scholarly journals Population trends inVermivorawarblers are linked to strong migratory connectivity

2018 ◽  
Vol 115 (14) ◽  
pp. E3192-E3200 ◽  
Author(s):  
Gunnar R. Kramer ◽  
David E. Andersen ◽  
David A. Buehler ◽  
Petra B. Wood ◽  
Sean M. Peterson ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Population Trends ◽  
Limiting Factors ◽  
Migratory Connectivity ◽  
Migratory Species ◽  
Vermivora Chrysoptera ◽  
Breeding Populations ◽  
Migratory Songbirds ◽  
Weak Connectivity

Migratory species can experience limiting factors at different locations and during different periods of their annual cycle. In migratory birds, these factors may even occur in different hemispheres. Therefore, identifying the distribution of populations throughout their annual cycle (i.e., migratory connectivity) can reveal the complex ecological and evolutionary relationships that link species and ecosystems across the globe and illuminate where and how limiting factors influence population trends. A growing body of literature continues to identify species that exhibit weak connectivity wherein individuals from distinct breeding areas co-occur during the nonbreeding period. A detailed account of a broadly distributed species exhibiting strong migratory connectivity in which nonbreeding isolation of populations is associated with differential population trends remains undescribed. Here, we present a range-wide assessment of the nonbreeding distribution and migratory connectivity of two broadly dispersed Nearctic-Neotropical migratory songbirds. We used geolocators to track the movements of 70Vermivorawarblers from sites spanning their breeding distribution in eastern North America and identified links between breeding populations and nonbreeding areas. Unlike blue-winged warblers (Vermivora cyanoptera), breeding populations of golden-winged warblers (Vermivora chrysoptera) exhibited strong migratory connectivity, which was associated with historical trends in breeding populations: stable for populations that winter in Central America and declining for those that winter in northern South America.

scholarly journals Breeding origins and migratory connectivity at a northern roost of Vaux’s Swift, a declining aerial insectivore

The Condor ◽  
2019 ◽  
Vol 121 (3) ◽  
Author(s):  
Ellis L Smith ◽  
Matthew W Reudink ◽  
Peter P Marra ◽  
Ann E Mckellar ◽  
Steven L Van Wilgenburg
Keyword(s):  
Stable Isotope ◽  
Annual Cycle ◽  
Isotope Analysis ◽  
Vancouver Island ◽  
Cluster Solution ◽  
Migratory Connectivity ◽  
Breeding Sites ◽  
Aerial Insectivores ◽  
Breeding Grounds ◽  
Weak Connectivity

ABSTRACT Populations of Vaux’s Swift (Chaetura vauxi), like those of many aerial insectivores, are rapidly declining. Determining when and where populations are limited across the annual cycle is important for their conservation. Establishing the linkages between wintering and breeding sites and the strength of the connections between them is a necessary first step. In this study, we analyzed 3 stable isotopes (δ13C, δ15N, δ2H) from feathers collected during spring migration from Vaux’s Swifts that perished during a stopover on Vancouver Island, British Columbia, Canada. We previously analyzed claw tissue (grown during winter) from the same individuals, revealing that the swifts likely wintered in 2 or 3 locations/habitats. Here, we used stable isotope analysis of flight feathers presumed to have been grown on, or near, the breeding grounds to determine the likely previous breeding locations and presumed destinations for the swifts. Stable isotope values (δ13C, δ15N, δ2H) showed no meaningful variation between age classes, sexes, or with body size. Surprisingly, ~26% of the birds sampled had feather isotope values that were not consistent with growth on their breeding grounds. For the remaining birds, assigned breeding origins appeared most consistent with molt origins on Vancouver Island. Overall, migratory connectivity of this population was relatively weak (rM = 0.07). However, the degree of connectivity depended on how many winter clusters were analyzed; the 2-cluster solution suggested no significant connectivity, but the 3-cluster solution suggested weak connectivity. It is still unclear whether low migratory connectivity observed for Vaux’s Swift and other aerial insectivores may make their populations more or less vulnerable to habitat loss; therefore, further efforts should be directed to assessing whether aerial insectivores may be habitat limited throughout the annual cycle.

