Intensive agriculture in the Prairie Pothole Region of Iowa, USA has resulted in significant wetland drainage and wildlife population declines. However, easement programs are increasingly used to protect and restore wetlands and revitalize biodiversity. Short-term responses (i.e., 1-5 years) of birds to wetland restorations are well-documented, but long-term trends are less understood. We surveyed wetland easements in Iowa during 2007-2009 and 2022-2023 to assess changes in breeding bird communities and occupancy for conservation-priority species. We conducted bird point counts and vegetation surveys at 55 wetland easements. We used species accumulation curves to estimate overall breeding bird richness by guild, and site-occupancy models to estimate occupancy for 20 conservation-priority species. Species richness remained stable between time periods, but community composition shifted, with fewer grassland and more forest bird species despite no change in woody vegetation cover estimates (2007-2009: 3.2%, standard deviation [SD] = 5.9; 2022-2023: 3.1%, SD = 3.8). Occupancy for most species at wetland easements remained stable over time; however, 4 species declined (e.g., Cistothorus stellaris [Sedge Wren]). Six grassland bird species (e.g., Sturnella magna [Eastern Meadowlark]) exhibited positive or stable occupancy trends. Forest-dependent species generally maintained or increased in occupancy (e.g., Icterus galbula [Baltimore Oriole]). Increased forest bird richness despite stable woody vegetation cover may indicate changing structural characteristics as existing forests mature, whereas management to control woody encroachment at wetland easements may explain our observations of stable forest bird occupancy. Wetland easements may be strongholds for some grassland bird species, which are in precipitous decline across North America. Our study highlights the importance of wetland easements in an agricultural landscape to breeding bird communities and emphasizes the value of continued monitoring to track changes over time. center dot Wetland easements in the intensely agricultural landscape of Iowa create habitats for many breeding bird species, but the way birds use these easements over time is not well known.center dot Our goals were to determine how breeding bird communities and occupancy for species of conservation concern have changed at wetland easements across 16 years.center dot We surveyed breeding birds during 2007-2009 and 2022-2023.center dot The number of bird species at wetland easements was stable across time periods, but species composition changed, with fewer grassland species, and more forest bird species.center dot Occupancy of most species remained stable; however, some grassland bird species had stable or increased occupancy in 2022-2023 despite widespread declines across North America.center dot As wetland easements age, they continue to promote breeding bird occupancy, including non-wetland-dependent species, however, additional studies on nest success and survival in this system would be beneficial. La agricultura intensiva en la Regi & oacute;n de las Praderas Potholes en Iowa, EUA, ha provocado un drenaje significativo de humedales y una disminuci & oacute;n en las poblaciones de fauna silvestre. Sin embargo, los programas de servidumbres se utilizan cada vez m & aacute;s para proteger y restaurar humedales y revitalizar la biodiversidad. Las respuestas a corto plazo (i.e., 1-5 a & ntilde;os) de las aves a la restauraci & oacute;n de humedales est & aacute;n bien documentadas, pero las tendencias a largo plazo son menos comprendidas. Estudiamos servidumbres de humedales en Iowa durante 2007-2009 y 2022-2023 para evaluar los cambios en las comunidades de aves reproductoras y la ocupaci & oacute;n de especies prioritarias para la conservaci & oacute;n. Realizamos conteos de aves por puntos y censos de vegetaci & oacute;n en 55 servidumbres de humedales. Utilizamos curvas de acumulaci & oacute;n de especies para estimar la riqueza total de aves reproductoras por gremio, y modelos de ocupaci & oacute;n de sitios para estimar la ocupaci & oacute;n de 20 especies prioritarias para la conservaci & oacute;n. La riqueza de especies se mantuvo estable entre los periodos de tiempo, pero la composici & oacute;n comunitaria cambi & oacute;, con menos especies de aves de pastizal y m & aacute;s especies de aves de bosque, a pesar de que no hubo cambios en la cobertura estimada de vegetaci & oacute;n le & ntilde;osa (2007-2009: 3.2%, desv & iacute;o est & aacute;ndar [DE] = 5.9; 2022-2023: 3.1%, DE = 3.8). La ocupaci & oacute;n de la mayor & iacute;a de las especies en las servidumbres de humedales se mantuvo estable a lo largo del tiempo; sin embargo, 4 especies disminuyeron (e.g., Cistothorus stellaris). Seis especies de aves de pastizal (e.g., Sturnella magna) mostraron tendencias positivas o estables en la ocupaci & oacute;n. Las especies dependientes del bosque generalmente mantuvieron o aumentaron su ocupaci & oacute;n (e.g., Icterus galbula). El aumento en la riqueza de aves de bosque, a pesar de la cobertura estable de vegetaci & oacute;n le & ntilde;osa, puede indicar cambios en las caracter & iacute;sticas estructurales a medida que los bosques existentes maduran, mientras que el manejo para controlar la invasi & oacute;n le & ntilde;osa en las servidumbres de humedales puede explicar nuestras observaciones de ocupaci & oacute;n estable de aves de bosque. Las servidumbres de humedales pueden ser sitios importantes para algunas especies de aves de pastizal, que est & aacute;n en fuerte declive en toda Am & eacute;rica del Norte. Nuestro estudio resalta la importancia de las servidumbres de humedales en un paisaje agr & iacute;cola para las comunidades de aves reproductoras y enfatiza el valor del monitoreo continuo para rastrear cambios a lo largo del tiempo.

