Geology topics

Theodore J. Zenzal

Publications and source records attributed to Theodore J. Zenzal.

At least 19 recordsLinked to original sources

USGS2026

Successes and opportunities for solutions-oriented conservation research: Lessons learned from avian science

Conservation science struggles with an ongoing divide between research and action. Given its history of broad public engagement and multi-scale management coordination, avian conservation typifies many of the challenges, successes, and opportunities across the broader field of conservation and is rich with examples that may guide solutions-oriented conservation science. In semi-structured focus groups composed of bird conservation scientists and practitioners from various backgrounds, we discussed the definition, characteristics, and examples of solutions-oriented conservation science. Our discussions highlighted several examples where successful application of avian conservation science led to change in programs, policy, regulations, and social systems, including several with co-benefits for local communities. These successes were characterized by communication, collaboration, and co-development with local communities, decision-makers, practitioners, and Indigenous communities. We identified remaining opportunities for improvement, including aligning incentives and priorities between research and practice, working across disciplines to mobilize solutions, dismantling barriers to inclusion, and emphasizing the importance of relationship-building in conservation science. We outline suggestions that researchers can use to incorporate these lessons from solutions-oriented avian conservation science into training and mentoring programs.

Conservation Science and Practice↗

USGS2026

Co-producing coastal bird research on the Gulf Coast through structured decision making (SDM) and constructed value of information (CVoI)

Conservation practitioners face the complex challenge of addressing global biodiversity threats within social-ecological systems with multiple jurisdictions, numerous interest groups, and changing environmental conditions. Bridging the research-to-implementation gap between scientists and managers, which integrates diverse perspectives that represent the variety of considerations impacting management outcomes can help to inform efficient and effective conservation. Avian conservation programs along the U.S. Gulf Coast exemplify these challenges, as management decisions must address diverse threats to declining coastal bird populations across large breeding, wintering, and migratory ranges while facing uncertainty surrounding the efficacy of large-scale strategies. This provides opportunities for improving management through co-produced research with structured decision making (SDM). We present a case study that demonstrates the application of co-production principles and SDM to collaboratively develop high-priority research questions informing effective avian conservation and management. Additionally, we applied a constructed value of information (CVoI) framework to identify and prioritize which uncertainties to reduce and better understand how research questions impact management actions. The integration of SDM’s five-step decision making framework ensured key principles of co-production were met, while co-production enhanced SDM outcomes by incorporating diverse perspectives and knowledge bases. CVoI further allowed participants to collectively determine final high-priority research questions in the face of complexity and uncertainty. Together, these approaches supported co-produced knowledge-generation, strategic hypothesis prioritization, and identification of research questions most likely to improve conservation decisions. This case study from the U.S. Gulf Coast demonstrates how co-produced research through SDM offers a broadly applicable approach for navigating ecological complexity and bridging the research-to-implementation gap in avian conservation.

Gulf Coast↗

USGS2026

Strategic approach for bird restoration evaluation - FY 2025 annual report

The Deepwater Horizon oil spill (hereafter “ spill ”) resulted in an estimated loss of 56,141–102,399 birds across 93 species along the U.S. Gulf of America coast. Injured species included those that nest locally along the northern Gulf of America coast as well as species that nest hundreds or thousands of kilometers outside of the region. The breadth of injury and the expansive geographic distribution of birds affected by the spill necessitated implementation of numerous and diverse projects designed to restore the injury of all affected bird species. As of September 2025, the Trustees, who are authorized to act on behalf of the public to restore injuries caused by the spill , have approved 39 projects, amounting to >60% of the total funds specifically allocated for bird restoration (i.e., Bird Restoration Type funding). Strategic allocation of remaining Bird Restoration Type funding is necessary to ensure that restoration of all injured bird species is achieved. An essential component of planning for future restoration is understanding the progress made from restoration actions conducted to date. The purpose of this project is to develop a plan that assesses the current restoration progress for each of the 93 injured species based on available data. The restoration assessment plan will be derived from a data gap analysis that identifies species for which data may be insufficient to assess restoration progress. This project will also allow Trustees to review and update the indicators of restoration success developed for injured bird species (e.g., population counts, reproduction metrics) that are used to evaluate restoration progress.

