Non-breeding Ecology Research Articles

Non-breeding ecology of a Neotropical-Nearctic migrant, the Common Nighthawk ( Chordeiles minor ): habitat, activity patterns, molt, and migration

Non-breeding ecology of a Neotropical-Nearctic migrant, the Common Nighthawk ( Chordeiles minor ): habitat, activity patterns, molt, and migration

Eastern Whip-poor-wills have larger nonbreeding home ranges in areas with more agriculture and forest fragmentation

AbstractMigratory bird populations can be limited by events in disparate parts of the world. Birds wintering in tropical regions are facing rapid habitat loss, climate change, and intensive agricultural regimes, potentially contributing to population declines. However, an understanding of basic nonbreeding ecology of species, such as habitat and space use, is critical for determining if this is the case. Populations of the nocturnal/crepuscular Eastern Whip-poor-will (Antrostomus vociferus) have declined by 70% since the 1960’s, yet data on the species are sparse outside of the breeding season. We extracted data from 41 archival GPS tags deployed on whip-poor-wills and estimated nonbreeding home ranges and land covers used. We used satellite imagery and stable carbon and nitrogen isotope values from claws grown during the nonbreeding season to analyze how land cover and habitat moisture impacted home range size and relative trophic level. Forest was by far the most prevalent land cover used by whip-poor-wills, occurring in all home ranges and accounting for >80% of diurnal roosting points. We found that less forest, the presence of agriculture, and more edge (irrespective of land cover) were associated with larger home ranges. Stable isotope values differed by broadscale ecoregion but not local land cover characteristics in our study, indicating that regional idiosyncrasies or broadscale processes can be more important in determining stable isotope ratios. Our findings suggest that the loss, fragmentation, and replacement of forest by agriculture in the core of the whip-poor-will’s nonbreeding range may represent a threat to the species, as they rely heavily upon forest, and appear to alter space use in response to changes in forest cover.

Aspects of the nonbreeding ecology of the Tree Pipit Anthus trivialis in and around Amurum Forest Reserve, Jos Plateau, Nigeria

To advance our knowledge about the nonbreeding ecology of the Tree Pipit Anthus trivialis, this study investigated its population dynamics, habitat utilisation and foraging behaviour, from October to December 2018, in and around the Amurum Forest Reserve, located in the guinea savannah zone of Nigeria, West Africa. The study area comprises four main habitat types: gallery forest, rocky outcrop, savannah and farmland. Distance sampling along six transect lines (total length ∼14.2 km) were used to estimate Tree Pipit abundance and density, while habitat utilisation and foraging behaviour were determined from 222 focal observations. Tree Pipit density in the study area averaged about 1 ind. ha-1 and differed significantly between habitats, being highest in savannah, followed by rocky outcrop, farmland and gallery forest. The vegetation characteristics percentage of grass cover, fruiting and flowering plants, and shrubs, as well as insect abundance, significantly influenced the distribution of Tree Pipits in the reserve. Tree Pipits were seen capturing their prey using two foraging techniques, of which gleaning on the ground was the most frequently observed. Variation in Tree Pipit abundance across the three-month study period suggests that many may have been on passage, with relatively few individuals remaining in the area as winter residents.

Light-level geolocation reveals the short-distance non-breeding movements and distribution of tufted puffins throughout the Northeast Pacific Ocean

Comprehensive assessments of cumulative impacts to seabirds have been hindered by an incomplete understanding of temporal and spatial patterns in marine habitat use, particularly during the non-breeding season when seabirds can range widely across the global ocean. Alcids are an important component of the meso-predator biodiversity of the North Pacific Ocean, yet the non-breeding movement ecology and distribution for many of the Pacific Auk species remain poorly quantified. Recent and projected declines for historically robust populations of tufted puffin (Fratercula cirrhata) in Alaska highlight the importance of resolving aspects of the species’ non-breeding ecology, especially the pelagic phenology and distribution. We used light-level geolocation to quantify the annual at-sea distribution of tufted puffins between a major Gulf of Alaska nesting colony (Middleton Island) and heretofore unknown migration routes and wintering areas. Geolocator data from 42 complete migration routes of reproductive adult tufted puffins collected primarily between 2018-2020 revealed that both males and females were short-distance migrants, wintering on average 616 km from their breeding colony. Tufted puffins departed the breeding grounds in early September. Males made fewer stops and arrived earlier to wintering areas than females, however the arrival date to the wintering area was later in 2019 compared to 2018. Males took 30.5 ± 16.7 (± standard deviation) days in 2018 and 30.8 ± 24.6 days in 2019 to arrive at wintering areas. Conversely, females took 36.1 ± 16.8 days in 2018 and 59.8 ± 17.3 days in 2019 to arrive at wintering areas. Adult tufted puffins wintered primarily in the deep offshore waters of the eastern Gulf of Alaska and partially in the adjacent Northeast Pacific Ocean over a period of 151.9 days ± 31.6 with spring migrations starting by late March. Males and females showed consistent spatial distributions within seasons, especially during winter. Tufted puffins shifted southwards throughout the non-breeding season, similar to other Atlantic and Northeast Pacific alcids. Our study provides important information on the at-sea non-breeding phenology and distribution of tufted puffins, which can inform risk assessments for the species including vulnerability to spatially and temporally explicit marine pollution, disease, fisheries by-catch, and ocean-climate variability.