The umbrella species concept is often used as a tool to guide management decisions and focus efforts towards one focal species whose habitat needs overlap that of other species. We assessed this concept in the context of an agriculturally dominant landscape using one of the most well-studied avian species in North America as a target for conservation efforts: Northern Bobwhite (Colinus virginianus). This species is often viewed as an umbrella species for grassland and shrubland bird conservation throughout its native range due to its complex, year-round habitat requirements. We assessed the influence of Northern Bobwhite habitat management on six songbird species of conservation concern in Iowa by evaluating similarities and differences in habitat associations between each species. Our objectives were to (1) assess which vegetation characteristics were most strongly associated with Northern Bobwhite occupancy and (2) evaluate whether those characteristics were also associated with abundance of the focal songbird species. We used occupancy and N-mixture models to assess relationships between vegetation characteristics and Northern Bobwhite occupancy and songbird abundance, respectively. We found that the vegetation characteristics most strongly associated with Northern Bobwhite occupancy probability were the amounts of closed canopy forest, early successional woody vegetation, non-vegetated areas, and percent cover of bare ground. We found that for some of these covariates, including the amounts of forest and non-vegetated area, the effect on focal songbird species abundance aligned with Northern Bobwhite occupancy. For others, including the amount of early successional woody vegetation, the effects differed. This assessment of overlap and variability in habitat associations suggests that Northern Bobwhite-targeted management can provide benefits to other grassland and shrubland birds, but may also come with some trade-offs. This work adds to existing literature, further highlighting the nuances of the umbrella species concept in that land management benefits from the assessment of trade-offs and inclusion of local community dynamics.

