Kenneth V. Rosenberg

Citizen Science: A Developing Tool for Expanding Science Knowledge and Scientific Literacy

Citizen science enlists the public in collecting large quantities of data across an array of habitats and locations over long spans of time. Citizen science projects have been remarkably successful in advancing scientific knowledge, and contributions from citizen scientists now provide a vast quantity of data about species occurrence and distribution around the world. Most citizen science projects also strive to help participants learn about the organisms they are observing and to experience the process by which scientific investigations are conducted. Developing and implementing public data-collection projects that yield both scientific and educational outcomes requires significant effort. This article describes the model for building and operating citizen science projects that has evolved at the Cornell Lab of Ornithology over the past two decades. We hope that our model will inform the fields of biodiversity monitoring, biological research, and science education while providing a window into the culture of citizen science.

Adverse effects of acid rain on the distribution of the Wood Thrush Hylocichla mustelina in North America

Research into population declines of North American bird species has mainly focused on the fragmentation of habitat on the breeding or wintering grounds [Robinson, S. K., Thompson, F. R., Donovan, T. M., Whitehead, D. R. & Faaborg, J. (1995) Science 267, 1987–1990]. In contrast, research into declines of European species has mainly focused on intensification of agriculture [Donald, P. F., Green, R. E. & Heath, M. F. (2001) Proc. R. Soc. London Ser. B 268, 25–29] and the role played by the atmospheric deposition of pollutants, in particular, acid rain [Graveland, J. (1998) Environ. Rev. 6, 41–54]. However, despite widespread unexplained declines of bird populations in regions of heavy wet acid ion deposition [Sauer, J. R., Hines, J. E. & Fallon, J. (2001) The North American Breeding Bird Survey Results and Analysis 1966–2000 (Patuxent Wildlife Research Center, Laurel, MD)], no North American studies have presented evidence linking such widespread terrestrial bird declines to acid rain. To address the question of the role played by acid rain in population declines of eastern North American songbird species, we combine data from several sources. We use a multiple logistic regression model to test for adverse effects of acid rain on the Wood Thrush, while controlling for regional abundance, landscape-level habitat fragmentation, elevation, soil pH, and vegetation. We show a strong, highly significant, negative effect of acid rain on the predicted probability of breeding by this species, and interactions with elevation, low pH soils, and habitat fragmentation that worsen these negative effects. Our results suggest an important role for acid rain in recent declines of some birds breeding in the eastern United States, particularly in high elevation zones with low pH soils, and show the need to consider other large-scale influences, in addition to habitat fragmentation, when addressing bird population declines.

Priority research needs for the conservation of Neotropical migrant landbirds

Abstract Partners in Flight (PIF) is a consortium of professional and volunteer scientists and educators that promotes the conservation of landbird species. Central to the PIF conservation effort is the development of Bird Conservation Plans specific to each physiographic region of the United States. Without a coordinated prioritization of research needs, land managers, researchers, and funding agencies seeking to conserve landbirds lack direction. To address this issue, we (the Research Working Group of Partners in Flight) identified research priorities that have emerged recently as a result of Bird Conservation Plan development. Research priorities for the coming decade focus on habitat, specifically the identification of high-quality habitats and landscapes for breeding, migration, and wintering. Identification of the scale of breeding and natal dispersal and describing linkages between wintering and breeding populations are also research priorities for the coming decade. A summary of research priorities for each of the PIF regions (Northeast, Midwest, West, and South) is also provided. Specific research needs associated with priority species and habitats in each physiographic area can be accessed in a searchable database: http://www.partnersinflight.org/pifneeds/searchform.cfm.

STATUS AND CONSERVATION PRIORITIES OF GOLDEN-WINGED WARBLER (VERMIVORA CHRYSOPTERA) IN NORTH AMERICA

department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, Tennessee 37996, USA; 2School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, USA; Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, New York 14850, USA; 4 U.S. Fish and Wildlife Service, Region 3, Nongame Migratory Bird Office, Fort Snelling, Minnesota 55111, USA; ^Department of Biology, Ithaca College, Ithaca, New York 14850, USA; department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio 45221, USA; and 7Conservation Science Program, Cornell Lab of Ornithology, Ithaca, New York 14850, USA