Migration and non-breeding ecology of the Yellow-breasted Chat Icteria virens

Detailed information spanning the full annual cycle is lacking for most songbird populations. We examined breeding, migration, and non-breeding sites for the Yellow-breasted Chat (Icteria virens, chat). We deployed archival GPS tags and light-level geolocators on breeding chats in British Columbia and light-level geolocators in California from 2013 to 2017 to determine migration routes and non-breeding sites. We examined whether chats overwintered in protected areas and characterized the percent of land cover within 1 km. We used a combination of genetics and stable hydrogen isotopes from feathers collected on non-breeding chats in Nayarit, Mexico (2017–2019) and migrating chats in Chiapas, Mexico (2018) and Veracruz, Mexico (2014–2015) to determine subspecies and infer breeding location. Endangered chats in British Columbia followed the Pacific Flyway and spent the non-breeding period in Sinaloa and Nayarit, Mexico. Two out of five chats spent the non-breeding period in protected areas, and the most common landcover type used was tropical or subtropical broadleaf deciduous forest. We found no mixing of eastern and western chats in our Mexico sites, suggesting strong migratory connectivity at the subspecies level. Western chats likely originating from multiple breeding latitudes spent the non-breeding period in Nayarit. Eastern Yellow-breasted Chats likely breeding across various latitudes migrated through Veracruz and Chiapas. Our results provide precise migration routes and non-breeding locations, and describe habitat cover types for chats, notably an endangered population in British Columbia, which may be valuable for habitat protection and conservation efforts.

Non-Breeding Behavior and Diet of Loggerhead Shrikes in an Intensive Agricultural Region

As agricultural conversion has transformed the landscape across the central United States, populations of grassland-associated species, such as those of Lanius ludovicianus (Loggerhead Shrike), have declined. Understanding the ecology and behavior of grassland species in these highly anthropogenic, agricultural landscapes provides vital information for conservation efforts. However, few studies have assessed the ecology and behavior of this species in intensive agricultural areas, especially during the potentially critical nonbreeding season. To help fill these knowledge gaps, we used direct behavioral and larder surveys to describe the non-breeding ecology and behavior of Loggerhead Shrikes in the agriculturally dominated Lower Mississippi Alluvial Valley of Arkansas. Over 3 winters, we observed behavior of Loggerhead Shrikes and found that they spent most of their time perched and scanning for prey (81%), mainly from utility wires (68% of used perches). On average, they made 14.9 ± 1.2 foraging attempts/hr and focused their efforts mostly in right-of-way grasses and adjacent agricultural fields. Overall, individual foraging success rates averaged 58%, did not differ amongst microhabitats, and were comparable to rates reported for breeding Loggerhead Shrikes from other habitats at similar latitudes. Arthropods were the most frequently captured prey (76%; based on direct behavioral surveys), and anurans were the most commonly cached prey (43% of observed cached items). In total, our study highlights the importance of utility wires and rights-of-way for foraging and arthropods as food sources, throughout even the coldest months of the year at this latitude, and increases our understanding of the behavior and ecology of the Loggerhead Shrike in these contexts.

