About
36
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Introduction
My research makes use of field, lab, and remotely sensed data integrated with rigorous quantitative tools to 1) address fundamental questions about migration biology, 2) understand how and why migration is changing and migratory species are declining, and 3) develop tools for the inclusion of stopover and airspace habitats into conservation and management efforts for migratory species.
Publications
Publications (36)
Management of waterfowl that migrate seasonally across North America occurs within four flyways that were delineated in the early 1900s to include the annual movements of populations. Movements may have changed over the past century since administrative flyways were established, and may do so while management plans are in use, so information about...
As wind energy rapidly expands worldwide, information to minimize impacts of this development on biodiversity is urgently needed. Here we demonstrate how data collected by weather radar networks can inform placement and operation of wind facilities to reduce collisions and minimize habitat‐related impacts on nocturnally migrating birds. We found ov...
Refueling performance is the primary currency of a successful migration as birds must maintain energy stores to achieve an optimal travel schedule. Migrating birds can anticipate heightened energy demand, not to mention increased uncertainty that energy demands will be satisfied, especially within an urbanizing landscape following long-distance fli...
Migrating birds contend with dynamic wind conditions that ultimately influence most aspects of their migration, from broad-scale movements to individual decisions about where to rest and refuel. We used weather surveillance radar data to measure spring stopover distributions of northward migrating birds along the northern Gulf of Mexico coast and f...
en An understanding of the full annual cycle distributions of bird populations is a prerequisite to elucidating the drivers of differing trends among breeding populations. In the United States, Black-crowned Night-Herons (Nycticorax nycticorax) are listed as threatened or endangered in some states where they breed, but populations are stable in oth...
Animal movements, especially avian migration, can be a mechanism for the large-scale dispersal and geographic range expansion of parasites. The host-parasite relationships among birds during migration have yet to be fully explored. We characterized the haemosporidian parasite lineages in passerines during spring migration on the Texas coast of the...
Migrating birds require en route habitats to rest and refuel. Yet, habitat use has never been integrated with passage to understand the factors that determine where and when birds stopover during spring and autumn migration. Here, we introduce the stopover‐to‐passage ratio (SPR), the percentage of passage migrants that stop in an area, and use 8 ye...
Migrations of diverse wildlife species often converge in space and time, with their journeys shaped by similar forces (i.e. geographic barriers and seasonal resources and conditions); we term this ‘co‐migration’. Recent studies have illuminated multi‐speciesmigrations by land and sea including the simultaneous movements of numerous insects, birds,...
The dynamic weather conditions that migrating birds experience during flight likely influence where they stop to rest and refuel, particularly after navigating inhospitable terrain or large water bodies, but effects of weather on stopover patterns remain poorly studied. We examined the influence of broad-scale weather conditions encountered by noct...
The distributions of birds during migratory stopovers are influenced by a hierarchy of factors. For example, in temperate regions, migrants are concentrated near areas of bright artificial light at night (ALAN) and also the coastlines of large water bodies at broad spatial scales. However, less is known about what drives broad-scale stopover distri...
Quantifying the timing and intensity of migratory movements is imperative for understanding impacts of changing landscapes and climates on migratory bird populations. Billions of birds migrate in the Western Hemisphere, but accurately estimating the population size of one migratory species, let alone hundreds, presents numerous obstacles. Here, we...
The strength of migratory connectivity is a measure of the cohesion of populations among phases of the annual cycle, including breeding, migration, and wintering. Many Nearctic‐Neotropical species have strong migratory connectivity between breeding and wintering phases of the annual cycle. It is less clear if this strength persists during migration...
Technological advancements have spurred rapid growth in the study of migratory connectivity, the linkage of individuals and populations between seasons of the annual cycle. The strength of migratory connectivity is a measure of the co-occurrence of populations throughout the annual cycle and can be represented by a correlation of the distances betw...
Habitats around the Gulf of Mexico (GOM) provide critical resources for Nearctic-Neotropical migratory landbirds, the majority of which travel across or around the GOM every spring and fall as they migrate between temperate breeding grounds in North America and tropical wintering grounds in the Caribbean and Central and South America. At the same t...
Climate change is a serious challenge faced by all plant and animal species. Climate change vulnerability assessments (CCVAs) are one method to assess risk and are increasingly used as a tool to inform management plans. Migratory animals move across regions and continents during their annual cycles where they are exposed to diverse climatic conditi...
Migratory birds have the potential to transport exotic vectors and pathogens of human and animal health importance across
vast distances. We systematically examined birds that recently migrated to the United States from the Neotropics for ticks.
We screened both ticks and birds for tick-borne pathogens, including Rickettsia species and Borrelia bur...
For vertebrates, annual cycles are organized into a series of breeding and non-breeding periods that vary in duration and location but are inextricably linked biologically. Here, we show that our understanding of the fundamental ecology of four vertebrate classes has been limited by a severe breeding season research bias and that studies of individ...
Migratory songbirds are advancing their arrival to breeding areas in response to climatic warming at temperate latitudes. Less is understood about the impacts of climate changes outside the breeding period. Every spring, millions of migrating songbirds that overwinter in the Caribbean and Central and South America stop to rest and
refuel in the fir...
