Hawaii Wildlife Ecology Lab

Permanent URI for this collectionhttps://hdl.handle.net/10125/66566

Browse

Recent Submissions

Now showing 1 - 20 of 44
  • Item type: Item ,
    The 'regime shift extinctions' hypothesis and mass extinction of waterbirds in Hawaiʻi
    (2025-09-26)
    Studies of biodiversity loss commonly imply that species extinctions occurred as a direct result of initial human settlement and thus are attributable to stewardship failures of Indigenous Peoples. However, recent studies have suggested this assumption is not supported by the evidence, prompting a global re-evaluation of existing assumptions. To assess the relationship between human arrival in the Hawaiian Islands and documented declines in waterbird biodiversity, we reviewed empirical evidence from palaeoecological studies. We first identified the time period that extinct Hawaiian waterbird species were last observed within the fossil record. We then evaluated four hypotheses proposed to explain drivers of post-settlement Holocene waterbird extinctions: (1) the overkill hypothesis; (2) the deforestation hypothesis; (3) the climate change hypothesis; (4) the species introductions hypothesis. Of the 18 extinct waterbird species evaluated in this study, ten were last observed in the fossil record prior to Polynesian arrival, six were last observed in the fossil record during the Polynesian era, and two were last visually observed after European arrival. Extinctions that possibly occurred during the Polynesian era were likely caused by a suite of factors, some anthropogenic and some non-anthropogenic. Our findings contradict previous studies that attributed post-settlement Holocene waterbird extinctions to hunting and deforestation by Native Hawaiians and suggest a future line of inquiry regarding a proposed “'Regime Shift Extinctions Hypothesis” to explain complex impacts of human-mediated and climatic drivers of extinction in the Anthropocene.
  • Item type: Item ,
    Human-Wildlife Interactions of Hawaiian Waterbirds in Managed Wetlands
    (2025-05-15) Koa Grabar; Melissa R. Price; Kawika B. Winter
    At-risk Hawaiian waterbirds utilize a variety of wetland habitats, including lo‘i kalo (Indigenous wetland agro-ecosystems used to grow Colocasia esculenta, a staple Hawaiian crop); however, how these systems support species recovery remains understudied. This represents a significant knowledge gap, as the expansion of Hawaiian agro-ecosystems has the potential to provide numerous ecosystem services that benefit both local and Indigenous communities, as well as the environment, while simultaneously supporting the recovery endangered waterbirds in the face of threats such as sea level rise. These benefits include local food production and, in turn, improved food security, cultural (re)connection, and the creation of habitat for endemic and endangered wildlife. Despite these benefits, the management actions necessary to maintain a lo‘i may be perceived as disruptive or harmful to the waterbird species inhabiting them. Actions such as the clearing of vegetation, fluctuations in water levels, and presence during nesting periods, could impact nesting success, so policies that restrict these actions during the nesting season are sometimes imposed on farmers. This study aims to lay a foundation for better understanding the relationships between stewards and the Aeʻo (Hawaiian Stilt, Himantopus mexicanus knudseni), ʻAlae ʻula (Hawaiian Gallinule, Gallinula galeata sandvicensis), ʻAlae keʻokeʻo (Hawaiian Coot, Fulica alai) and pure/hybrid Koloa maoli (Hawaiian duck, Anas wyvilliana). To address this question, I will conduct surveys, inquiring about management and the steward’s thoughts regarding waterbirds at their site, and measure the alert response and flight-initiation distances of waterbirds within their respective wetlands when approached by stewards. To further elucidate these interactions, I will replicate this study at multiple types of sites where waterbirds interact with land stewards, such as state and county parks, and government-managed wetlands. I expect to find that steward perceptions and desired level of interactions, frequency of caretaking, and waterbird species type will be correlated with alert and flight initiation distances when birds are approached by stewards, compared to non- stewards. The findings of this study will help to elucidate the responses of different waterbird species and underscore the contributions of managed wetlands to waterbird recovery.
  • Item type: Item ,
    Characterization of the birdscape of a collaboratively managed Indigenous and Community Conserved Area in Hawai‘i: What is the potential for increasing native bird biodiversity?