Consideration of the full annual cycle population dynamics can provide useful insight for conservation efforts, but collecting data needed to estimate demographic parameters is often logistically difficult. For species that breed in remote areas, monitoring is often conducted during migratory stopover or at nonbreeding sites, and the recruitment rate of new breeding adults can be difficult to estimate directly. Here, we present an integrated population model that uses mark-resight and count data to estimate survival probability, population growth rate, and recruitment rate for an Arctic-breeding shorebird of conservation concern, the red knot (Calidris canutus rufa), from data collected during spring stopover in Delaware Bay, USA, from 2005 to 2018. At this site, red knots feed primarily on the eggs of spawning horseshoe crabs (Limulus polyphemus), a legally harvested species. We used this model to estimate the relationship between horseshoe crab abundance and red knot demographics, which informed a recent revision to the framework used to establish horseshoe crab harvest regulations. Our analysis indicates that the red knot population was most likely stable from 2005 to 2018 (average lambda = 1.03, 95% credible interval [CRI]: 0.961, 1.15) despite low recruitment rates (average rho = 0.088, 95% CRI: 0.012, 0.18). Adult survival probability was positively associated with horseshoe crab abundance in the same year (beta = 0.35, 95% CRI: 0.09, 0.63), but we found no effect of horseshoe crab abundance two years previously on recruitment of new adults (beta = -0.08, 95% CRI: -0.41, 0.38). Our approach demonstrates the utility of integrated population models for understanding population dynamics, even when data are only available from migratory stopover monitoring.

Understanding the effects of migratory stopover site conditions on both demographic rates and migratory behaviors is critical for interpreting changes in passage population sizes at stopover sites and predicting responses to future changes and conservation actions. We used a Bayesian formulation of the open robust design model to analyze mark-resight observations of three migratory shorebird species using Delaware Bay, USA during spring stopover from 2005 to 2018. We tested for an effect of stopover food availability and weather conditions on survival probability and the probability of returning to this site in the next year and found species differences in these relationships. After years with greater food availability, red knot Calidris canutus rufa had higher survival probability but ruddy turnstone Arenaria interpres were more likely to return to the site. Estimates of within-year probabilities of arrival and persistence at the stopover site showed relatively consistent migration schedules for ruddy turnstone, but more interannual variation for red knot and sanderling Calidris alba. Shorebird use of this site typically peaked during May 26-28, but the estimated proportion of the population present during this period varied dramatically among years for red knot (range: 0.07-0.59) but less so for ruddy turnstone and sanderling. This demonstrates that both the proportion of the flyway population using this stopover site and the proportion present during a given sampling period vary among years, and both should be considered in analyzing and interpreting monitoring data. Stopover conditions can influence both migratory behavior and demographics, underscoring the importance of flyway-wide monitoring.