1.A major aim of bird ringing is to provide information about the migration and movements of bird populations. However, in comparison with demographic studies, little research has been devoted to improving quantitative inferences through large-scale spatial analyses. This represents a serious knowledge gap because robust information on geographic l...
Predicting how migratory animals respond to changing climatic conditions requires knowledge of how climatic events affect each phase of the annual cycle and how those effects carry-over to subsequent phases. We utilized a 17-year migration dataset to examine how El Niño-Southern Oscillation climatic events in geographically different regions of the...
Understanding the biology and conducting effective conservation of migratory species requires an understanding of migratory connectivity – the geographic linkages of populations between stages of the annual cycle. Unfortunately, for most species, we are lacking such information. The North American Bird Banding Laboratory (BBL) houses an extensive d...
Long-distance migration is characterized by
periods of flight, when energy stores are consumed, and
periods of stopover, when energy stores are replenished.
The duration of the migratory period is largely determined
by time spent at stopover sites. The time constraints
imposed on spring migrants should act to minimize the
time spent on migration, y...
The behavior of long-distance migrants during stopover is constrained by the need to quickly and safely replenish energetic reserves. Replenishing fuel stores at stopover sites requires adjusting to unfamiliar landscapes with little to no information about the distribution of resources. Despite their critical importance to the success of songbird m...
Climate change is a serious challenge faced by all flora and fauna on earth. Climate vulnerability
analyses are one method to assess risk and are increasingly used as a tool to inform management plans.
Ideally, risk should be assessed throughout an animal’s entire annual cycle, but migratory animals move
across vast regions and can be difficult to...
Movement patterns during songbird migration remain poorly understood despite their expected fitness consequences in terms of survival, energetic condition and timing of migration that will carry over to subsequent phases of the annual cycle. We took an experimental approach to test hypotheses regarding the influence of habitat, energetic condition,...
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We monitored nesting attempts of White-throated (Turdus assimilis) and Clay-colored thrushes (T. grayi) over 4 years in southern Costa Rica to compare nest success in recently abandoned coffee (Coffea spp.) plantations, pasture, and along roads. Daily mortality rates of Clay-colored Thrush nests were lower in pasture (0.054 ± 0.014) than abandoned...
Most work on the effects of land-cover change on tropical birds has focused on forest-interior birds because these species are assumed to be the most severely affected by forest loss. However, even species that use human-altered habitat types may be severely affected by forest loss. White-throated Robins (Turdus assimilis) frequently nest in coffee...
We used radiotelemetry to study behavior of White-throated Robins (Turdus assimilis) during the postfledging dependent period. The study was conducted in a mixed agricultural and forested landscape in southern Costa Rica from March through August of 2001 and 2002. A transmitter was attached to one fledgling per brood (n = 53). Each bird was located...
We used radiotelemetry to study behavior of White-throated Robins (Turdus assimilis) during the postfledging dependent period. The study was conducted in a mixed agricultural and forested landscape in southern Costa Rica from March through August of 2001 and 2002. A transmitter was attached to one fledgling per brood (n = 53). Each bird was located...
We used radiotelemetry to study behavior of White-throated Robins (Turdus assimilis) during the postfledging dependent period. The study was conducted in a mixed agricultural and forested landscape in southern Costa Rica from March through August of 2001 and 2002. A transmitter was attached to one fledgling per brood (n = 53). Each bird was located...
We determined if the daily mortality rate (dmr) for artificial clutches of Zebra Finch (Taeniopy, gia guttata) and Japanese Quail (Coturnix japonica) eggs matched the dmr of real clutches of the White-throated Robin (Turdus assimilis), in Costa Rica. In 2002 we found and monitored robin nests until fledging or failure After each nesting attempt end...
Projects
Projects (3)
The Migratory Connectivity Project was created to advance the conservation and understanding of migratory animals.
Project objectives
1) To discover the geographic linkages of individuals, populations, and species throughout their lives (migratory connectivity).
2) To advance science by encouraging the development and use of the technology used to track animals.
3) To use this information to protect species by working with governmental and non-governmental partners to integrate full-life cycle biology into conservation planning processes.
4) To connect people across cultures by educating local and international communities about the migratory animals that they share.
Over two-thirds of all landbirds and over half of the migratory species that breed in temperate North America move long distances to nonbreeding areas in Mexico, Central and South America and Caribbean islands. Movement across the Gulf of Mexico (GOM) is a conspicuous, energetically demanding feature of this bird migration system. Habitats along the northern coast of the GOM provide the last possible stopover before fall migrants make a nonstop flight, and the first possible landfall for birds returning north in spring. Migrant-habitat relations are critical when birds must cross this barrier, yet the availability of suitable habitat for birds is often at odds with rapid growth and development in coastal landscapes. Long term data reveal declines among many migratory bird populations, and events associated with migration, including the quality and amount of stopover habitat, are implicated in this decline.Therefore, we are working to better understand migration and stopover ecology of songbirds along the northern GOM.