Annual Report↗

USGS2025

Effectiveness of stewardship and management strategies to conserve coastal bird populations in the northern Gulf of Mexico: A literature review

Shorebirds, seabirds, and wading birds (hereafter coastal birds) have experienced considerable losses over the last century and require proactive conservation management to stabilize or grow populations. Habitat loss and/or degradation and human disturbance are among the most urgent threats faced by coastal bird populations. Identifying effective conservation management techniques to mitigate these threats is of great interest in the northern Gulf of Mexico (nGoM), a region that provides important habitat during the entire life cycle of resident birds and an essential breeding, wintering, and stopover site for migratory birds. A suite of 35 coastal birds have been identified as priority species for multi-scale conservation monitoring in this region by the Gulf of Mexico Avian Monitoring Network (GoMAMN). This review focuses on impacts of human disturbance and anthropogenic habitat loss and/or degradation on coastal birds and effectiveness of the management strategies implemented to mitigate them, with the goal of informing nGoM management. Our review found that human disturbance was best alleviated by simultaneously deploying complementary stewardship techniques (e.g., signs, fencing, steward patrols, education and community involvement, and beach closures to humans, dogs, and vehicles). However, the relative efficacy of each individual technique is unclear given that only 13% of human disturbance management studies and 38% of habitat management studies have been conducted in the nGoM region. Given the nature of coastal bird habitat and associated risks from sea level rise and human development, most habitat management studies encouraged strategic applications of beach renourishment, limitations on beach raking, as well as site- and species-specific restoration strategies. Studies demonstrated that successful management of coastal birds in the nGoM combined these approaches, employing complementary and adaptive strategies over extended periods.

Journal of Field Ornithology↗

USGS2025

Piping Plover home ranges do not appear to be impacted by restoration of barrier islands and headlands

Restoration of barrier island and headland habitats can alter existing and create new habitats, which may impact wildlife occupying these areas such as the threatened Piping Plover ( Charadrius melodus ). We used resight data from banded birds to develop minimum convex polygon (MCP) and kernel density estimates (KDE) of individual Piping Plover home ranges to investigate whether changes in habitat use resulted from restoration activities at Whiskey Island and Caminada Headland, Louisiana. We quantified home range areas for each season and compared changes among pre-restoration, active restoration, and post-restoration phases at each site. We had sufficient sample sizes from Whiskey Island to compare home ranges derived by MCP during the pre-restoration phase to the active restoration phase. However, we did not have enough resight data to analyze post-restoration phase by MCP or any phase by KDE at Whiskey Island. For Caminada Headland, we were able to compare all phases of restoration using MCP, but only had sufficient data to compare pre-restoration and active restoration phases using KDE. Aside from one significant decrease in core (50% isopleth) home range at Caminada Headland when comparing MCPs between post-restoration (∼8 ha) and pre-restoration (∼11 ha) phases, we found no other differences in home range size across phases at either of our study sites. The sum of all evidence generally indicating no change to Piping Plover home range size suggests that barrier island and headland restoration did not have significant positive or negative impacts. The weak response to restoration activities further suggests that birds are using similar or smaller amounts of habitat after restoration is complete and may not need to expand their foraging range following restoration. Further study can help to understand how species of conservation concern respond to coastal restoration efforts, which is critical for establishing comprehensive conservation strategies aimed at species recovery.