TRANSIENT SWAINSON’S THRUSH (CATHARUS USTULATUS) WINTERING IN THE ANDEAN FOOTHILLS OF ECUADOR ARE ALMOST EXCLUSIVELY YOUNG MALES

We know relatively little about the non-breeding period of most migratory birds. Decades of research on Swainson’s Thrush (Catharus ustulatus) has focused on their breeding ecology, whereas their non-breeding ecology is limited to broad patterns of distribution and migratory stop-over ecology. For the nearly 50 years, the US Breeding Bird Survey recorded declines of 0.7% per year for the Russet-backed Swainson’s Thrush (C. u. swainsonii) subspecies, which spends the non-breeding period in South America. However, there is an insufficient understanding of the constraints across their annual cycle to determine reasons for the sustained decline. In 2013 and 2014, we examined their little studied non-breeding period on the Andean slopes of Ecuador where prior experience showed that they were seasonally abundant. Here rapid deforestation threatens primary forest. We used point counts and radio telemetry to evaluate whether primary forest was used preferentially to recently regenerated second-growth forest. From point counts, 76% of detections and almost all captured individuals occurred in secondary forest. Of 86 birds captured in mist nets, 85 were males and 83 young of the year, indicating a highly skewed ratio in favor of young males. Radio telemetry demonstrated preference for secondary forest, especially for fruiting Cecropia spp. trees, with no apparent territorial behavior by those tracked and with short residency times. A marked decrease in density over the course of the field season suggests an itinerant population possibly tracking the ephemeral use of fruit resources. Alternatively, these temporal and spatial patterns could suggest that this population undergoes a mid-winter intratropical migration or at least landscape-level movements. However, we observed thrushes throughout our extended sampling period suggesting transiency with high turnover. Together, this study documents demographic separation during the non-breeding period with preference for of secondary forest and high transiency, important findings in informing management across the annual cycle.

Do similar foragers flock together? Nonbreeding foraging behavior and its impact on mixed-species flocking associations in a subtropical region

AbstractMixed-species flocks are ubiquitous in forest bird communities, yet the extent to which positive (facilitative) or negative (competitive) interactions structure these assemblages has been a subject of debate. Here, we describe the fine-scale foraging ecology and use network analysis to quantify mixed-species flocking interactions of an insectivorous bird community in hardwood forests of north-central Florida. Our goal was to determine if similarly foraging species are more (facilitation hypothesis) or less (competition hypothesis) likely to associate in flocks, and if foraging ecology can explain intraspecific abundance patterns within flocks. We quantified attack maneuvers, foraging substrate, and foraging microhabitat of all 17 common insectivorous species in these forests and characterized the composition of 92 flocks encountered. Flocking was important in our community; 14 of 17 species joined more than 5% of flocks, and 10 species had flocking propensities of over 0.80. Our results supported both hypothesized mechanisms structuring flock composition. Species had distinct, well-defined foraging niches during the nonbreeding season, but foraging niche overlap among flocking species was greater than expected by chance. Consistent with the facilitation hypothesis, we found that similarly foraging species were significantly more likely to associate in flocks, a result driven by lower association strengths in large-bodied woodpeckers. We found no evidence of assortment by foraging behavior, however, likely because foraging behavior and substrate use showed strong niche partitioning at the fine scale within our community. Intraspecific abundance patterns were significantly linked to foraging substrate use, with live leaf use correlated with high within-flock abundance and relative abundance at study sites. Species that specialized on comparatively less abundant substrates (tree trunks, epiphytes, dead leaves) joined flocks as singletons, showed lower relative abundance, and may exhibit nonbreeding territoriality. Our results highlight the importance of foraging substrate use and mixed-species flocks in structuring the nonbreeding ecology of migratory birds.

Overlooked sexual segregation of habitats exposes female migratory landbirds to threats

Male and female animals often segregate spatially among habitats and landscapes outside of breeding seasons, but it is unclear to what extent conservation efforts account for sexual segregation. Overlooking this phenomenon may result in conservation plans that don’t meet the needs of both sexes, especially when resources or threats vary spatially. We assessed the prevalence of sexual segregation and degree to which current conservation efforts account for it with a review of nonbreeding ecology and conservation planning literature for 66 North American migratory landbirds of conservation concern. Sexual segregation was common in the group—reported for one-third of all species and two-thirds of those with published nonbreeding sex ratios—and did not differ with dimorphism or conservation status. Despite this, only 3% of species distribution models and 8% of conservation recommendations considered sexual segregation, indicating the pattern is widely overlooked. Next, we used the declining Golden-winged Warbler (Vermivora chrysoptera) as a case study to test for sex-bias in habitats prioritized by current conservation efforts. By modeling nonbreeding occupancy and forest cover loss for males and females, we show that females lost twice as much nonbreeding habitat as males from 2000 to 2016, yet existing conservation focal areas remain heavily biased towards male-dominated landscapes. Furthermore, female-dominated habitats face higher rates of conversion than male habitats for multiple species of Neotropical migrants, suggesting the failure to address sexual segregation may compromise the effectiveness of migratory landbird conservation. We recommend greater effort to report sex ratios and create sex-specific habitat assessments and distribution models.