Irruptive migration of common redpolls

We do not know whether the movements of irruptive migrants are fundamentally different from more conventional migration of birds to their wintering areas because irruptive migration has never been thoroughly described for any species on a continent-wide scale. We use data from a citizen-based monitoring program, Project FeederWatch, to describe the patterns of movements of redpolls (principally Carduelis flammea) across North America in 1993-1994, the winter of a major irruptive migration. Although redpolls moved into new areas during this irruptive migration, the normal wintering range was not completely abandoned. In fact, redpolls were more prevalent in the southern part of their normal wintering range in an irruption year than was typical in non-irruption years. There also was no indication that the majority of the North American population of redpolls moved continuously through the winter: although redpolls peaked in prevalence at different times across the continent, their spring departure was relatively synchronous across the entire continent Group sizes were typically smaller the later redpolls arrived in a region, also suggesting that the entire redpoll population did not move continuously. In contrast to a non-irruptive migrant, the American Tree Sparrow (Spizella arborea), redpolls arrived at feeders in a given region later but reached peak densities more quickly. Our results suggest that the irruptive migration of redpolls is more allied to conventional winter migration than to nomadism.

Epinecrophylla, a new genus of antwrens (Aves: Passeriformes: Thamnophilidae)

ABSTRACT We offer a new generic name for the stipple-throated assemblage of antwrens (Thamnophilidae) currently placed in the genus Myrmotherula. Molecular studies demonstrated that Myrmotherula is polyphyletic, with the stippled-throated group forming a clade that is not sister to any other currently recognized Myrmotherula species. The stipple-throated assemblage is distinguished morphologically by at least one sex having a black throat stippled white or buffy white combined with a comparatively long, unmarked tail, although three populations considered subspecies have lost one of these characters. The distinct evolution of this assemblage is supported by diagnostic behavioral characters derived from foraging behaviors, vocal repertoires, and nest architecture.

Fall Migration of the Veery (Catharus fuscescens) in Northern Colombia: Determining the Energetic Importance of a Stopover Site

ABSTRACT. Migration is a highly energy-demanding process, and migratory birds store energy at stopover sites along their migration routes to meet these demands. The Veery (Catharus fuscescens) performs one of the longest migrations of all Neotropical migratory landbirds, yet the stopover sites that it uses and their relative importance to migratory success are poorly known. We studied the Veery during two fall migrations (2009 and 2010) in northern Colombia, where we hypothesized that birds would replenish energy reserves after crossing the Caribbean Sea to fuel flights toward their wintering grounds. To determine the relative energetic importance of our study site, we combined estimates of fuel deposition rates, stopover durations, and flight ranges to estimate the percentage of the total migratory distance that could be covered following a stopover. Veeries arrived at our study site with low energy reserves, and recaptured birds increased their body mass at a mean rate of 3.6% of lean body mass day-1 over an average of 9 days. At departure, birds carried energy reserves equivalent to 34.5% of lean body mass, giving rise to a maximum potential flight range of 2,200 km, thereby allowing them to cover ≤30% of the total fall migration distance, depending on how reserves are used. By showing how a stopover site is used in energetic terms, we highlight the importance of a site in northern Colombia to long-distance Neartic—Neotropic migrants and also introduce a method that contributes to the prioritization of stopover sites across regions and species.

Understanding the Risk to Neotropical Migrant Bird Species of Multiple Human-Caused Stressors: Elucidating Processes Behind the Patterns.

Ubiquitous human-caused changes to the environment act as multiple stressors for organisms in the wild, and the effects of these stressors may be synergistic, rather than merely additive, with unexpected results. However, understanding how focal organisms respond to these stressors is crucial for conservation planning for these species. We propose a paradigm that alternates extensive, broadscale data collection by volunteer collaborators to document patterns of response, with intensive fine-scale studies by professional researchers, to elucidate the processes underlying these patterns. We demonstrate this technique, building on our existing work linking patterns of population declines in the Wood Thrush ( Hylocichla mustelina) to synergistic effects of acid rain and habitat fragmentation. To better understand the processes behind these patterns, we use a simple protocol to explore linkages between acid rain, leaching of calcium from the soil, and declines in the abundance of calcium-rich invertebrate prey species, which may be necessary for successful breeding by this thrush. We sampled at 40 study sites across New York that were chosen based on estimated acid deposition and soil properties. Our results show that the calcium content of the soils sampled is proportional to the soil pH, that the abundance of calcium-rich invertebrate prey tracks soil properties, and that the presence of a breeding Wood Thrush was correctly predicted in >70% of study sites by the biomass of calcium-rich prey, and in particular, the biomass of myriapods (Diplopoda). We show that a simple repeatable protocol, suitable for use by volunteers across broad geographic extents and ranges of habitat fragmentation, can help us understand the reactions of some forest birds to acid rain in combination with habitat fragmentation. We detail the development of this protocol for volunteers in the Birds in Forested Landscapes project, and describe future plans.