    (2025-05-07) Eryn Opie
    Indigenous resource management practices increase habitat heterogeneity, and thus may contribute to species biodiversity while simultaneously achieving other social-ecological goals such as food production, but few if any studies to date have evaluated effects on avian biodiversity. Small patches of restored habitat may be of particular importance on islands where species historically had smaller ranges due to land area constraints. Due to factors introduced in the last few centuries, in the Hawaiian Islands lowland habitats are largely devoid of native passerines due to disease, mammalian predators, and habitat loss. In addition, native seabirds, waterbirds, and shorebirds occur in relatively small patches of suitable habitat due to impacts from invasive predators and the historical clearing of native vegetation for plantation agriculture and urban development. Given the lack of native birds in heavily human-modified areas of the Hawaiian Islands, there is a need to assess the occurrence of native birds in these landscapes, and the potential for improving native bird biodiversity with Indigenous Resource Management (IRM) practices. We utilized monthly point counts over two years to characterize the avian communities at sites within the He‘eia National Estuarine Research Reserve on the island of O‘ahu, Hawai‘i, where stewards engage in restoration of biocultural conservation practices and relationships. Our study found a higher abundance of native and endangered waterbirds and shorebirds in areas where biocultural restoration had been initiated, and few if any native birds in unrestored areas. Very few native seabirds and no native forest birds were detected indicating that additional targeted actions such as disease control, removal of invasive predators, and restoration of preferred habitat may be necessary to enable recolonization by these. Our results are consistent with other studies suggesting that even small patches of heterogenous landscapes managed under IRM practices are important contributions toward improving native bird biodiversity.
  • Item type: Item ,
    Prey selection in precocial chicks of the Endangered Hawaiian Stilt (ae‘o - Himantopus mexicanus knudseni)
    (2020-09-30) Melissa R. Price; Andreanna Cole; Kristen Harmon; Clarine Phipps
    Recovery of endangered species is dependent upon maximizing reproductive success and 1 minimizing mortality, but management actions aimed at increasing recruitment are often 2 hindered by a lack of knowledge at critical life history stages. For example, the dietary 3 preferences of precocial chicks may differ from nesting adults; thus, the optimal foraging habitat 4 may also differ between these life stages. The Endangered Hawaiian Stilt (ae‘o - Himantopus 5 mexicanus knudseni), a subspecies of the Black-necked Stilt, is considered a generalist forager, 6 but little is known regarding prey selection in precocial chicks. In this study, stable isotope 7 mixing models were used to estimate the contribution of potential prey sources to stilt chick diets 8 in wetlands on O‘ahu Island, Hawai‘i. We found predicted contributions to be similar among 9 potential prey items at a site with high prey diversity and the oldest and largest chicks. At three 10 other sites, younger chicks appeared to select particular items from among available prey, 11 including species in the orders Hemiptera (true bugs) and Araneae (spiders). Species in these 12 orders were lower in biomass compared to other species available at each site, suggesting the 13 chicks were selecting for these items from among available prey items, similar to other related 14 species. Our results suggest that Hawaiian Stilt chicks may preferentially select certain prey 15 items which are easy to handle and high in nutrients important to development, and likely 16 diversify their diet as they gain dexterity and height. The results from this study may inform 17 decisions for optimal habitat and macroinvertebrate management in Hawaiian Stilt nesting sites 18 to maximize reproductive success and survival.