Remote estimation of overwintering home ranges in an elusive, migratory nocturnal bird.

Due to a long running research bias toward the breeding season, there are major gaps in knowledge on the basic nonbreeding ecology of many species, preventing a full‐annual cycle focus in ecology and conservation. Exacerbating this problem is the fact that many species are extremely difficult to detect outside of breeding. Here, we demonstrate a partial solution to this problem by using archival GPS tags to examine the overwintering ecology of a migratory nocturnal bird, the eastern whip‐poor‐will (Antrostomus vociferous). We deployed tags on 21 individuals and were able to recover 11 (52%) one year later. Tags collected high precision (approx. 10 m) points throughout the nonbreeding period. With continuous time movement models, we used these data to estimate overwintering home ranges. All individuals exhibited at least one bounded home range during this phase of the annual cycle, three of eleven had two wintering locations, and home range area ranged from 0.50 to 10.85 ha. All overwintering home ranges contained closed‐canopy forest land cover (42%–100%), and no other land cover type represented >40% of any home range. We found some evidence, with caveats, that total edge within the landscape surrounding the home range was negatively related to home range area. The prevalence of contiguous closed‐canopy forest cover in overwintering home ranges contrasts with apparent breeding habitat preferences, which includes clear‐cuts and other, more open, habitats. This study is the first to reveal key aspects of overwintering space use in this species by using archival GPS to overcome both logistical and methodological limitations. Expanded use of such technology is critical to gathering basic ecological and distributional data, necessary for achieving a more complete understanding of full‐annual cycles of animal populations.

Over-winter ecology and relative density of Canada Warbler Cardellina canadensis in Colombia: the basis for defining conservation priorities for a sharply declining long-distance migrant

SummaryThe Canada Warbler Cardellina canadensis is a steeply declining Neotropical migratory bird and > 50% of its non-breeding range is within the Colombian Andes. Despite being an abundant migrant in Andean forests, the species’ elevational distribution and non-breeding ecology have yet to be studied, thereby precluding the design of effective conservation actions. During four non-breeding periods (2012–2016), we surveyed Colombia’s three Andean ranges, carrying out passive 5-minute point counts between 700 and 3,150 m asl in five habitats (mature forest, secondary growth, forest edges/riparian forest, shade coffee, sun coffee), recording the perpendicular distance, sex, foraging height, and association with mixed species flocks of Canada Warbler. Habitat variables were recorded at each point. Based on 819 passive point counts, Canada Warblers occupied elevations between 750 and 2,300 m, being more abundant between 1,000 and 2,200 m. Relative densities were higher in mature forest compared to shade coffee and secondary forest, and accordingly abundance increased with canopy height. There was no evidence for a difference in elevation or habitat use by males and females. Within forests, birds foraged at mid-levels, 5–15 m above the ground, and the probability of Canada Warblers occurring in mixed species flocks increased with elevation. Models of variation in relative density throughout the Eastern Andes showed a positive relation with cloud cover and above-ground forest biomass, implying a preference for humid, forested regions. Of the areas in the Eastern Andes with high predicted relative density, ∼ 14% overlapped with protected areas and we identify priority areas where protective measures could benefit the conservation status of the species. For maximum effectiveness, conservation actions should focus on protecting forest fragments and initiating reforestation projects at mid-elevations (1,000–2,200 m), as well as supporting agroforestry practices in humid regions of the Colombian Andes.

