Kristen Covino - Academia.edu (original) (raw)

Papers by Kristen Covino

Journal of Animal Ecology

The timing of avian migration has evolved to exploit critical seasonal resources, yet plasticity ... more The timing of avian migration has evolved to exploit critical seasonal resources, yet plasticity within phenological responses may allow adjustments to interannual resource phenology. The diversity of migratory species and changes in underlying resources in response to climate change make it challenging to generalize these relationships. We use bird banding records during spring and fall migration from across North America to examine macroscale phenological responses to interannual fluctuations in temperature and long‐term annual trends in phenology. In total, we examine 19 species of North American wood warblers (family Parulidae), summarizing migration timing from 2,826,588 banded birds from 1961 to 2018 across 46 sites during spring and 124 sites during fall. During spring, warmer spring temperatures at banding locations translated to earlier median passage dates for 16 of 19 species, with an average 0.65‐day advancement in median passage for every 1°C increase in temperature, ra...

The Auk, Oct 26, 2022

In response to a growing need to foster ethical behavior within scientific societies, the America... more In response to a growing need to foster ethical behavior within scientific societies, the American Ornithological Society’s (AOS) professional ethics committee conducted a survey of members in spring 2021 to identify the primary challenges and ethical conduct concerns. The survey indicated that the AOS has a strong culture of professional ethics and highlighted areas needing improvement. Participants identified discrimination and lack of inclusivity (44%), scientific fraud and abuse in data and publications (35%), and sexual harassment (31%) as the highest potential risks for unethical behavior in our organization. Moreover, approximately one-third of respondents (34%) had personally witnessed or experienced unethical behavior as an AOS member. A smaller proportion (16%) felt pressure to compromise their work standards in ornithology. These findings are likely representative of broader patterns that professional, scientific societies face as they seek to provide safe, welcoming, and thoughtful environments for researchers to share their work, gain valuable feedback, and develop collaborations. The survey results also create a framework for workshops, training opportunities, and disseminating information within the AOS and, ideally, with the broader, international community of ornithologists.

Journal of Avian Biology, Jan 12, 2022

Ornithology

Journal of Avian Biology, 2014

Behavioral decisions made by migrating songbirds may depend on a variety of biotic and abiotic fa... more Behavioral decisions made by migrating songbirds may depend on a variety of biotic and abiotic factors. To investigate which factors most infl uence songbird behavior on stopover, we related departure and directional decisions of captive birds released at the capture site to a variety of factors including, weather, date, energetic condition, age, sex, and species. We captured spring migrants during the day, released them after sunset, and visually assessed whether they departed the study site and if so, in which direction. Departure was strongly infl uenced by wind direction and energetic condition, especially fat stores. Th e proportion of birds departing increased as the season progressed. Directional decisions were also strongly infl uenced by energetic condition, particularly fat stores and plasma triglyceride levels. Wind direction also infl uenced the direction in which birds made migratory fl ights. While energetic condition, stage of migration, and weather seem to be important proximate determinants in departure and directional decisions, habitat availability and other factors may also need to be considered.

The Wilson Journal of Ornithology

Animal Migration, 2015

Nocturnally migrating birds experience loss of sleep during the migratory period especially when ... more Nocturnally migrating birds experience loss of sleep during the migratory period especially when undertaking long, non-stop flights. We report a field observation of daytime sleeping behavior in a Black-andwhite Warbler (Mniotilta varia) during spring migration. It is likely that this individual was compensating from sleep loss experienced during a trans-Gulf of Mexico flight. Only a few observations of daytime sleeping behavior have been reported in free-living migrants and all have been associated with long-distance flights in relation to ecological barriers.

General and comparative endocrinology, Jan 24, 2015

Preparation for breeding may overlap extensively with vernal migration in long-distance migratory... more Preparation for breeding may overlap extensively with vernal migration in long-distance migratory songbirds. Testosterone plays a central role in mediating this transition into breeding condition by facilitating changes to physiology and behavior. While changes in testosterone levels are well studied in captive migrants, these changes are less well known in free-living birds. We examined testosterone levels in free-living Nearctic-Neotropical migrants of three species during their vernal migration. Testosterone levels increased during the migratory period in males of all three species but significantly so in only two. Testosterone levels in females remained the same throughout their migration. Our results support the extensive overlap between vernal migration and breeding preparation in male songbirds. The pattern of testosterone changes during vernal migration is far from clear in females.