BioRxiv↗

USGS2025

Understanding abundances and behaviors of shorebirds in coastal Louisiana

Barrier islands provide resources and ecological services that are integral to economic and environmental interests, such as protection of coastal infrastructure and provision of wildlife habitat. Over time, barrier islands may become eroded and experience land loss, which can require management actions to restore island integrity. Barrier island restoration can create or modify habitats, which can impact the organisms depending on them. Our objective was to understand how the abundance and behaviors of a suite of shorebird species responded to restoration and habitat factors at two restored sites in coastal Louisiana (USA). For five focal species, we used abundance from the breeding and non-breeding seasons as well as breeding, foraging, and maintenance behaviors as response variables in boosted regression tree models to determine the importance of various geospatial and remotely sensed predictor variables related to restoration. Across sites and species, remotely sensed variables, particularly a brightness index, tended to be more important than restoration phases as predictors of bird abundance and behavior. Our results suggest that sediment composition, moisture, and vegetative cover are related to shorebird coastal habitat selection, although the direction and strength of relationships differ among these variables and our focal species. Tying these remote sensing metrics to restoration design and management actions can help land managers better understand factors that attract and benefit birds. Additional research can advance understanding in how remote sensing can be used to monitor the availability of functional habitats for shorebirds.

BioRxiv↗

USGS2025

Variation in detection distance of Eastern Black Rail (Laterallus jamaicensis jamaicensis) vocalizations by autonomous recording units

Autonomous recording units (ARUs) are an emerging technology that allows for passive monitoring of soniferous animals and soundscapes. Over the past decade, ARUs have become a popular tool for monitoring birds for their potential to reduce the labor and costs of traditional in-person sampling procedures. However, uncertainty surrounding factors affecting detection of avian taxa using ARUs can inhibit their monitoring efficacy. Eastern Black Rails ( Laterallus jamaicensis jamaicensis ) are a secretive marsh bird listed as a federally threatened species in the U.S.A. Eastern Black Rail vocalizations are difficult to detect by field personnel, and numerous in-person surveys can be required to confirm their presence at a site. While ARUs are an alternative for detecting Eastern Black Rails, it is unknown at what maximum distance an ARU can detect their vocalizations. We evaluated factors affecting the detection distance of simulated vocalizations for ARUs in four marsh vegetation types under a range of environmental conditions. Detection distances varied across models, vocalization and vegetation types, and call volume. Kickeedo vocalizations were detected at greater distances, and detection distances increased for all vocalization types in open vegetation. High relative humidity increased detection distances, while louder background noise decreased detection distances. High wind speeds in cordgrass ( Spartina spp .) decreased detection probability disproportionately relative to other vegetation types. Based on these results, considerations of survey area, vegetation type, and site condition can allow land managers and researchers to optimize Eastern Black Rail monitoring using ARUs. Given the substantial staff time needed to monitor this species, ARUs may increase the likelihood of detection and provide an efficient alternative to in-person monitoring.

Waterbirds↗

USGS2025

Early season tropical cyclones affect birds breeding on a barrier island

Animal populations often experience acute natural disturbances, most of which are connected to short—term weather events. Occurrences of early—season tropical cyclones during the peak of the avian breeding season are likely to increase with climate change, which can substantially impact populations of coastal breeding birds at multiple scales. To understand the acute impacts of severe tropical cyclones, we investigated how abundances of breeding birds changed before and after 4 early season named tropical cyclones on a barrier island in the Gulf of Mexico. We detected a change in pre— versus post—storm numbers of breeding birds after 2 out of 4 storms between 2015–2020. Following Tropical Storm Cindy and Hurricane Barry, significant declines in breeding adults ranged from a reduction of 32 Willets ( Tringa semipalmata ) to 105 Wilson’s Plover ( Anarhynchus wilsoni a) and 18 Willets to 1,794 Black Skimmer ( Rynchops niger ), respectively. The lack of response following 2 storms was likely due to the location of the storms relative to the island. Following the 2 storms that did elicit a response by breeding birds, we observed lower abundances in the majority of species after the storm passed. Species life histories and habitat restoration might explain the species—specific responses we observed. Our study documents occurrences of early—season tropical cyclones negatively affecting coastal breeding birds, which could be exacerbated with sea level rise. Additionally, our findings may provide insights regarding island design and nest susceptibility to flooding events, which may aid land managers as well as conservation and restoration planners.