Conservation BiologyVolume 35, Issue 5 p. 1683-1685 COMMENT Decision context as a necessary component of population viability analysis assessments: response to Chaudhary and Oli 2020 Abigail J. Lawson, Corresponding Author Abigail J. Lawson alawson@usgs.gov orcid.org/0000-0002-2799-8750 U.S. Geological Survey, Eastern Ecological Science Center at Patuxent Research Refuge, Laurel, Maryland, USA Correspondence Abigail J. Lawson, U.S. Geological Survey, Email: alawson@usgs.govSearch for more papers by this authorBrian Folt, Brian Folt orcid.org/0000-0003-2278-2018 School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USASearch for more papers by this authorAnna M. Tucker, Anna M. Tucker orcid.org/0000-0002-1473-2048 U.S. Geological Survey, Eastern Ecological Science Center at Patuxent Research Refuge, Laurel, Maryland, USASearch for more papers by this authorFrancesca Erickson, Francesca Erickson School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USASearch for more papers by this authorConor P. McGowan, Conor P. McGowan orcid.org/0000-0002-7330-9581 U.S. Geological Survey, Florida Cooperative Fish & Wildlife Research Unit, University of Florida, Florida, Gainesville, USASearch for more papers by this author Abigail J. Lawson, Corresponding Author Abigail J. Lawson alawson@usgs.gov orcid.org/0000-0002-2799-8750 U.S. Geological Survey, Eastern Ecological Science Center at Patuxent Research Refuge, Laurel, Maryland, USA Correspondence Abigail J. Lawson, U.S. Geological Survey, Email: alawson@usgs.govSearch for more papers by this authorBrian Folt, Brian Folt orcid.org/0000-0003-2278-2018 School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USASearch for more papers by this authorAnna M. Tucker, Anna M. Tucker orcid.org/0000-0002-1473-2048 U.S. Geological Survey, Eastern Ecological Science Center at Patuxent Research Refuge, Laurel, Maryland, USASearch for more papers by this authorFrancesca Erickson, Francesca Erickson School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USASearch for more papers by this authorConor P. McGowan, Conor P. McGowan orcid.org/0000-0002-7330-9581 U.S. Geological Survey, Florida Cooperative Fish & Wildlife Research Unit, University of Florida, Florida, Gainesville, USASearch for more papers by this author First published: 18 August 2021 https://doi.org/10.1111/cobi.13818Citations: 1 Article Impact Statement: : Decision context is necessary to include in population viability analysis quality assessment to ensure transparency in conservation decisions. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Supporting Information Filename Description cobi13818-sup-0001-Appendix.pdf142 KB Appendix S1. Questions used to prospectively guide the development and documentation of population viability analysis (PVA) models. The question set contains four major categories. The Decision Context (A, questions i–v) category reflects an expansion on the original questions developed by Chaudhary and Oli (2020), which included the Background, Model, and Analysis Quality categories (B–D, questions 1−32). Questions within the Decision Context (A) category evaluate if decision context attributes and model limitations are clearly described, as well as the relevancy of model outputs and potential management actions or scenarios to decision makers. Background Quality (B) comprises information on the study species, data collection, and objectives. Model Quality (C) evaluates parameter estimation procedures, appropriateness of model structure given the species' life history and available data, and the inclusion of stochasticity (e.g., demographic, environmental), threats, and management actions. Analysis Quality (D) evaluates components of the simulation framework, including the appropriateness of the time horizon and number of iterations, sensitivity analyses, and reporting of PVA metrics, including growth rate (lambda) and extinction probabilities. This list is not exhaustive but represents many common elements across decision-support PVAs specifically tailored to inform a management decision as well as heuristic PVAs in which the primary motivation may be for learning. Finally, we recognize that not all questions may be relevant to all PVA types; for example, Decision Context questions are likely less relevant for heuristic compared to decision support. Therefore, we intend for this list to be used prospectively to guide the development and documentation of PVAs, rather than a post-hoc assessment of quality, given the difficulty in establishing common metrics across PVAs developed for extremely different purposes.Appendix S2. List of the 10 highest- and lowest-ranked population viability analysis (PVA) papers (n = 160 total) appraised by Chaudhary and Oli (2020), as indicated in the C&O Rank column. We reviewed these 20 papers and classified each based on their Model Type, which describes the primary motivation for PVA development. If the PVA was constructed to directly inform a management decision, we classified it as a "Decision Support" model, while PVAs developed primarily for learning purposes (e.g., to better understand population dynamics or relative threat risks) were classified as "Heuristic." If a distinction could not be made, we classified it as "Unclear." Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article. Volume35, Issue5October 2021Pages 1683-1685 RelatedInformation

Conservation planning for rare and threatened species is often made more difficult by a lack of research and monitoring data. In such cases, managers may rely on qualitative assessments of species risk that lack explicit acknowledgement of uncertainty. Snakes are a group of conservation concern that are also notoriously difficult to monitor. Here, we demonstrate a quantitative population projection for a data‐deficient species, the Puerto Rican boa ( Chilabothrus inornatus ) using expert knowledge and published information about species life history and threats to persistence. Using this model, we simulated population dynamics over 30 years under four scenarios of future urbanization and found that there was an increased probability of population decline as urbanization rates increased. We conduct a sensitivity analysis to evaluate the sensitivity of outcomes to model inputs, a practice that may also be useful in recovery planning. The sensitivity analyses also provide insight into how the future trajectories would change if the elicited demographic rates are incorrect. Even when data are sparse, quantitative methods can often be used to produce rigorous and reproducible estimates of future status with quantifiable uncertainty.