Great Snipes in sub-Saharan Africa: seasonal patterns of abundance, moult and body mass in relation to age and sex

Great Snipes Gallinago media spend about eight months per year in sub-Saharan Africa, but most aspects of their non-breeding ecology are poorly known. We analysed the seasonal pattern of appearance, flight feather moult (primaries and secondaries), and body mass in relation to age and sex, based on 3,247 birds collected by hunters in 1990–2000 in Benin, Gabon, Cameroon and the Democratic Republic of Congo. Adult males arrived in Africa from mid-August with a suspended flight feather moult. Adult females on average arrived somewhat later, and were about one month behind in the progress of flight feather moult. The adults of both sexes resumed moult immediately upon arrival. Flight feather moult was generally completed by the end of November in males, and end of December in females. Juvenile Great Snipes arrived later than adults and did not moult their flight feathers. The temporal pattern of occurrence at the different study sites suggests a general relocation of snipes from West Africa to Central Africa in October-December. Body masses did not differ between age groups and were generally low from August to February (155–170 g in males and 165–185 g in females). Males apparently departed northwards from late March to late April, and the females about two weeks later. Prior to departure, body mass increased on average with about 50 g (in both sexes), suggesting a departure fuel load of 31–33% above lean body mass. In periods of high and stable mass increase, fuel was deposited at rates of about 0.8–1.3 g/d (or 0.5–0.8% of lean body mass/d). The heaviest males and females had a total body mass of 242 and 250 g, respectively. This kind of traditional natural history data forms an important complement to the new type of data emerging from modern tracking techniques.

Extreme genetic similarity does not predict non‐breeding distribution of two closely related warblers

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Non-Breeding Distribution, Abundance, and Roosting Habitat Use of the American Oystercatcher (Haematopus palliatus frazari) in Sinaloa, Mexico

Abstract. The American Oystercatcher (Haematopus palliatus frazari) is federally listed as endangered in Mexico due to habitat loss and small population size. Recent surveys indicate that the State of Sinaloa supports about half of the breeding population in Mexico. However, no information is available about the non-breeding ecology in Mexico. To assess American Oystercatcher distribution, abundance, and roosting habitat use during the nonbreeding season (3 August 2014-23 January 2015), six bays were surveyed in Sinaloa. A total of 1,351 American Oystercatchers were detected using this area based on maximum count per roosting site at or near high tide. American Oystercatchers roosted in flocks of variable size (3–253 individuals per flock) with Bahia Santa Maria hosting the main roosting sites in Sinaloa. Mangrove islands and mudflats had larger numbers of individuals than expected relative to the availability of those habitats. The non-breeding Sinaloa population comprised approximately 45.0% of the tota...

Persistent annual migration patterns of a specialist seabird

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 593:231-245 (2018) - DOI: https://doi.org/10.3354/meps12459 Persistent annual migration patterns of a specialist seabird Rachael A. Orben1,*, Nobuo Kokubun2, Abram B. Fleishman3,4, Alexis P. Will2,5, Takashi Yamamoto2,6, Scott A. Shaffer3, Rosana Paredes7, Akinori Takahashi2, Alexander S. Kitaysky5 1Department of Fisheries and Wildlife, Oregon State University, Hatfield Marine Science Center, 2030 SE Marine Science Dr., Newport, OR 97365, USA 2National Institute of Polar Research, Tachikawa, Tokyo 190-8518, Japan 3Department of Biological Sciences, San Jose State University, One Washington Square, San Jose, CA 95192-0100, USA 4Conservation Metrics, Inc., 145 McAlister Way, Santa Cruz, CA 95060, USA 5Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA 6Graduate School of Environmental Studies, Nagoya University, Nagoya, Aichi 464-8601, Japan 7Department of Fisheries and Wildlife, 104 Nash Hall, Oregon State University, Corvallis, OR 97331-3803, USA *Corresponding author: raorben@gmail.com ABSTRACT: Specialization can make animals vulnerable to rapid environmental changes. For long-lived seabirds, foraging specialization may make individuals especially sensitive, as climatic changes are currently occurring over the course of one lifetime. The Bering Sea is a dynamic subarctic and arctic ecosystem where windblown sea ice mediates annual productivity and subsequent pathways to upper trophic levels. Red-legged kittiwakes Rissa brevirostris are endemic surface foraging seabirds specializing on myctophid fishes during reproduction. Their degree of specialization outside the breeding season is less understood. We examined their non-breeding ecology (migration, distribution, isotopic niche) during 4 winters with varying sea ice extent. Although we found annual variation in core distributions, diets (as reflected in feather stable isotope signatures), and outbound migratory timing, the winter range of red-legged kittiwakes was restricted to the western regions of the Bering Sea and North Pacific. Contrary to expectations, sea ice did not limit distributions in the Bering Sea in 3 yr: e.g. sea ice associations (<100 km) were infrequent (8.7% mo-1). Yet, their wintering range often overlapped with areas of seasonal ice cover, suggesting range-wide use of sea ice ecosystems. Stress levels measured by corticosterone in feathers were generally low. However, birds that concentrated in the Bering Sea in February had higher stress levels and fed at a lower trophic level than those in the western Aleutians and western subarctic. As conditions change, this persistence in wintering locations, while incurring differential stress levels, may contribute to rapid population fluctuations as has been observed in the recent past. KEY WORDS: Feather corticosterone · Life-history trade-off · Geolocation · Migration · Net‑squared displacement · Stable isotopes · Red-legged kittiwake · Rissa brevirostris Full text in pdf format Supplementary material PreviousNextCite this article as: Orben RA, Kokubun N, Fleishman AB, Will AP and others (2018) Persistent annual migration patterns of a specialist seabird. Mar Ecol Prog Ser 593:231-245. https://doi.org/10.3354/meps12459 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 593. Online publication date: April 12, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.

