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 different factors effect population health and viability, and models need to be developed to determine the relative effects of different factors.
Overview:
Hawai‘i’s forest birds are one of the most imperiled group of birds in the world. A large number of threats currently exist, and climate change threatens to bring more pressure on the species. This research combines empirical research and population modeling to provide insights into threats and help mangers develop conservation strategies to ensure persistence of these species of birds. A number of interrelated, complementary projects are underway toward this end. Field demographic and ecological studies are being conducted at key forest bird reserves and ecological models are being developed to better understand forest bird population dynamics to provide information valuable for resource managers.
Project Objectives:
Quantify and understand factors limiting populations of native Hawaiian birds, specifically how factors affect survivorship, productivity, and movement, and develop information to aid managers in conservation actions. Better understand links between habitat characteristics (quality) and population densities and viability of Hawaiian forest birds. Explore the development of disease resistance in native Hawaiian bird populations.
Highlights and Key Findings:
We have brought together multiple lines of research, studies of survival, productivity, movement, and are combining them into models that allow us to understand processes influencing population dynamics, evaluate effectiveness of conservation actions, and make predictions about the impact of future events.
At Hakalau Forest National Wildlife Refuge (NWR), on the island of Hawai‘i, we completed 5 seasons (2012–2016) of demographic research (mark and recapture and nest monitoring) for Hawai‘i forest birds. During this time more than: 3,600 birds were banded, 1,350 banded birds were recaptured, and 900 forest bird nests were found. Additionally, using a network of automated radio telemetry tracking towers around Hakalau Forest NWR we tracked long-distance movements in two species, ‘I‘iwi and Apapane, and we have linked movements with demographic findings. Using historical datasets and recent research results we have developed demographic models to understand and predict population dynamics.
Studies on the island of Kaua‘i have explored the population size and viability forest bird populations restricted to the island.
Progress:
Completed Analyses and results are detailed in peer-reviewed publications listed under the Publications tab.
Below are data or web applications associated with this project.
Hawaii Volcanoes National Park stable isotope values from Hawaii forest birds 2012
Below are publications associated with this project.
Divergent movement patterns of adult and juvenile ‘Akohekohe, an endangered Hawaiian Honeycreeper
Stable isotope analysis of multiple tissues from Hawaiian honeycreepers indicates elevational movement
Response to terrestrial nest predators among endemic and introduced Hawaiian birds
Evaluating community-level response to management actions across a diverse Hawaiian forest bird community
Seasonality and prevalence of pollen collected from Hawaiian nectarivorous birds
Research and management priorities for Hawaiian forest birds
The effect of isolation, fragmentation, and population bottlenecks on song structure of a Hawaiian honeycreeper
Rapid colonization of a Hawaiian restoration forest by a diverse avian community
Program MAMO: Models for avian management optimization-user guide
Altitudinal migration and the future of an iconic Hawaiian honeycreeper in response to climate change and management
Movements of four native Hawaiian birds across a naturally fragmented landscape
Linking occupancy surveys with habitat characteristics to estimate abundance and distribution in an endangered cryptic bird
Below are news stories associated with this project.
- Overview
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 different factors effect population health and viability, and models need to be developed to determine the relative effects of different factors.
An ‘i‘iwi in an ‘ōhi‘a tree. Photo: K. Burnett Hawai‘i akepa captured at Hakalau Forest National Wildlife Refuge, Hawai‘i Island. Photo: USGS Overview:
Hawai‘i’s forest birds are one of the most imperiled group of birds in the world. A large number of threats currently exist, and climate change threatens to bring more pressure on the species. This research combines empirical research and population modeling to provide insights into threats and help mangers develop conservation strategies to ensure persistence of these species of birds. A number of interrelated, complementary projects are underway toward this end. Field demographic and ecological studies are being conducted at key forest bird reserves and ecological models are being developed to better understand forest bird population dynamics to provide information valuable for resource managers.
