Publications

We investigated the reproductive ecology and effects of egg parasitism on the Samoan swallowtail butterfly (Papilio godeffroyi), which survives only on Tutuila Island, American Samoa, after having disappeared from the much larger islands of Upolu and Savai‘i in independent Samoa. During monthly surveys of its only known host plant, Micromelum minutum, across eight sites in 2013 and 2014...

The animal gut microbiome can have a strong influence on the health, fitness, and behavior of its hosts. The composition of the gut microbial community can be influenced by factors such as diet, environment, and evolutionary history (phylosymbiosis). However, the relative influence of these factors is unknown in most bird species. Furthermore, phylosymbiosis studies have largely focused...

This study updates the status assessment of four endemic endangered Hawaiian waterbird species—ae‘o (Hawaiian stilt, Himantopus mexicanus knudseni), ‘alae ke‘oke‘o (Hawaiian coot, Fulica alai), ‘alae ‘ula (Hawaiian gallinule, Gallinula galeata sandvicensis), and koloa maoli (Hawaiian duck, Anas wyvilliana)—from 1986 to 2016 by incorporating new data from 2017–2023. State-space models...

Caridean shrimps (Caridea) are the dominant macroinvertebrates in most anchialine ecosystems. Hawaiian anchialine ecosystems, primarily composed of shallow surface pools connected to the ocean via hypogeal networks of cracks, tubes, and other voids, support 10 caridean shrimp species, including two federally listed as endangered. Little is known about most of these species. The objective...

Dietary decisions by predators can affect prey abundance and overall food web dynamics. Many predators do not forage on the same prey at the same frequency throughout their lives. Ontogenetic shifts in prey preference are not, however, often accounted for when modeling food web relationships, despite growing literature that suggests that stage specific dietary relationships may be an...

The effective management of at-risk species often requires fine-scale actions by natural resource managers. However, balancing these actions with concurrent land uses is challenging, particularly when compounded by the interplay of climate shifts, and escalating wildland–urban interface conflicts. We used spatial prioritization tools designed for biodiversity conservation to help...

Gape-limited predators (e.g., snakes, many fish) are not generally expected to pose a predation threat to prey that are too large for them to swallow. However, the extent to which snakes predate on prey that exceed their gape limitation remains largely unknown. We conducted the first study to investigate the influence of both prey and predator sizes on the frequency of ingestion success...

Nihoa and Laysan Island, part of the Northwestern Hawaiian Islands, are host to three endangered passerine species—Nihoa finch (Telespiza ultima), Nihoa millerbird (Acrocephalus familiaris kingi), and Laysan finch (Telespiza cantans). Using point-transect distance sampling survey records from 2010 to 2022 for Nihoa and 2013 to 2019 for Laysan Island, we estimated the density and...

There is broad concern that the range shifts of global flora and fauna will not keep up with climate change, increasing the likelihood of population declines and extinctions. Many populations of nonnative species already have advantages over native species, including widespread human-aided dispersal and release from natural enemies. But do nonnative species also have an advantage with...

Federal, state, and non-governmental partners resurveyed landbirds in the Kaʻū Rainforest on the Island of Hawai‘i in 2019. Point-transect distance sampling was conducted in Hawaiʻi Volcanoes National Park, Kaʻū Forest Reserve, Kapāpala Forest Reserve, and Kapāpala Cooperative Game Management Area. This is the first comprehensive survey of the region since 2008. Through a collaborative...

The yǻyaguak (Mariana swiftlet, Aerodramus bartschi) is an endangered cave-roosting species native to Guam and southern Mariana Islands, Micronesia. The population on Guam has declined substantially over the last half century, likely due to the introduction of the brown treesnake (Boiga irregularis), but other factors have been proposed including habitat loss, pesticides, reduced food...

Efforts to recover the critically endangered ko’ko’ (Guam rail, Hypotaenidia owstoni) through establishing an experimental population on the island of Rota in the Commonwealth of the Northern Mariana Islands have been ongoing for three decades. The U.S. Geological Survey collaborated with the Guam Division of Aquatic and Wildlife Resources and the Government of Guam to evaluate whether...