13 Introduction 13 Materials and Methods 17 Study Species 17 Capture and Sampling 18

Plumage ornamentation in birds serves critical inter- and intra-sexual signaling functions. While... more Plumage ornamentation in birds serves critical inter- and intra-sexual signaling functions. While carotenoid-based plumage colouration is often viewed as a classic condition-dependent sexually selected trait, plumage colouration can be influenced by a wide array of both intrinsic and extrinsic factors. Understanding the mechanisms underlying variation in colouration is especially important for species where the signaling function of ornamental traits is complex or the literature conflicting. Here, we examined variation in the yellow/orange tail feathers of American redstarts (Setophaga ruticilla) passing through two migratory stopover sites in eastern North America during both spring and fall migration to assess the role of geographic variation and seasonality in influencing feather colouration. In addition, we investigated whether diet during moult (inferred via stable isotope analysis of feather δ15N and δ13C) influenced plumage colouration. Our findings indicate that geographic v...

Ornithological Applications

The understanding that motherhood impacts career paths is so pervasive among early-career scienti... more The understanding that motherhood impacts career paths is so pervasive among early-career scientists that some feel they must choose parenthood or a career. The penalties associated with motherhood can contribute to the “leaky pipeline,” which equates to the high attrition rate of women due to social, economical, or temporal factors as they proceed through their career and exacerbates persistent gender gaps at mid- and late-career stages. Here, we review the literature and summarize common challenges faced by ornithologist mothers and nonbinary parents, and we adopt a full lifecycle approach to recommend evidence-based strategies for overcoming those challenges. The American Ornithological Society (AOS) is well positioned to support and celebrate women and nonbinary ornithologists who choose parenthood, and we highlight progress made by the AOS to improve gender diversity, equity, and inclusion within the Society. For example, AOS caregiver grants allow more parents to attend and pa...

Avian Conservation and Ecology

Hormones and behavior, 2018

In seasonally migratory species, the overlap between the migratory and breeding life history stag... more In seasonally migratory species, the overlap between the migratory and breeding life history stages is a balance between the physiological and behavioral requirements of each stage. Previous studies investigating the degree to which songbirds prepare for breeding during spring migration have focused on either circulating hormone levels or direct measures of gonadal recrudescence. In this study, we evaluated the phenology of breeding preparation in a long-distance migratory songbird, the Swainson's Thrush (Catharus ustulatus), by assessing hypothalamic-pituitary-gonadal (HPG) axis sensitivity with gonadotropin-releasing hormone (GnRH) bioassays throughout the migratory period. During spring migration both males and females had a significant response to GnRH injections as reflected in elevated testosterone levels. The magnitude of response to GnRH injections, R, in females stayed consistent throughout spring migration; however, R in males increased as the migratory season progress...

The Auk

The Auk, Feb 20, 2020

The availability of detailed information that encompasses the geographic range of a species, span... more The availability of detailed information that encompasses the geographic range of a species, spans a long-term temporal range, and yields individual information (e.g., age and sex), is a principle challenge in ecology. To this end, the North American Bird Banding Laboratory maintains a unique and underutilized dataset that can be used to address core questions of phenological change in migratory birds. We used records from 1966 to 2015 to quantify how the timing of migration has shifted in a long-distance migrant, the Black-throated Blue Warbler (Setophaga caerulescens). Additionally, we examined age and sex differences in the timing of migratory movements. We observed that early spring migrants passed through sites ~1.1 days earlier per decade and the peak of spring migration also occurred earlier over the 50 yr of this study. Additionally, phenological change was more rapid with increasing latitude during peak spring migratory periods. During fall, the peak of migration stayed consistent across the 50 yr studied, but the migratory season showed protraction overall. During spring, males consistently migrated earlier than females and adults migrated earlier than young individuals. During fall, there was no difference in timing between males and females, but young birds migrated earlier than adults. Additionally, migration proceeded faster in spring compared with the fall. This study reveals differential strategies in migrant timing, across seasons, age groups, and by sex, and shows that en route adjustments across latitude may account for changes in migrant timing. This basic information about such a fundamental ecological process is crucial to our understanding of migration and we must utilize these unique data to appreciate critical shifts at relevant scales of migration.

Frontiers in zoology, Jan 15, 2006

Geometric morphometric methods of capturing information about curves or outlines of organismal st... more Geometric morphometric methods of capturing information about curves or outlines of organismal structures may be used in conjunction with canonical variates analysis (CVA) to assign specimens to groups or populations based on their shapes. This methodological paper examines approaches to optimizing the classification of specimens based on their outlines. This study examines the performance of four approaches to the mathematical representation of outlines and two different approaches to curve measurement as applied to a collection of feather outlines. A new approach to the dimension reduction necessary to carry out a CVA on this type of outline data with modest sample sizes is also presented, and its performance is compared to two other approaches to dimension reduction. Two semi-landmark-based methods, bending energy alignment and perpendicular projection, are shown to produce roughly equal rates of classification, as do elliptical Fourier methods and the extended eigenshape method ...