Louisiana↗

USGS2024

Ticks without borders: Microbiome of immature neotropical tick species parasitizing migratory songbirds along northern Gulf of Mexico

Introduction: The long-distance, seasonal migrations of birds make them an effective ecological bridge for the movement of ticks. The introduction of exotic tick species to new geographical regions can cause the emergence of novel tick-borne pathogens. This study examined the prevalence of exotic tick species parasitizing migratory songbirds at stopover sites along the northern Gulf of Mexico using the mitochondrial 12S rRNA gene. Methods: Overall, 421 individual ticks in the genera Amblyomma , Haemaphysalis , and Ixodes were recorded from 28 songbird species, of which Amblyomma and Amblyomma longirostre were the most abundant tick genera and species, respectively. A high throughput 16S ribosomal RNA sequencing approach characterized the microbial communities and identified pathogenic microbes in all tick samples. Results and discussion: Microbial profiles showed that Proteobacteria was the most abundant phylum. The most abundant pathogens were Rickettsia and endosymbiont Francisella , Candidatus Midichloria , and Spiroplasma . Permutation multivariate analysis of variance revealed that the relative abundance of Francisella and Rickettsia drives microbial patterns across the tick genera. We also noted a higher percentage of positive correlations in microbe-microbe interactions among members of the microbial communities. Network analysis suggested a negative correlation between a) Francisella and Rickettsia and, b) Francisella and Cutibacterium . Lastly, mapping the distributions of bird species parasitized during spring migrations highlighted geographic hotspots where migratory songbirds could disperse ticks and their pathogens at stopover sites or upon arrival to their breeding grounds, the latter showing mean dispersal distances from 421–5003 kilometers. These findings spotlight the potential role of migratory birds in the epidemiology of tick-borne pathogens.

Alabama, Louisiana↗

USGS2024

Coastal breeding bird phenology on the dredged-material islands of the Baptiste Collette Bayou, US Army Corps of Engineers, New Orleans District, Louisiana

Coastal bird populations in North America have experienced significant population declines over the past four decades, and many species have become dependent upon human-made islands and other sediment-based habitats created through dredged material deposition. We monitored the breeding phenology of coastal bird populations utilizing dredged-material islands and open depositional areas in the Baptiste Collette Bayou in coastal Louisiana. Monitoring began in early May, prior to when most coastal species begin nesting, and continued through late August, when most breeding activity has ceased. Semimonthly surveys included area searches by foot and boat. Two deposition areas and one island supported large numbers of foraging, roosting, or breeding birds; surveys on these areas included using spotting scopes to identify species and count nests or young. Six islands and two open deposition areas were monitored. We also collected high-definition and lidar imagery using an uncrewed aerial system (UAS) in June, during peak nesting season. We recorded 77,474 cumulative detections of 68 species. Virtually all colonial nesting birds (terns and skimmers) nested on Gunn Island in 2021. We discuss these results in the context of dredged-material deposition by the US Army Corps of Engineers, New Orleans District, and offer recommendations for management of these areas.

