Avian Biology
Information about the biology and natural history of a species is valuable for purely academic reasons, and in many cases such information also is essential for assessing the conservation status of a species and for designing and implementing effective conservation actions. At PRC, we recognize the importance and value of basic biological research and the foundation this provides for effective conservation. We have undertaken numerous studies to advance the state of knowledge about the biology of various bird species. Many of our conservation projects have begun with gathering biological information about the target species and the threats that it faces.
Our research on avian biology can be divided into several categories:
Demography, Diseases, Genetics, Reproductive Biology, and Behavior
Demography
Information about fundamental demographic parameters like survival and reproduction are crucial to assessing conservation status and often in measuring the effectiveness of management actions. We have used long-term mark-recapture data to measure survival and other demographic parameters in seabirds, including the Laysan Albatross and Christmas Shearwater, and in Hawaiian forest birds, including the Oahu Elepaio, Puaiohi, and Kiwikiu or Maui Parrotbill.
In the Oahu Elepaio, measures of survival and reproduction were important in determining that nest predation by non-native rats was the most serious threat to the species, and they have continued to be useful in measuring the effectiveness of rat control methods.
In the Laysan Albatross, measuring survival and recruitment is complex and difficult because of the delayed maturation in this species and because adults sometimes skip breeding in some years. The colony at Kaena Point, Oahu, has provided an ideal system in which to investigate the demography of this iconic species.
Long-term studies of the Hawaii Elepaio by Eric VanderWerf at Hakalau Forest National Wildlife Refuge provided some of the most detailed demographic information about any species of Hawaiian forest bird.
To download PDF copies of publications and reports about our research projects that have involved avian demography, click on the numbered link next to the titles below. All our publications are listed chronologically on our publications page[EV4] .
108 Habitat Use and Status of the Bokikokiko or Christmas Island Warbler (Acrocephalus aequinoctialis).
106 Juvenile survival, recruitment, population size, and effects of avian pox virus in Laysan Albatross (Phoebastria immutabilis) on Oahu, Hawaii, USA
102 Status and demographic rates of the Christmas Shearwater on Kure Atoll.
100 Survival estimates of wild and captive-released Puaiohi, an endangered Hawaiian thrush.
78 Survival Estimates for Two Hawaiian Honeycreepers.
75 Estimating survival and life stage transitions in the Laysan Albatross using multi-state mark-recapture models.
64 Demography and Natural History of Laysan Albatross on Oahu, Hawaii.
63 Importance of nest predation by alien rodents and avian poxvirus in conservation of Oahu elepaio.
60 Sources of variation in survival, recruitment, and natal dispersal of the Hawai’i ‘Elepaio.
32 Demography of Hawai`i `Elepaio: variation with habitat disturbance and population density.
22 Effects of alien rodent control on demography of the O`ahu `Elepaio, an endangered Hawaiian forest bird.
Diseases
Diseases are one of the most serious threats to many bird species, especially in Hawaii, where introduced pathogens and their vectors have caused the decline and extinction of many species. We have monitored avian pox virus and its effect on the Oahu Elepaio and the Laysan Albatross for more than 20 years, and these studies have provided some of the only quantitative data on the effects of this, or any, disease on populations of wild birds.
In the Oahu Elepaio, pox virus was prevalent and caused substantial mortality in the past, but long-term monitoring revealed that pox prevalence has declined over time, indicating that elepaio have evolved resistance to this disease, facilitated to some degree by management.
In the Laysan Albatross, pox infection did not affect fledging success of chicks, but long-term monitoring of returning adults revealed that serious pox infections, while not usually fatal initially, resulted in lower survival probability later in life, and decreased chance of attracting a mate.
To download PDF copies of publications and reports about our projects that have involved avian diseases, click on the numbered link next to the titles below. All our publications are listed chronologically on our publications page.
151 Improved status of the conservation-reliant Oahu Elepaio through effective management and natural adaptation.
106 Juvenile survival, recruitment, population size, and effects of avian pox virus in Laysan Albatross (Phoebastria immutabilis) on Oahu, Hawaii, USA.