ABSTRACT Wildlife populations are experiencing shifting dynamics due to climate and landscape change. Management policies that fail to account for non‐stationary dynamics may fail to achieve management objectives. We establish a framework for understanding optimal strategies for managing a theoretical harvested population under non‐stationarity. Building from harvest theory, we develop scenarios representing changes in population growth rate ( ) or carrying capacity ( ) and derive time‐dependent optimal harvest policies using stochastic dynamic programming. We then evaluate the cost of falsely assuming stationarity by comparing the outcomes of forward projections in which either the optimal policy or a stationary policy is applied. When declines over time, the stationary policy leads to an underharvest of the population, resulting in less harvest over the short term but leaving the population in a higher‐value state. When declines over time, the stationary policy leads to overharvest, resulting in greater harvest returns in the short term but leaving the population in a lower and potentially more vulnerable state. This work demonstrates the basic properties of time‐dependent harvest management and provides a framework for evaluating the many outstanding questions about optimal management strategies under climate change. Published 2021. This article is a U.S. Government work and is in the public domain in the USA.

Conspecific presence can indicate the location or quality of resources, and animals settling near conspecifics often gain fitness benefits. This can result in adaptive conspecific attraction during breeding habitat selection as demonstrated in numerous terrestrial, territorial birds. There is growing interest in using simulated conspecific social cues (e.g., decoys, broadcasted vocalizations) to manage bird distributions, yet it remains unclear when this approach is likely to succeed. We reviewed published studies to evaluate whether the strength of conspecific attraction in terrestrial birds is mediated by characteristics of species (life history traits), simulated cues (e.g., timing and duration), sites (e.g., quality), and how conspecific attraction was measured. We identified 31 experiments that simulated social cues and compared conspecific settlement between treatment and control sites. We then used phylogenetically controlled meta-regression to assess the impacts of 19 moderators on settlement. Nearly all species included in these experiments were migratory passerines, and social cues generally had a strong, positive influence on their settlement decisions, as the odds of site occupancy were 3.12x ( 95% CI: 0.81-11.69) greater in treatment sites relative to control sites. Within this group, conspecific attraction was evolutionarily conserved with >= 25.5% ( 95% CI: 5.1%-65.4%) of the variance in treatment effects explained by phylogenetic relatedness. However, we found no evidence that any covariates influenced the response to social cues, and we posit this stems from limited research specifically designed to identify the mechanisms mediating conspecific attraction. We therefore developed a research agenda that provides a framework for testing mechanistic hypotheses regarding how cue characteristics, species traits, and spatial contexts may mediate attraction to conspecifics. Evaluating these hypotheses will greatly advance the field by helping managers understand when, where, and why simulating social cues can be used to enhance populations of species that are of conservation concern.

ABSTRACT Population viability analyses are useful tools to predict abundance and extinction risk for imperiled species. In southeastern North America, the federally threatened gopher tortoise ( Gopherus polyphemus ) is a keystone species in the diverse and imperiled longleaf pine ( Pinus palustris ) ecosystem, and researchers have suggested that tortoise populations are declining and characterized by high extinction risk. We report results from a 30‐year demographic study of gopher tortoises in southern Alabama (1991–2020), where 3 populations have been stable and 3 others have declined. To better understand the demographic vital rates associated with stable and declining tortoise populations, we used a multi‐state hierarchical mark‐recapture model to estimate sex‐ and stage‐specific patterns of demographic vital rates at each population. We then built a predictive population model to project population dynamics and evaluate extinction risk in a population viability context. Population structure did not change significantly in stable populations, but juveniles became less abundant in declining populations over 30 years. Apparent survival varied by age, sex, and site; adults had higher survival than juveniles, but female survival was substantially lower in declining populations than in stable ones. Using simulations, we predicted that stable populations with high female survival would persist over the next 100 years but sites with lower female survival would decline, become male‐biased, and be at high risk of extirpation. Stable populations were most sensitive to changes in apparent survival of adult females. Because local populations varied greatly in vital rates, our analysis improves upon previous demographic models for northern populations of gopher tortoises by accounting for population‐level variation in demographic patterns and, counter to previous model predictions, suggests that small tortoise populations can persist when habitat is managed effectively. © 2021 The Wildlife Society.