New discoveries in landbird migration using geolocators, and a flight plan for the future

— 211 — The Auk, Vol. 130, Number 2, pages 211−222. ISSN 0004-8038, electronic ISSN 1938-4254.  2013 by The American Ornithologists’ Union. All rights reserved. Please direct all requests for permission to photocopy or reproduce article content through the University of California Press’s Rights and Permissions website, http://www.ucpressjournals. com/reprintInfo.asp. DOI: 10.1525/auk.2013.130.2.12226 1E-mail: emilymck@yorku.ca Bird migration is a spectacular natural phenomenon that has generated wonder and interest for centuries. Feats of migration inspire amazement—individual birds that weigh less than 200 g may log more than 80,000 km annually (Egevang et al. 2010), travel more than 600 km day–1 (Stutchbury et al. 2009, Akesson et al. 2012), and cross huge geographic barriers such as oceans (Bairlein et al. 2012) and inhospitable deserts (Tottrup et al. 2012b). Despite the vast geography covered during migration, many birds return to the same territories year after year. Although incredible progress has been made in our understanding of bird migration (Newton 2008), many gaps remain in our knowledge of the migration of small birds. The development of miniaturized tracking technology has produced a wave of research into the migratory behavior of small birds (Fig. 1). The inaugural application of miniaturized geolocators (or “geologgers”) on small songbirds in 2007 (Stutchbury et al. 2009) initiated a rapid increase in the number of studies of small landbird migration; there are currently more than 100 permits in North America alone for attaching geolocators to small birds. This technology has been so enthusiastically applied because it provides information critical to conservation and management of declining songbird populations (Faaborg et al. 2010a), as well as the opportunity to test long-standing hypotheses related to endogenous control mechanisms, navigation, and energetics (Robinson et al. 2010). Although more accurate devices may someday be available for tracking small birds, geolocators are currently the only option for migrants that weigh <50 g (Bridge et al. 2011). The main goal of many geolocator studies to date has been the description of little-known migratory routes and wintering sites (e.g., Beason et al. 2012, Stach et al. 2012). As this technique becomes more widely applied (both geographically within species and taxonomically across a broad spectrum of small landbirds), researchers can begin to test hypotheses about migration, nonbreeding ecology, and behavior to inform conservation measures. Many migratory species are declining; thus, a comprehensive understanding of the annual cycle is timely and important for management of species at risk. The purpose of our review is to summarize, for the first time, patterns emerging from geolocator studies. We review new data on (1) migratory connectivity, (2) migratory routes and stopovers, (3) intratropical migration of wintering birds, and (4) migration schedules. We then explore questions that can be answered with emerging geolocator studies, and provide a “flight plan” for future work as direct-tracking technology becomes increasingly smaller and more broadly applied.

Dramatic intraspecific differences in migratory routes, stopover sites and wintering areas, revealed using light-level geolocators

Migratory divides are contact zones between breeding populations that use divergent migratory routes and have been described in a variety of species. These divides are of major importance to evolution, ecology and conservation but have been identified using limited band recovery data and/or indirect methods. Data from band recoveries and mitochondrial haplotypes suggested that inland and coastal Swainson's thrushes (Catharus ustulatus) form a migratory divide in western North America. We attached light-level geolocators to birds at the edges of this contact zone to provide, to our knowledge, the first direct test of a putative divide using data from individual birds over the entire annual cycle. Coastal thrushes migrated along the west coast to Mexico, Guatemala and Honduras. Some of these birds used multiple wintering sites. Inland thrushes migrated across the Rocky Mountains, through central North America to Columbia and Venezuela. These birds migrated longer distances than coastal birds and performed a loop migration, navigating over the Gulf of Mexico in autumn and around this barrier in spring. These findings support the suggestion that divergent migratory behaviour could contribute to reproductive isolation between migrants, advance our understanding of their non-breeding ecology, and are integral to development of detailed conservation strategies for this group.