  • Item type: Item ,
    Environmental drivers of seasonal shifts in abundance of wild pigs (Sus scrofa) in a tropical island environment
    (2022-09-05) Derek R. Risch; Shaya Honarvar; Melissa R. Price; Derek R. Risch
    Background: Non-native wild pigs (Sus scrofa) threaten sensitive flora and fauna, cost billions of dollars in economic damage, and pose a significant human–wildlife conflict risk. Despite growing interest in wild pig research, basic life history information is often lacking throughout their introduced range and particularly in tropical environments. Similar to other large terrestrial mammals, pigs possess the ability to shift their range based on local climatic conditions or resource availability, further complicating management decisions. The objectives of this study were to (i) model the distribution and abundance of wild pigs across two seasons within a single calendar year; (ii) determine the most important environmental variables driving changes in pig distribution and abundance; and (iii) highlight key differences between seasonal models and their potential management implications. These study objectives were achieved using zero-inflated models constructed from abundance data obtained from extensive field surveys and remotely sensed environmental variables. Results: Our models demonstrate a considerable change in distribution and abundance of wild pigs throughout a single calendar year. Rainfall and vegetation height were among the most influential variables for pig distribution during the spring, and distance to adjacent forest and vegetation density were among the most significant for the fall. Further, our seasonal models show that areas of high conservation value may be more vulnerable to threats from wild pigs at certain times throughout the year, which was not captured by more traditional modeling approaches using aggregated data. Conclusions: Our results suggest that (i) wild pigs can considerably shift their range throughout the calendar year, even in tropical environments; (ii) pigs prefer dense forested areas in the presence of either hunting pressure or an abundance of frugivorous plants, but may shift to adjacent areas in the absence of either of these conditions; and (iii) seasonal models provide valuable biological information that would otherwise be missed by common modeling approaches that use aggregated data over many years. These findings highlight the importance of considering biologically relevant time scales that provide key information to better inform management strategies, particularly for species whose ranges incl
  • Item type: Item ,
    A comparison of abundance and distribution model outputs using camera traps and sign surveys for feral pigs
    (2020-10-14) Derek R. Risch; Jeremy Ringma; Shaya Honarvar; Melissa R. Price; Derek Risch
    Species distribution models play a central role in informing wildlife management. For models to be useful, they must be based on data that best represent the presence or abundance of the species. Data used as inputs in the development of these models can be obtained through numerous methods, each subject to different biases and limitations but, to date, few studies have examined whether these biases result in different predictive spatial models, potentially influencing conservation decisions. In this study, we compare distribution model predictions of feral pig (Sus scrofa) relative abundance using the two most common monitoring methods: detections from camera traps and visual surveys of pig sign. These data were collected during the same period using standardised methods at survey sites generated using a random stratified sampling design. We found that although site-level observed sign data were only loosely correlated with observed camera detections (R2 ¼ 0.32–0.45), predicted sign and camera counts from zero-inflated models were well correlated (R2 ¼ 0.78–0.88). In this study we show one example in which fitting two different forms of abundance data using environmental covariates explains most of the variance between datasets. We conclude that, as long as outputs are produced through appropriate modelling techniques, these two common methods of obtaining abundance data may be used interchangeably to produce comparable distribution maps for decision-making purposes. However, for monitoring purposes, sign and camera trap data may not be used interchangeably at the site level.
  • Item type: Item ,
    Population size, distribution and habitat use of the Hawaiian Short-eared Owl (Asio flammeus sandwichensis) on O'ahu
    (2018-01-31) Javier Cotin; Melissa R. Price
    The Pueo (Asio flammeus sandwichensis), once common across the Hawaiian Islands, is currently state-listed as Endangered on O'ahu. The Pueo provides important ecosystem services by controlling population sizes of introduced rodents and preying on other introduced and native species, including birds and invertebrates. As the only native raptor that breeds on the main Hawaiian Islands, the Pueo plays an important role in top-down ecological regulation and is also valued by native Hawaiians and other Hawai'i residents. Although the Pueo has been recorded in a variety of vegetation types in the Hawaiian archipelago, key habitat selection variables are still unknown. In this study, we optimized a survey methodology to improve population estimates and define vegetation types important to population stability and we compared distribution among vegetation types and overall population densities of Pueo with other Short-eared Owl populations across the globe. Three different approaches were used: (a) standardized surveys by trained personnel; (b) citizen science reports of Pueo sightings submitted to an online portal www.pueoproject.com; and (c) citizen science reports to eBird www.ebird.org, a publicly available, well-established, and curated international online portal for submitting bird sighting reports. We collected more than 50 Pueo sightings in one year through the Pueo project online portal, while the eBird portal collected 43 reports in three decades. Information gathered through the citizen science portal was highly valuable for obtaining phenology and breeding event observations (nests, owlet locations, display flights), however, data collected in this manner were biased due to the lack of standard distribution of the observers, which hampered their usefulness for running distribution models or other population analyses. During the standardized surveys Pueo were observed on agricultural lands, wetlands, short grasslands and open native vegetation. Pueo were detected, on average, 23 minutes before twilight. Estimated densities ranged from 0 to 3.3 Pueo per 100 ha across vegetation types, with most detections occurring in open vegetation types, such as agricultural lands, grasslands, and wetlands. Based on observed densities, the population of Pueo inhabiting O'ahu was estimated at 807 individuals, with 95% confidence intervals of 8 to 2199. Densities obtained from standardized, randomized surveys are aligned with those studies targeting known Short-eared Owl populations with a high rate of occupancy, which does not seem to be the situation on O'ahu, especially if we consider the high level of threats that this species faces in Hawai'i and the observations of declining populations that local inhabitants have reported in person or submitted to the Pueo Project portal. Densities on O'ahu are probably similar to the ones reported in non-targeted, randomized and standardized studies, where owls occupy territories with high prey availability, but leave unoccupied low-prey-density territories. Based on this information, we consider the most likely population number to be on the lower end of the estimated range of possibilities.