Project Objectives:
Quantify and understand factors limiting populations of native Hawaiian birds, specifically how factors affect survivorship, productivity, and movement, and develop information to aid managers in conservation actions. Better understand links between habitat characteristics (quality) and population densities and viability of Hawaiian forest birds. Explore the development of disease resistance in native Hawaiian bird populations.
Highlights and Key Findings:
We have brought together multiple lines of research, studies of survival, productivity, movement, and are combining them into models that allow us to understand processes influencing population dynamics, evaluate effectiveness of conservation actions, and make predictions about the impact of future events.
Banding station set-up at Hakalau Forest National Wildlife Refuge. Photo: E. Paxton At Hakalau Forest National Wildlife Refuge (NWR), on the island of Hawai‘i, we completed 5 seasons (2012–2016) of demographic research (mark and recapture and nest monitoring) for Hawai‘i forest birds. During this time more than: 3,600 birds were banded, 1,350 banded birds were recaptured, and 900 forest bird nests were found. Additionally, using a network of automated radio telemetry tracking towers around Hakalau Forest NWR we tracked long-distance movements in two species, ‘I‘iwi and Apapane, and we have linked movements with demographic findings. Using historical datasets and recent research results we have developed demographic models to understand and predict population dynamics.
Studies on the island of Kaua‘i have explored the population size and viability forest bird populations restricted to the island.
Progress:
Completed Analyses and results are detailed in peer-reviewed publications listed under the Publications tab.
Apapane perched on a branch. Photo: R. Kohley - Data
Below are data or web applications associated with this project.
Hawaii 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 or - Publications
Below are publications associated with this project.
Filter Total Items: 22Divergent movement patterns of adult and juvenile ‘Akohekohe, an endangered Hawaiian Honeycreeper
The movement patterns of birds across a landscape are often highly variable and influenced by complex interactions between individuals and environments. Because periods of movement can be marked by high mortality, especially among juvenile birds, understanding these patterns may be vital for the conservation of many bird species. However, these patterns can be challenging to quantify. We used radiAuthorsAlex X Wang, Eben H. Paxton, Hanna L Mounce, Paulo Marcos GorresenStable isotope analysis of multiple tissues from Hawaiian honeycreepers indicates elevational movement
We have limited knowledge of the patterns, causes, and prevalence of elevational migration despite observations of seasonal movements of animals along elevational gradients in montane systems worldwide. While a third of extant Hawaiian landbird species are estimated to be elevational migrants this assumption is based primarily on early naturalist’s observations with limited empirical evidence. InAuthorsKristina L. Paxton, Jeffery F Kelly, Sandra M Pletchet, Eben H. PaxtonResponse to terrestrial nest predators among endemic and introduced Hawaiian birds
Birds free from nest predators for long periods may either lose the ability to recognize and respond to predators or retain antipredator responses if they are not too costly. How these alternate scenarios play out has rarely been investigated in an avian community whose members have different evolutionary histories. We presented models of two nest predators (rat and snake) and a negative control (AuthorsGeorge C Cummins, Tad C Theimer, Eben H. PaxtonEvaluating community-level response to management actions across a diverse Hawaiian forest bird community
Although species‐specific approaches are necessary to understand the dynamics of individual species composing a community, they do not offer a framework for making optimal management decisions at the community level. Here, we present a simple framework for comparing the response of entire communities to multiple management scenarios. Our approach uses a weighted average of standardized species‐speAuthorsAlban Guillaumet, Eben H. PaxtonSeasonality and prevalence of pollen collected from Hawaiian nectarivorous birds