Louisiana↗

USGS2024

Asynchronous movement patterns between breeding and stopover locations in a long-distance migratory songbird

The species-specific migratory patterns and strategies of many songbirds remain unknown or understudied, as research in animal ecology is biased toward the breeding period, with the fewest studies on the migratory period across taxa. Identifying large-scale spatiotemporal migratory patterns is challenging, as individuals within a species may vary in their migratory behavior and strategies. The Yellow Warbler ( Setophaga petechia ) is a Nearctic-Neotropical migrant that is relatively well studied during the breeding season, but its species-wide migratory patterns remain understudied. Our aim in studying Yellow Warbler movement ecology was to characterize temporal migration patterns during fall migration. We sought to determine the temporal migration pattern among breeding locations, as determined by the hydrogen stable isotope values in feather samples collected at disjunct (~2000 km) stopover sites in the Gulf of Maine (n = 50) and the Gulf of Mexico (n = 150). We used a similarity matrix to group individuals into a geographic cluster by breeding location, which was then used as the response variable in a modeling analysis. Our results provide evidence that Yellow Warblers exhibit an asynchronous, type 1 temporal migration pattern with southern breeding populations initiating migration prior to northern populations. Using hydrogen isotopes, we identified the temporal migration patterns between geographic clusters, representing an individual’s breeding location, and stopover sites along the Gulf of Maine and Gulf of Mexico, which fills a gap in understanding Yellow Warbler migration ecology.

Avian Conservation and Ecology↗

USGS2023

Springing forward: Migrating songbirds catch up with the start of spring in North America

In temperate regions, the annual pattern of spring onset can be envisioned as a ‘green wave’ of emerging vegetation that moves across continents from low to high latitudes, signifying increasing food availability for consumers. Many herbivorous migrants ‘surf’ such resource waves, timing their movements to exploit peak vegetation resources in early spring. Although less well studied at the individual level, secondary consumers such as insectivorous songbirds can track vegetation phenology during migration as well. We hypothesized that four species of ground-foraging songbirds in eastern North America—two warblers and two thrushes—time their spring migrations to coincide with later phases of vegetation phenology, corresponding to increased arthropod prey, and predicted they would match their migration rate to the green wave but trail behind it rather than surfing its leading edge. We further hypothesized that the rate at which spring onset progresses across the continent influences bird migration rates, such that individuals adjust migration timing within North America to phenological conditions they experience en route . To test our hypotheses, we used a continent-wide automated radio telemetry network to track individual songbirds on spring migration between the U.S. Gulf Coast region and northern locations closer to their breeding grounds. We measured vegetation phenology using two metrics of spring onset, the spring index first leaf date and the normalized difference vegetation index (NDVI), then calculated the rate and timing of spring onset relative to bird detections. All individuals arrived in the southeastern United States well after local spring onset. Counter to our expectations, we found that songbirds exhibited a ‘catching up’ pattern: Individuals migrated faster than the green wave of spring onset, effectively closing in on the start of spring as they approached breeding areas. While surfing of resource waves is a well-documented migration strategy for herbivorous waterfowl and ungulates, individual songbirds in our study migrated faster than the green wave and increasingly caught up to its leading edge en route . Consequently, songbirds experience a range of vegetation phenophases while migrating through North America, suggesting flexibility in their capacity to exploit variable resources in spring.

Journal of Animal Ecology↗

USGS2023

Local weather and endogenous factors affect the initiation of migration in short- and medium-distance songbird migrants

Migratory birds employ a variety of mechanisms to ensure appropriate timing of migration based on integration of endogenous and exogenous information. The cues to fatten and depart from the non-breeding area are often linked to exogenous cues such as temperature or precipitation and the endogenous program. Shorter distance migrants should rely heavily on environmental information when initiating migration given relatively close proximity to the breeding area. However, the ability to fatten and subsequently depart may be linked to individual circumstances, including current fuel load and body size. For early and late departing migrants, we investigate effects of temperature, precipitation, lean body mass, fuel load and day of year on the initiation of migration (i.e. fuel load and departure timing) from the non-breeding region by analyzing 21 years of banding data for four species of short- and medium-distance migrants. Temperatures at the non-breeding area were related to temperatures at potential stopover areas. Despite local cues being predictive of conditions further north, the amount variation explained by local weather conditions in our models differed by species and temporal period but was low overall (< 33% variation explained). For each species, we also compared lean body mass and fuel load between early and late departing migrants, which showed mixed results. Our combined results suggest that most individuals migrating short or medium distances in our study did not time the initiation of migration with local predictive cues alone, but rather other factors such as lean body mass, fuel load, day of year, which may be a proxy for the endogenous program, and those beyond the scope of our study also influenced the initiation of migration. Our study contributes to understanding which factors influence departure decisions of short- and medium-distance migrants as they transition from the non-breeding to the migratory phase of the annual cycle.