  • Item type: Item ,
    Breeding phenology and daily activity of the Hawaiian Short-eared Owl (Asio flammeus sandwichensis) on O'ahu
    (2018-01-31) Javier Cotin; Kyle E. Davis; Afsheen A. Siddiqi; Melissa R. Price
  • Item type: Item ,
    Breeding Ecology of Hawaiian Short-eared Owls (Asio flammeus sandwichensis)
    (2023-06-30) Melissa R Price; Olivia Wang
    Short-eared Owls (Asio flammeus) are an appropriate study species for understanding intraspecific variations in life-history traits in raptors due to their global distribution across continental and island systems at a variety of latitudes. In Hawai‘i, little is known about the ecology of Pueo (Hawaiian Short-eared Owls, A. f. sandwichensis), but populations are thought to be in decline and are state-listed as endangered on O‘ahu. While studies of other Short-eared Owl subspecies serve as a starting point for creating conservation plans for Pueo, initial research has indicated differences in diet, habitat use, and movement ecology of Pueo versus continental Short-eared Owls. Given these differences, further regional studies from Hawai‘i are necessary to ensure management actions adequately address the needs of Pueo. In Chapter 2 of this study, I investigated the breeding ecology of Pueo using a collaborative approach to combine results from targeted nest-searching at two focal study sites on O‘ahu with incidental reports of Pueo nests across the Hawaiian Islands. In Chapter 3 I used these results to draft management recommendations to minimize disturbance to breeding Pueo. At our focal study sites, I found that Pueo select sites with greater vegetation height and density than the surrounding environment for nesting, but that these same vegetation characteristics do not necessarily correlate to increased nest survival. The diet of breeding Pueo was relatively diverse and contained more bird prey when compared to that of North American and European Short-eared Owls. However, diet did not differ significantly among breeding Pueo pairs. Across both focal study sites and incidental observations, Pueo nest initiation spanned November through July, with a peak in February and March. Pueo breeding habitat ranged from non-native dry grasslands at low-elevation to high-elevation native wet forest, showing a marked increase in breeding habitat diversity compared to North American and European Short-eared Owls. Our results establish a basis for informing Pueo conservation in Hawai‘i, including recommendations towards reducing different types of nest disturbance and data to inform spatial and temporal nest buffers. State-wide management actions must account for the expanded breeding season and diversity of breeding habitat types of Pueo.
  • Item type: Item ,
    INDIGENOUS KNOWLEDGE AND FACTORS INFLUENCING DETECTABILITY OF PUEO (HAWAIIAN SHORT-EARED OWL, ASIO FLAMMEUS SANDWICHENSIS)
    (2023-05-16) Kaleiheana-a-Pōhaku Stormcrow; Melissa R. Price; Kawika B. Winter; Noelani Puniwai
    Apex predators such as raptors play important roles in ecosystem regulation. In addition to these important roles and the charismatic nature of apex predators, apex predators often have a mirrored cultural significance for Indigenous Peoples. When their symbolic and spiritual value is so great that it affects that culture’s relationship and adaptation to the environment, they are considered Cultural Keystone Species (CKS). In addition to supporting ecosystem complexity, these species support cultural complexity regarding social identity, cultural practices, and beliefs. Pueo are the only remaining native raptor that breed across the Hawaiian archipelago, and as such play key ecological and cultural roles. In this thesis research I aimed to: (1) highlight the breadth of Indigenous Knowledge of Pueo documented in Hawaiian language newspapers and (2) identify factors influencing Pueo detectability on Hawaiʻi Island. Pueo have relationships with multiple akua (elemental forces) who play vital roles in ecosystem functionality and nutrient cycling, and have relationships with 35 species across articles, indicating our kūpuna (ancestors) understood the system stability that Pueo supported, and the functionality of the pilina (relationship) that Kānaka (Native Hawaiians) have with Pueo. Results from field surveys demonstrate that Pueo utilize every available terrestrial habitat type in Hawaiʻi, but their occupancy and detection probability are constrained by elevation and temperature respectively. On Hawaiʻi island, where Pueo co-occur with ʻIo (Buteo solitarius), we observed a potential temporal shift in their behavior. Together, the results of these chapters support the notion that Pueo are a Cultural Keystone Species and a generalist apex predator with critical cultural and ecological functions.
