii forest birds 2012
Blood and feathers were collected from Hawaii forest birds (Apapane and Hawaii Amakihi) in high elevation forest to assess evidence for altitudinal movement. Feathers, red blood cells and plasma were analyzed for hydrogen, carbon, and nitrogen stable isotope ratios, and these were used to infer changes in elevation and diet over time. For each species, at one of 3 sites, isotope values from one orHawaii Island forest bird response to simulated nest predator 2015-2016
Hawaii forest birds nesting in Hakalau Forest National Wildlife Refuge were exposed to models of predators near their nests to measure behavioral responses. Responses to potential nest predators included vocalization rate, movement behavior, and nestling feeding. Predators were inert stick, introduced but abundant predator, a rat, and a novel predator, a snake, that does not occur on Hawaii. - Multimedia
- Publications
Filter Total Items: 81
Suppression of invasive Brown Treesnakes and reintroduction of native avifauna on Guam
Many agencies and interest groups are committed to re-establishing components of Guam's native avifauna through the reintroduction of captive-reared birds or translocation from other islands in the Marianas if the Brown Treesnake (Boiga irregularis; BTS) can be eliminated. Island-wide eradication of BTS from Guam continues to appear out of reach, but with recent and future advancement in BTS supprMolt patterns, aging criteria, and molt-breeding seasonality of 8 native forest birds from the Island of Hawaiʻi
Much of our knowledge on the patterns and timing of breeding and molting come from studies of temperate region birds, yet tropical birds can have markedly different phenologies. The Hawaiian Islands support multiple endemic bird species that have evolved for millions of years in isolation to a tropical environment with minimal seasonality. We examined data from multiple studies (1994–2020) conductDistribution and trends of endemic Hawaiian waterbirds
Four endemic species of wetland-dependent waterbirds occur on the main Hawaiian Islands, all of which have experienced sharp population declines and are listed as endangered species. Twice per year, state-wide surveys are conducted to count waterbirds, but these surveys are evaluated only infrequently. We used a state-space approach to evaluate long-term (1986–2016) and short-term (2006–2016) trenPredation thresholds for reintroduction of native avifauna following suppression of invasive brown treesnakes on Guam
The brown treesnake (BTS) (Boiga irregularis) invasion on Guåhan (in English, Guam) led to the extirpation of nearly all native forest birds. In recent years, methods have been developed to reduce BTS abundance on a landscape scale. To help assess the prospects for the successful reintroduction of native birds to Guåhan following BTS suppression, we modeled bird population persistence based on theTrophic interactions and feedbacks maintain intact and degraded states of Hawaiian tropical forests
Feedbacks within ecosystems can lead to internal reinforcement of the current state providing ecosystem resilience. Often, multiple biotic interactions across trophic levels play a role in such feedbacks, yet these are generally studied independently, obscuring the relative importance of interactions among different factors. We look at various potential feedbacks in intact and degraded mesic foresMinimizing extinction risk in the face of uncertainty: Developing conservation strategies for 2 rapidly declining forest bird species on Kaua‘i Island
Many species around the world are declining precipitously as a result of multiple threats and changing climate. Managers tasked with protecting species often face difficult decisions in regard to identifying which threats should be addressed, given limited resources and uncertainty in the success of any identified management action. On Kaua‘i Island, Hawai‘i, USA, forest bird species have experienHawaiian forest bird conservation strategies for minimizing the risk of extinction: biological and biocultural considerations
The iconic forest birds of Hawai‘i are facing a conservation crisis. Across the Hawaiian Islands, native forest birds have been experiencing population declines that have accelerated in the last one to two decades. While habitat loss, invasive species, and non-native predators have negatively affected forest bird species for hundreds of years, and continue to do so, introduced diseases, particularHypotheses and lessons from a native moth outbreak in a low-diversity, tropical rainforest
Outbreaks of defoliating insects in low-diversity tropical forests occur infrequently but provide valuable insights about outbreak ecology in temperate environments and in general. We investigated an extensive outbreak of the endemic koa moth (Scotorythra paludicola), which defoliated endemic koa trees (Acacia koa) over a third of their range on Hawai‘i Island during 2013 and 2014. At Hakalau ForeOptimizing trilateration estimates for tracking fine-scale movement of wildlife using automated radio telemetry networks
A major advancement in the use of radio telemetry has been the development of automated radio tracking systems (ARTS), which allow animal movements to be tracked continuously. A new ARTS approach is the use of a network of simple radio receivers (nodes) that collect radio signal strength (RSS) values from animal-borne radio transmitters. However, the use of RSS-based localization methods in wildliActivity patterns of Hawaiian forest birds in a fragmented and continuous landscape
Activity patterns are a key component of avian life history and behavior, and decisions about how activity periods are structured can have important fitness implications. Despite the importance of activity patterns, individual variability in activity is poorly studied in small birds. We used automated radio telemetry to track Hawaiian forest birds from three dietary guilds in a continuous forest,Foraging behavior in a generalist snake (brown treesnake, Boiga irregularis) with implications for avian reintroduction and recovery
Broad foraging classifications, such as generalist or specialist forager, are generally beneficial for population management in defining expectations of typical behavior. However, better understanding as to how individual variance in behavior interfaces with management actions, such as control of an invasive predator (such as brown treesnakes; Boiga irregularis) responsible for ecological collapseDistilling professional opinion to gauge vulnerability of Guam avifauna to Brown Treesnake predation
The avifauna of Guam was devastated by the introduction of the Brown Treesnake, and the restoration of native birds would need to address the problem with eradication or suppression of BTS. With eradication of the snake unlikely in the near term, and suppression capabilities limited to specific finite areas, key information for reintroductions is how low BTS abundance will likely need to be for ea - News