Abstract The Arctic is undergoing rapid and accelerating change in response to global warming, altering biodiversity patterns, and ecosystem function across the region. For Arctic endemic species, our understanding of the consequences of such change remains limited. Spectacled eiders (Somateria fischeri), a large Arctic sea duck, use remote regions in the Bering Sea, Arctic Russia, and Alaska throughout the annual cycle making it difficult to conduct comprehensive surveys or demographic studies. Listed as Threatened under the U.S. Endangered Species Act, understanding the species response to climate change is critical for effective conservation policy and planning. Here, we developed an integrated population model to describe spectacled eider population dynamics using capture–mark–recapture, breeding population survey, nest survey, and environmental data collected between 1992 and 2014. Our intent was to estimate abundance, population growth, and demographic rates, and quantify how changes in the environment influenced population dynamics. Abundance of spectacled eiders breeding in western Alaska has increased since listing in 1993 and responded more strongly to annual variation in first‐year survival than adult survival or productivity. We found both adult survival and nest success were highest in years following intermediate sea ice conditions during the wintering period, and both demographic rates declined when sea ice conditions were above or below average. In recent years, sea ice extent has reached new record lows and has remained below average throughout the winter for multiple years in a row. Sea ice persistence is expected to further decline in the Bering Sea. Our results indicate spectacled eiders may be vulnerable to climate change and the increasingly variable sea ice conditions throughout their wintering range with potentially deleterious effects on population dynamics. Importantly, we identified that different demographic rates responded similarly to changes in sea ice conditions, emphasizing the need for integrated analyses to understand population dynamics.

Abstract Impacts of ecological mismatches should be most pronounced at points of the annual cycle when populations depend on a predictable, abundant, and aggregated food resource that changes in timing or distribution. The degree to which species specialize on a key prey item, therefore, should determine their sensitivity to mismatches. We evaluated the hypothesis that the effects of ecological mismatch during migratory stopover are mediated by a species’ foraging ecology by comparing two similar long‐distance migratory species that differ in their foraging strategies during stopover. We predicted that a specialist foraging strategy would make species more sensitive to effects of mismatch with a historically abundant prey, while an active, generalist foraging strategy should help buffer against changing local conditions. We estimated arrival times, start of mass gain, and rate of mass gain during spring stopover in Delaware Bay, USA. At this site, shorebirds feed on a temporally aggregated food resource (horseshoe crab Limulus polyphemus eggs), the timing of which is linked to water temperature; red knot (Calidris canutus rufa) specializes on these while the ruddy turnstone (Arenaria interpres) feeds more generally. We used a hierarchical nonlinear model to estimate the effect of mismatch between shorebird arrivals and timing of crab spawning on the timing and rate of mass gain over 22 yr. In years with cooler water temperature, crabs spawned later, which was associated with later and faster mass gain for the knots. Turnstones exhibited less inter‐annual variation in the timing and rate of mass gain than knots, and we found no relationship between mass gain dynamics and the availability of horseshoe crab eggs for this generalist species. Long‐distance migrants rely on predictable resources en route and even when these linkages are simple and predictable, populations can be vulnerable to change; these results suggest that generalist foraging strategies may buffer migratory species against phenological mismatch. We provide a framework to evaluate population responses to changes in prey phenology at sites vulnerable to climatic change.