  • Item type: Item ,
    2022 O‘ahu ʻUaʻu kani Long-term Monitoring Project
    (2023-01-04) Melissa Price; Jessica Idle
  • Item type: Item ,
  • Item type: Item ,
    USFWS_Hawaiian Waterbirds_Annual Permit Report_2022
    (2023-01-31) Melissa Price; Taylor Shimabukuro; Jaime Botet-Rodriguez
  • Item type: Item ,
    Hawaiian Waterbird Nesting Ecology
    (2021-01-31)
  • Item type: Item ,
    Successful nesting by 2 endangered Hawaiian waterbird species in a restored Indigenous wetland agroecosystem
    (2022-03-01) Kristen C. Harmon, Eryn N. P. Opie, Ali‘i Miner, Iokepa Paty-Miner, Jonathan K. Kukea-Shultz, Kawika B. Winter, and Melissa R. Price
    The Hawaiian Stilt (Himantopus mexicanus knudseni) and Hawaiian Gallinule (Gallinula galeata sandvicensis) are federally endangered waterbirds endemic to the Hawaiian Islands. Both species are conservation-reliant; their population persistence is dependent on invasive predator control and removal of invasive plants that degrade habitat. We present observations of successful nesting by one Hawaiian Stilt pair and one Hawaiian Gallinule pair at a site managed within an adaptive Indigenous agroecological framework on the island of O‘ahu, Hawai‘i. The Hawaiian Stilt nest, found in February 2019, contained 4 eggs and produced 3 hatchlings, 2 of which were banded and monitored after hatching. The Hawaiian Gallinule nest, found in February 2020, contained 6 eggs and produced 5 hatchlings. Although no individuals were banded from this nest, 2 adults and 2 hatchlings were continuously observed in the nesting area after the eggs hatched. Lo‘i kalo Hawaiian wetland agroecosystems centered around the cultivation of kalo (taro; Colocasia esculenta), have the potential to expand Hawaiian waterbird habitat beyond state and federal protected areas. We are aware of unpublished accounts of Hawaiian waterbirds nesting in commercially farmed lo‘i kalo, but until now, there have been no previously published accounts of native waterbirds breeding in lo‘i kalo managed as Indigenous agroecosystems.
  • Item type: Item ,
    First observations of Least Tern (Sternula antillarum) eggs and other breeding observations on the island of O‘ahu, Hawai‘i
    (AllenPress, 2021-08-04) Harmon, Kristen; Phipps, Clarine; VanderWerf, Eric; Chagnon, Bethany; Price, Melissa
    The Least Tern (Sternula antillarum) commonly breeds along coastal beaches and major interior rivers of North America and the Caribbean. Least Terns have been observed in Hawai‘i since the 1970s; however, few breeding attempts have been documented. Nests have been discovered on the northwestern Hawaiian island of Midway Atoll and the southeastern Hawaiian island of Hawai‘i. While nesting is thought to also occur on the islands of O‘ahu and French Frigate Shoals based on observations of juvenile Least Terns, no observations of nests had been recorded for these islands prior to this study. In this paper we describe 2 accounts of discovering Least Tern eggs in the Ki‘i Unit of the James Campbell National Wildlife Refuge on O‘ahu, as well as several observations of breeding behavior in wetlands within the Pearl Harbor region of O‘ahu.
  • Item type: Item ,
    The role of Indigenous practices in expanding waterbird habitat in the face of rising seas
    (Elsevier, 2021-04-01) Harmon, Kristen; Winter, Kawika; Kurashima, Natalie; Fletcher, Charles; Kane, Haunani; Price, Melissa
    In Hawai‘i, as is the case globally, sea level rise threatens the availability of suitable habitat for waterbirds and other coastal species. This study examines Hawaiian wetland agro-ecosystems (loʻi) as social-ecological systems that may meet human needs while expanding nesting habitat of endangered waterbirds, if restored under an Indigenous Resource Management paradigm. We applied spatial analysis to project: (1) the area of existing waterbird habitat likely lost to sea level rise by the end of the century (2100); and (2) the area of waterbird habitat potentially gained through restoration of lo‘i systems. Results show that, if loʻi offer similar or equivalent habitat value to Hawaiian waterbirds as conventionally managed wetlands, the restoration of loʻi would not only compensate for projected losses of wetland habitat due to sea level rise, but substantially contribute toward the recovery of endangered waterbirds that are currently habitat-limited. This study demonstrates capacity for contemporary Indigenous land management to address conservation and food-security needs in the Hawaiian Islands, as well as challenges of multi-objective land use and habitat restoration for endangered wetland-dependent fauna. This research further contributes toward a growing number of studies suggesting that Indigenous practices based on social-ecological frameworks offer potential to achieve sustainability and biodiversity goals simultaneously.