Non-breeding ecology of the Whinchat Saxicola rubetra in Nigeria

This study on the non-breeding ecology of the Whinchat Saxicola rubetra was conducted in central Nigeria from February through April. The core site was at Gwafan (N09°53', E08°57'), an open scrubland located 10 km east of the city of Jos. The density of Whinchats at Gwafan was 0.58 individuals/ ha, almost three times the overall density around Jos. Time budget observations of colour banded Whinchats, including six birds fitted with radio-transmitters, showed that they spent 80% of their time perching, 11% foraging, 7% preening, and 2% flying. The main method of catching insects was a swoop to the ground. There was no change in perching, preening or flying time but the time some Whinchats spent foraging increased towards the end of the study period. GPS positions of individuals showed that all birds held clearly demarcated territories and defended them against neighbours. Aggressive interactions were also recorded between Whinchats and other bird species. Three birds colour-ringed in 2006 returned to the study site in 2007 and one occupied almost the same territory, indicating site fidelity.

Non-breeding Ecology of Loggerhead Shrikes in Kentucky

Populations of Loggerhead Shrikes (Lanius ludovicianus) across North America have been declining, and factors responsible for this decline remain unclear. Few studies have focused on the availability and use of wintering habitat. Our objectives were to ascertain the size and characteristics of Loggerhead Shrike territories, and examine the hunting behavior of shrikes during the non-breeding season. We observed 1,372 hunting attempts by 19 shrikes; arthropods (65.3%) and other invertebrates (23.3%) were the most common prey. Characteristics of habitat at used and randomly selected, apparently unused isolated and continuous perch sites differed (P = 0.023 and P = 0.021, respectively). Used perches had less grass cover, more bare ground, and denser, shorter vegetation. We found no difference between characteristics of occupied and unoccupied areas (P = 0.34). Non-breeding territories in our study were larger (mean = 85 ha) than those reported for shrikes during the breeding season. The availability of suitable winter habitat does not appear to be limiting Loggerhead Shrike populations in Kentucky. However, most Loggerhead Shrikes winter south of Kentucky where densities are higher, and it is possible that availability of suitable habitat might be a limiting factor in some areas.

Movements and wintering areas of breeding age Thick-billed Murre Uria lomvia from two colonies in Nunavut, Canada

The non-breeding movements of marine birds were poorly known until recently, but this information is essential to understanding the risk to different geographical populations from events on the wintering grounds. We tracked the migration routes and wintering areas of Thick-billed Murre Uria lomvia from two breeding colonies in eastern Canada: Coats Island in northern Hudson Bay and The Minarets, Baffin Island, during the period August 2007–May 2008 using geolocation loggers. Birds from The Minarets moved south rapidly post-breeding and wintered principally off Newfoundland and southern Labrador, or between Newfoundland and southern Greenland, remaining south of 55°N until at least the spring equinox. Those from Coats Island remained in Hudson Bay until at least mid-November, after which they moved rapidly through Hudson Strait to winter in southern Davis Strait and the northern Labrador Sea, mostly north of 55°N. Many individuals stayed throughout the winter in areas of heavy ice cover. Adults from the two colonies appear to be completely segregated in winter and those from Coats Island probably did not enter the area of the winter hunt in Newfoundland. Unexpectedly, some birds from The Minarets wintered in waters beyond the continental slope and outside the distribution of pack ice, demonstrating that particular individuals can be wholly pelagic throughout the winter. Coats Island birds returned through Hudson Strait as soon as open water areas became available in spring. Their sojourn in Hudson Bay coincided very closely with the occurrence of areas with <90% ice cover. In spite of the relatively large error in positions obtained from geolocation loggers, our results demonstrated the value of these devices by uncovering a number of previously unknown aspects of Thick-billed Murre non-breeding ecology in the Northwest Atlantic. Comparison of the non-breeding ecology based on SST experienced in winter show that the winter niche is broader than hitherto assumed, demonstrating that separate populations may experience different selection in the face of climate change.