ABSTRACT All ecological measurements are subject to error; the effects of missed detection (false negatives) are well known, but the effects of mistaken detection (false positives) are less understood. Long-term capture–recapture datasets provide valuable ecological insights and baselines for conservation and management, but where such studies rely on noninvasive re-encounters, such as field-readable color bands, there is the potential to accumulate detection errors as the length of the study and number of tags deployed increases. We investigated the prevalence and effects of misreads in a 10-yr dataset of Red Knots (Calidris canutus rufa) marked with field-readable leg flags in Delaware, USA. We quantified the effects of misreads on survival estimation via a simulation study and evaluated whether removal of individuals only reported once in a year (potential misreads) influenced survival estimation from both simulated datasets and our case study data. We found overall apparent error rates of 0.31% (minimum) to 6.6% (maximum). Observer-specific error rates and the variation among observers both decreased with the number of flags an observer recorded. Our simulation study showed that misreads lead to spurious negative trends in survival over time, particularly for long-term studies. Removing all records in which a flag was only recorded once in a sampling occasion reduced bias and eliminated spurious negative trends in survival but also reduced precision in survival estimates. Without data filtering, we found a slight decrease in Red Knot annual survival probability from 2008 to 2018 (β = -0.043 ± 0.03), but removing all single-observation records resulted in no apparent trend (β = -0.0074 ± 0.02). Spurious trends in demographic rates could influence inference about population trajectories and resultant conservation decision-making. Data filtering could eliminate errors, but researchers should carefully consider the tradeoff between precision obtained by larger sample sizes and potential bias due to misreads in their data.

Species that provide intensive parental care could suffer fitness costs associated with conspecific brood parasitism. Here we evaluate the effect of conspecific brood parasitism on apparent annual survival probability of female Prothonotary Warblers Protonotaria citrea using a multistate model with imperfect state assignment analysed in a hierarchical Bayesian framework. We found no difference in annual survival probability between host and non-host females. These findings agree with previous work in that there seems to be little apparent cost of conspecific brood parasitism to female Warblers in this system.

Thirty years of research has made carotenoid coloration a textbook example of an honest signal of individual quality, but tests of this idea are surprisingly inconsistent. Here, to investigate sources of this heterogeneity, we perform meta-analyses of published studies on the relationship between carotenoid-based feather coloration and measures of individual quality. To create color displays, animals use either carotenoids unchanged from dietary components or carotenoids that they biochemically convert before deposition. We hypothesize that converted carotenoids better reflect individual quality because of the physiological links between cellular function and carotenoid metabolism. We show that feather coloration is an honest signal of some, but not all, measures of quality. Where these relationships exist, we show that converted, but not dietary, carotenoid coloration drives the relationship. Our results have broad implications for understanding the evolutionary role of carotenoid coloration and the physiological mechanisms that maintain signal honesty of animal ornamental traits.

Conspecific brood parasitism (CBP), although prevalent in some avian taxa, is easily overlooked when it occurs in low frequencies, and therefore the ecology of this behavior has only occasionally been described in passerines. We describe the occurrence of CBP in a population of Prothonotary Warblers (Protonotaria citrea) breeding in nest boxes, demonstrate associated fitness costs, and investigate parasite strategy. We genotyped individuals at 6 microsatellite loci and used Cervus software to determine log-likelihood of maternity (LOD scores) for offspring and social mothers. We set critical cutoff LOD scores at 95% confidence for exclusion of the social mother and assignment of a parasite mother from the breeding population. Of 805 nestlings (233 family groups during 2009-2013), we found that 12.7% had genotypes that were incompatible with their social mother. Females with unrelated nestlings (hosts) fledged fewer biological offspring within the host year than nonhost females despite fledging more total offspring, but being a host was not significantly associated with total reproductive success over 5 yr of breeding. We were able to identify only similar to 30% of parasite females, which suggests that the majority of parasites may be floaters (i.e. non-nesters) in the population or nesting in nearby natural cavities. We found no evidence of host selection based on host age, arrival at the breeding site, or nest-box productivity in the previous year. This opportunistic behavior is likely facilitated by the nesting ecology of this population, in that nest sites are limited, conspicuous, and relatively dense. Future studies investigating CBP in populations using natural cavities can help elucidate the drivers of this behavior.