  • Item type: Item ,
    Cooperative breeding behaviors in the Hawaiian Stilt (Himantopus mexicanus knudseni)
    (Wiley, 2021-03-10) Dibben-Young, Arleone; Harmon, Kristen; Lunow-Luke, Arianna; Idle, Jessica; Christensen, Dain; Price, Melissa
    Cooperative breeding, which is commonly characterized by nonbreeding individuals that assist others with reproduction, is common in avian species. However, few accounts have been reported in Charadriiformes, particularly island-nesting species. We present incidental observations of cooperative breeding behaviors in the Hawaiian Stilt (Himantopus mexicanus knudseni), an endangered subspecies of the Black-necked Stilt (Himantopus mexicanus), during the 2012–2020 nesting seasons on the Hawaiian islands of O‘ahu and Moloka‘i. We describe two different behaviors that are indicative of cooperative breeding: (a) egg incubation by multiple adults; (b) helpers-at-the-nest, whereby juveniles delay dispersal and reproduction to assist parents and siblings with reproduction. These observations are the first published accounts of cooperative breeding in this subspecies and merit further investigation, as cooperative breeding may improve population viability of the endangered, endemic Hawaiian Stilt.
  • Item type: Item ,
    Seasonal patterns in nest survival of a subtropical wading bird, the Hawaiian Stilt (Himantopus mexicanus knudseni)
    (PeerJ, 2021-02-01) Harmon, Kristen; Wehr, Nathaniel; Price, Melissa
    Nest survival is influenced by where and when birds decide to breed. For ground-nesting species, nest-site characteristics, such as vegetation height and proximity to water, may impact the likelihood of nest flooding or depredation. Further, habitat characteristics, and thus nest survival, may fluctuate across the breeding season. The Hawaiian Stilt (‘Ae‘o; Himantopus mexicanus knudseni) is an endangered Hawaiian waterbird that nests in wetlands across the Hawaiian Islands. In this study, we used observational surveys and nest cameras to examine the impact of nest-site characteristics and day of nesting season on nest survival of the Hawaiian Stilt. Early nests had a higher chance of survival than late nests. For most of the nesting season, taller vegetation was correlated with increased nest survival, while shorter vegetation was correlated with increased nest survival late in the nesting season. Seasonal patterns in nest survival may be due to changes in parental behavior or predator activity. Nest depredation was responsible for 55% of confirmed nest failures and introduced mammals were the primary nest predators. Our study is the first to examine seasonality in nest survival of Hawaiian Stilts and suggests that, despite longer nesting seasons and year-round occupation of wetlands, late nesters in subtropical regions may have lower nest survival than early nesters, similar to trends observed in temperate regions.
  • Item type: Item ,
    Cooperative Breeding Behaviors in the Hawaiian Stilt (Himantopus mexicanus knudseni)
    (2021-03-17) Dibben-Young, Arleone; Harmon, Kristen; Lunow-Luke, Arianna; Idle, Jessica; Christensen, Dain; Price, Melissa
    Cooperative breeding, which is commonly characterized by non-breeding individuals that assist others with reproduction, is common in avian species. However, few accounts have been reported in Charadriiformes, particularly island-nesting species. We present incidental observations of cooperative breeding behaviors in the Hawaiian Stilt (Himantopus mexicanus knudseni), an endangered subspecies of the Black-necked Stilt (Himantopus mexicanus), during the 20122020 nesting seasons on the Hawaiian islands of O‘ahu and Moloka‘i. We describe two different behaviors that are indicative of cooperative breeding: (1) egg incubation by multiple adults; (2) helpers-at-the-nest, whereby juveniles delay dispersal and reproduction to assist parents and siblings with reproduction. These observations are the first published accounts of cooperative breeding in this subspecies and merit further investigation, as cooperative breeding may improve population viability of the endangered, endemic Hawaiian Stilt.