Fuel loads acquired at a stopover site influence the pace of intercontinental migration in a boreal songbird

Long-distance migratory organisms are under strong selection to migrate quickly. Stopovers demand more time than flying and are used by individuals to refuel during migration, but the effect of fuel loads (fat) acquired at stopover sites on the subsequent pace of migration has not been quantified. We studied stopover behaviour of Grey-cheeked Thrush (Catharus minimus) at a site in northern Colombia and then tracked their migration using an intercontinental radio-telemetry array. Tracking confirmed long-distance flights of more than 3000 km, highlighting the key importance of a single stopover site to the migration strategy of this species. Our results suggest that these songbirds behave as time-minimizers as predicted by optimal migration theory, and that fuel loads acquired at this South American stopover site, together with departure date, carry-over to influence the pace of migration, contributing to differences in travel time of up to 30 days in birds subsequently detected in the U. S. and Canada. Such variation in the pace of migration arising from a single stopover site, likely has important fitness consequences and suggests that identifying important fuelling sites will be essential to effectively conserve migratory species.

Seasonal variation in stopover site use: Catharus thrushes and vireos in northern Colombia

AbstractMigratory routes and stopover sites used by migrant landbirds may vary among seasons and years. Understanding the degree of such variation is an important aspect of migrant ecology, especially in South America, where routes and sites are not well known. We studied stopover site use by two Vireo species and three Catharus species in the Sierra Nevada de Santa Marta in northern Colombia during a two-year period. We used capture totals corrected for mist-net effort and density estimates derived from variable distance transect observations performed at sites located at three different altitudes and thus habitats to describe variation in stopover site use. Four of the five study species showed significant seasonal variation in terms of presence, such that ecologically similar species were present during opposite migration periods; for example, Vireo flavoviridis was an autumn migrant, while Vireo olivaceus was commonest in spring. A similar pattern was observed for Catharus fuscescens and Catharus minimus. We detected differences in density with habitat/altitude, with C. minimus and Catharus ustulatus most abundant in pre-montane forest, while C. fuscescens abundance peaked in lowland forest. At the same altitude, Catharus species were more abundant in pre-montane forest than in shade coffee plantations. The abundance of C. ustulatus varied markedly between years during autumn migration, potentially in association with changes in the prevailing wind conditions. The temporal and spatial variation in stopover site use described here provides important insights into migratory strategies for Neotropical migrants within northern South America, and also regarding the multiple factors that may have shaped these strategies.ZusammenfassungJahreszeitliche Variation in der Nutzung von Rastgebieten:Catharus-Drosseln und Vireos im nördlichen Kolumbien Vogelzugrouten und verfügbare Rastgebiete können saisonal und auch zwischen den Jahren variieren. Ein besseres Verständnis des Ausmaßes dieser Variation ist ein wichtiger Aspekt der Vogelzugökologie, besonders in Südamerika, wo Zugrouten und Rastgebiete oft nicht bekannt sind. Wir haben Rastgebiete von zwei Vireo- und drei Catharus-Arten in der Sierra Nevada de Santa Marta im nördlichen Kolumbien während zwei Jahren untersucht. Zur Beschreibung der Variation der Nutzung der Rastgebiete verwendeten wir die Gesamtzahl gefangener Vögel korrigiert um den Fangaufwand und Dichteschätzungen auf Grundlage von verschiedenen Distanz-Transekt Zählungen in drei verschiedenen Höhenlagen und verschieden Habitaten. Vier der fünf untersuchten Arten zeigten signifikante jahreszeitliche Variation in ihrer Anwesenheit. Ökologisch ähnliche Arten waren in den jeweils gegenläufigen Zugperioden anwesend. So war V. flavoviridis ein Herbstzieher, während V. olivaceus im Frühjahr häufiger war. Ein ähnliches Muster konnte zwischen C. fuscescens and C. minimus beobachtet werden. Wir beschreiben Unterschiede in der Dichtheit innerhalb der Habitate und Höhenlagen. C. minimus und C. ustulatus waren häufiger im submontanem Wald anzutreffen während C. fuscescens häufiger im Tieflandregenwald vorkam. Auf der gleichen Höhenlage war Catharus häufiger in submontanem Wald als in schattigen Kaffeeplantagen anzutreffen. Die Abundanz von C. ustulatus variierte während des Herbstzuges deutlich zwischen den Jahren, und ist möglicherweise assoziiert mit Veränderungen in den vorherrschenden Windkonditionen. Die zeitliche und räumliche Variation in der Nutzung von Rastgebieten liefert wichtige Erkenntnisse in der Zugstrategie neotropischer Zugvögel im nördlichen Südamerika und suggeriert, dass multiple Faktoren derartige Strategien gefördert haben können.