Louisiana↗

USGS2023

Structured decision making to prioritize regional bird monitoring needs

Conservation planning for large ecosystems has multiple benefits but is often challenging to implement because of the multiple jurisdictions, species, and habitats involved. In addition, decision making at large spatial scales can be hampered because many approaches do not explicitly incorporate potentially competing values and concerns of stakeholders. After the Deepwater Horizon oil spill, establishing baselines was challenging because of (1) variation in study designs, (2) inconsistent use of explicit objectives and hypotheses, (3) inconsistent use of standardized monitoring protocols, and (4) variation in spatial and temporal scope associated with avian monitoring projects before the spill. Herein, we show how the Gulf of Mexico Avian Monitoring Network members used structured decision making to identify bird monitoring priorities. We used multiple tools and techniques to clearly define the problem and stakeholder objectives and to identify bird monitoring priorities at the scale of the entire northern Gulf of Mexico region. Although our example is specific to the northern Gulf of Mexico, this approach provides an example of how stakeholder values can be incorporated into the coordination process of broad-scale monitoring programs to address management, restoration, and scientific questions in other ecosystems and for other taxa.

INFORMS Journal on Applied Analytics↗

USGS2023

A Buteo sp. hawk predates a hummingbird (Trochilidae) during autumn migration

Predation can play a significant role on survival during migration as birds find themselves competing for resources in unfamiliar habitats. Here we describe the first documented observation of a Buteo platypterus (Broad-winged Hawk) predating an Archilochus colubris (Ruby-throated Hummingbird) during autumn migration. To our knowledge, this is the first documented record of any Buteo sp. hawk predating any Trochilidae (hummingbird). While predation on hummingbirds likely represents a minor source of mortality, identifying sources of predation and mortality is important in understanding the risk of migration for any species.

Southeastern Naturalist↗

USGS2023

An introduction to the evaluation of restoration for avian species at Caminada Headland and Whiskey Island in Louisiana

Barrier islands are crucial for protecting Louisiana’s coastal communities and ecosystems as they reduce coastal erosion and help safeguard native flora and fauna. Along the Louisiana shoreline, these islands are mostly long and thin, running parallel to the shoreline. The islands typically consist of the following components: 1) a sandy beach facing the Gulf of Mexico; 2) vegetated and non-vegetated dunes; 3) overwash areas; 4) swales; 5) upland shrubs; 6) wetland shrubs, such as black mangrove (Avicennia germinans); 7) backbay marshes; and 8) tidal flats. Dune vegetation and vegetation along the back-barrier help bind and collect sediment, which create and maintain wetlands on the north side of the barrier islands. Barrier islands provide various ecological services including: 1) buffering waves to decrease storm impacts; 2) protecting wetlands that provide suitable reproductive habitat and nursery grounds for fish and shellfish; and 3) providing critical habitat for birds and sea turtles (Barbier 2013).

Louisiana↗

USGS2023

Conclusions of evaluation of restoration for avian species at Caminada Headland and Whiskey Island, Louisiana

We conducted various analyses to determine the impact of coastal restoration on several focal avian species at Caminada Headland and Whiskey Island, Louisiana. We assessed if restoration affected avian use of restored sites by determining overall habitat changes, occupancy trends, and impacts of construction activities. Here, we summarize our findings from Chapters 2-9. For more details and additional information, please see Chapters 1-9 in this report.