56 Prevalence of avian pox virus and effect on the fledging success of Laysan Albatross
41 Distribution and prevalence of mosquito-borne diseases in O`ahu `Elepaio
14 Distribution and potential impacts of avian poxlike lesions in ‘Elepaio at Hakalau Forest National Wildlife Refuge
Genetics
We have worked with mitochondrial DNA, microsatellites, and nuclear markers to examine the population genetics of Laysan and Black-footed Albatrosses. We examined variation in mitochondrial DNA among Elepaio on Kauai, Oahu, and Hawaii, which, along with behavioral and ecological evidence, resulted in each being recognized as a distinct species endemic to a single island.
To download PDF copies of publications and reports about our projects that have involved genetics, click on the numbered link next to the titles below. All our publications are listed chronologically on our publications page[EV6] .
92 Population genetic structure among highly remote breeding colonies of the Black-footed albatross, Phoebastria nigripes, in North Pacific.
69 Inferring colonization history and dispersal patterns of a long lived seabird by combining genetic and empirical data.
65 Stepping stone speciation in Hawaii’s flycatchers: Molecular divergence supports new island endemics within the elepaio
Reproductive Biology
Measuring reproduction and that factors that influence it is fundamental to understanding a species, and doing so often provides useful information about methods for improving its status. At PRC we have several long-term projects to collect data on reproduction of native bird species.
We have been monitoring reproduction of the Oahu Elepaio for almost 30 years, and this long-term data set has been valuable for examining patterns in reproductive behavior and effects of environmental variation on breeding biology.
Our long-term study of the Laysan Albatross at Kaena Point has provided an ideal system in which to examine patterns in reproductive biology of the species, and has allowed us to measure some demographic patterns in this species for the first time, including juvenile survival and age-specific recruitment probability.
We began monitoring breeding of White Terns in urban Honolulu 20 years ago, which showed that it is thriving and that breeding success is the highest recorded anywhere in the world for this species, despite the abundance of predators and the many anthropogenic sources of distrurbance.
137 Factors affecting breeding success of White Terns (Gygis alba; Aves: Laridae) in urban environments of Honolulu, Hawai’i.
132 Breeding season shift by the Oahu Elepaio (Chasiempis ibidis) in response to changing rainfall patterns.
101 Adaptive value of same sex pairing in Laysan Albatross.
96 Breeding performance of Laysan Albatrosses (Phoebastria immutabilis) in a foster parent program.
95 Breeding biology of Red-Tailed Tropicbirds Phaethon rubricauda and response to predator control on O’ahu, Hawai’i
82 Evolution of nesting height in an endangered Hawaiian forest bird in response to a non-native predator.
70 Red-footed Booby Sula sula breeding success at Ulupa’u Crater, Marine Corps Base Hawaii.
Animal Behavior
Animal Behavior is a fascinating topic that is interesting for academic reasons, and an understanding foraging and other behaviors also can be important for understanding the nature of threats and how to mitigate them. At PRC we have undertaken several behavioral research projects, and also opportunistically documented some unusual behaviors in birds.
139 Laysan albatrosses exhibit complex behavioral plasticity in the subtropical and subarctic North Pacific Ocean.
129 Underwater behavior of Christmas Shearwaters Puffinus nativitatis from Kure Atoll.
113 Albatross-borne loggers show feeding on deep-sea squids: implications for the study of squid distributions.
109 Data loggers in artificial eggs reveal that egg-turning behavior varies on multiple ecological scales in seabirds.
67 Bringing home the trash: do colony-based differences in foraging lead to increased plastic ingestion in Laysan Albatrosses?
55 Foraging and Nesting of the `Akikiki or Kaua`i Creeper (Oreomystis bairdi).
52 Biogeography of `Elepaio: evidence from inter-island song playbacks.
37 Elepaio “anting” with a garlic snail and a Schinus fruit.
11 Breeding biology and territoriality of the Hawaii Creeper.
6 Intraspecific variation in ‘Elepaio foraging behavior in Hawaiian forests of different structures.
4 Scales of habitat selection by foraging ‘Elepaio in undisturbed and human-altered Hawaiian forests.