Hawaiian nectarivorous forest birds play a vital ecological role as pollinators in Hawaiian ecosystems. However, little is known about what nectar resources are utilized by Hawai‘i’s nectarivorous birds, how seasonality influences nectar availability, and how nectar preference differs by bird species. We sampled pollen from the heads of ‘i‘iwi (Drepanis coccinea), ‘apapane (Himatione sanguinea), HAuthorsKathryn van Dyk, Kristina L. Paxton, Patrick J. Hart, Eben H. PaxtonResearch and management priorities for Hawaiian forest birds
Hawai‘i's forest birds face a number of conservation challenges that, if unaddressed, will likely lead to the extinction of multiple species in the coming decades. Threats include habitat loss, invasive plants, non-native predators, and introduced diseases. Climate change is predicted to increase the geographic extent and intensity of these threats, adding urgency to implementation of tractable coAuthorsEben H. Paxton, Megan Laut, John P. Vetter, Steve J. KendallThe effect of isolation, fragmentation, and population bottlenecks on song structure of a Hawaiian honeycreeper
Little is known about how important social behaviors such as song vary within and among populations for any of the endemic Hawaiian honeycreepers. Habitat loss and non‐native diseases (e.g., avian malaria) have resulted in isolation and fragmentation of Hawaiian honeycreepers within primarily high elevation forests. In this study, we examined how isolation of Hawai'i ‘amakihi (Chlorodrepanis virenAuthorsJoshua M. Pang-Ching, Kristina L. Paxton, Eben H. Paxton, Adam A. Pack, Patrick J. HartRapid colonization of a Hawaiian restoration forest by a diverse avian community
Deforestation of tropical forests has led to widespread loss and extirpation of forest bird species around the world, including the Hawaiian Islands which have experienced a dramatic loss of forests over the last 200–800 years. Given the important role birds play in forest ecosystem functions via seed dispersal and pollination, a bird community's response to forest restoration is an important measAuthorsEben H. Paxton, Stephanie G. Yelenik, Tracy E. Borneman, Eli Rose, Richard J. Camp, Steve J. KendallProgram MAMO: Models for avian management optimization-user guide
The following chapters describe the structure and code of MAMO, and walk the reader through running the different components of the program with sample data. This manual should be used alongside a computer running R, so that the reader can copy and paste code into R, observe the output, and follow along interactively. Taken together, chapters 2–4 will allow the user to replicate a simulation studAuthorsAlban Guillaumet, Eben H. PaxtonAltitudinal migration and the future of an iconic Hawaiian honeycreeper in response to climate change and management
Altitudinal movement by tropical birds to track seasonally variable resources can move them from protected areas to areas of increased vulnerability. In Hawaiʻi, historical reports suggest that many Hawaiian honeycreepers such as the ‘I‘iwi (Drepanis coccinea) once undertook seasonal migrations, but the existence of such movements today is unclear. Because Hawaiian honeycreepers are highly susceptAuthorsAlban Guillaumet, Wendy A. Kuntz, Michael D. Samuel, Eben H. PaxtonMovements of four native Hawaiian birds across a naturally fragmented landscape
Animals often increase their fitness by moving across space in response to temporal variation in habitat quality and resource availability, and as a result of intra and inter-specific interactions. The long-term persistence of populations and even whole species depends on the collective patterns of individual movements, yet animal movements have been poorly studied at the landscape level. We quantAuthorsJessie L. Knowlton, David J. Flaspohler, Eben H. Paxton, Tadashi Fukami, Christian P. Giardina, Daniel S. Gruner, Erin E. Wilson RankinLinking occupancy surveys with habitat characteristics to estimate abundance and distribution in an endangered cryptic bird
Accurate estimates of the distribution and abundance of endangered species are crucial to determine their status and plan recovery options, but such estimates are often difficult to obtain for species with low detection probabilities or that occur in inaccessible habitats. The Puaiohi (Myadestes palmeri) is a cryptic species endemic to Kauaʻi, Hawai‘i, and restricted to high elevation ravines thatAuthorsLisa H. Crampton, Kevin W. Brinck, Kyle E. Pias, Barbara A. P. Heindl, Thomas Savre, Julia S. Diegmann, Eben H. Paxton - News
Below are news stories associated with this project.