Louisiana↗

USGS2023

Site occupancy of focal shorebird species at Whiskey Island and Caminada Headland, Louisiana 2012–2020

Coastal restoration through island construction and augmentation is an increasingly common management method in the northern Gulf of Mexico, but evaluating the impacts to shorebird species is difficult. Shorebirds are mostly migratory and many aspects of their life history, including reproduction in some species, occur in other places. In addition, counts or observations of shorebirds made at any given time represent only a portion of the population and that proportion may change with site conditions such as time of day and weather. Dynamic occupancy models can account for imperfect detection and produce estimates of the proportion of area occupied over time as a way to track trends in bird utilization over time. In this chapter we report on occupancy trends for five focal shorebird species from Caminada Headland and Whiskey Island: American Oystercatcher ( Haematopus palliatus ), Piping Plover ( Charadrius melodus ), Red Knot ( Calidris canutus ), Snowy Plover ( Charadrius nivosus ), and Wilson’s Plover ( Charadrius wilsonia ). We examined up to nine years of surveys at the two sites to model long-term trends in occupancy rates from a period spanning before, during, and after restoration. Our objective was to determine if there was change in occupancy over time (trend) during the restoration period. Field sampling was conducted as described in Chapter 1 for the five focal species in this chapter. To create spatial units for occupancy analysis we used a grid of 53 unique cells at Caminada Headland and 26 unique cells at Whiskey Island. All observations of the species were located into spatial units using GIS and presence of each species in each cell was determined for each visit within a sampling season. Sampling seasons were defined for species as the period of time where they were most likely to be using the study area, and corresponded with wintering (August–May), breeding (April–August), or staging (March–October). We did not include covariates for initial occupancy or colonization and site survival because these were small sites with homogenous habitat. We did account for time of year within a season by treating survey date as a covariate of detection probability and allowed it to vary throughout the season. We tested for a trend in occupancy over time by determining if the estimated slope through the series of annual occupancy estimates was significantly different from 0. We conducted 153 total surveys at Caminada Headland from 11 January 2013 to 5 June 2019, and 213 total surveys at Whiskey Island from 7 August 2012 to 19 August 2020. The number of surveys per year varied by species and site and range from 6–23 per species annually at Caminada Headland and 11–28 per species annually at Whiskey Island. Occupancy trends were able to be assessed for all species at both sites, with the exception of the American Oystercatcher, which were only observed in sufficient numbers to estimate occupancy at Whiskey Island. We found a significant positive trend in occupancy from 0.325 to 0.741 for American Oystercatcher at Whiskey Island. There was no significant trend in Piping Plover occupancy at Caminada Headland where occupancy was consistently high (0.910 to 0.947). At Whiskey Island, Piping Plover occupancy estimates increased from 0.574 to 0.908 during the study period which was a significant increase. At Caminada Headland and Whiskey Island Red Knot occupancy varied from 0.482 to 0.891 and 0.350 to 0.742, respectively, but showed no significant trend over the study period. Snowy Plover occupancy at Caminada Headland increased significantly from 0.295 to 0.785 over the study period. Snowy Plover occupancy also increased significantly at Whiskey Island from 0.442 to 0.906. Wilson’s Plover occupancy declined slightly during the study period from 0.946 to 0.935 at Caminada Headland, and from 0.858 to 0.736 at Whiskey Island, but the decline was not significant at either site. We found no evidence that occupancy declined significantly for any of the species during the period prior to, during, and after restoration. We did find a significant increasing trend in occupancy for Snowy Plover at Caminada Headland and a significant increasing trend for American Oystercatcher, Piping Plover, and Snowy Plover at Whiskey Island. Our modeling results indicate that sampling such as this is sufficient for occupancy modeling and can provide a robust metric for comparison over time or among sites. In future research we plan to investigate the sample size needed to detect a trend. We are currently conducting a power analysis to determine the minimum amount of sampling necessary to have power to detect a trend based on the detection probabilities from this study.

Report↗