scholarly journals Optimizing the conservation of migratory species over their full annual cycle

2018 ◽  
Author(s):  
R. Schuster ◽  
S. Wilson ◽  
A.D. Rodewal ◽  
P. Arcese ◽  
D. Fink ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Leading Edge ◽  
Habitat Associations ◽  
Western Hemisphere ◽  
Migratory Species ◽  
Land Area ◽  
Conservation Targets ◽  
Trade Offs ◽  
Novel Approach

AbstractLimited knowledge of the distribution, abundance, and habitat associations of migratory species introduces uncertainty about the most effective conservation actions. We used Neotropical migratory birds as a model group to evaluate contrasting approaches to land prioritization to support ≥30% of the global abundances of 117 species throughout the annual cycle in the Western hemisphere. Conservation targets were achieved in 43% less land area in plans based on annual vs. weekly optimizations. Plans agnostic to population structure required comparatively less land area to meet targets, but at the expense of representation. Less land area was also needed to meet conservation targets when human-dominated lands were included rather than excluded from solutions. Our results point to key trade-offs between efforts minimizing the opportunity costs of conservation vs. those ensuring spatiotemporal representation of populations, and demonstrate a novel approach to the conservation of migratory species based on leading-edge abundance models and linear programming to identify portfolios of priority landscapes and inform conservation planners.

scholarly journals Migratory songbirds in the East Asian-Australasian Flyway: a review from a conservation perspective

2015 ◽  
Vol 25 (1) ◽  
pp. 1-37 ◽  
Author(s):  
DING LI YONG ◽  
YANG LIU ◽  
BING WEN LOW ◽  
CARMELA P. ESPAÑOLA ◽  
CHANG-YONG CHOI ◽  
...  
Keyword(s):  
East Asia ◽  
Habitat Loss ◽  
Migratory Birds ◽  
Southern China ◽  
East Asian ◽  
Mainland China ◽  
Conservation Priorities ◽  
Migratory Species ◽  
Long Distance ◽  
Migratory Songbirds

SummaryThe East Asian-Australasian Flyway supports the greatest diversity and populations of migratory birds globally, as well as the highest number of threatened migratory species of any flyway, including passerines (15 species). However it is also one of the most poorly understood migration systems, and little is known about the populations and ecology of the passerine migrants that breed, stop over and winter in the habitats along this flyway. We provide the first flyway-wide review of diversity, ecology, and conservation issues relating to 170 species of long-distance and over 80 short-distance migrants from 32 families. Recent studies of songbird migration movements and ecology is limited, and is skewed towards East Asia, particularly Mainland China, Taiwan, Russia, Japan and South Korea. Strong evidence of declines exists for some species, e.g. Yellow-breasted Bunting Emberiza aureola, but tends to be fragmentary, localised or anecdotal for many others. More species have small breeding ranges (< 250,000 km2) and/or are dependent on tropical forests as wintering habitat than those in any other Eurasian migratory system, and are thus more vulnerable to habitat loss and degradation throughout their ranges. Poorly regulated hunting for food and the pet trade, invasive species and collisions with man-made structures further threaten migratory songbirds at a number of stop-over or wintering sites, while climate change and habitat loss may be of increasing concern in the breeding ranges. A key conservation priority is to carry out intensive field surveys across the region while simultaneously tapping into citizen science datasets, to identify important stop-over and wintering sites, particularly for poorly-known or globally threatened species across South-East Asia and southern China for targeted conservation actions. Additionally, the advent of miniaturised tracking technology, molecular and isotopic techniques can provide novel insights into migration connectivity, paths and ecology for species in this migration system, complementing data from banding exercises and observation-based surveys, and could prove useful in informing conservation priorities. However, until most states along the East Asian-Australasian flyway ratify the Convention on the Conservation of Migratory Species of Wild Animals (CMS) and other cross-boundary treaties, the relative lack of cross-boundary cooperation, coordination and information sharing in the region will continue to present a stumbling block for effective conservation of migratory passerines.

scholarly journals A range-wide domino effect and resetting of the annual cycle in a migratory songbird

2019 ◽  
Vol 286 (1894) ◽  
pp. 20181916 ◽  
Author(s):  
Elizabeth A. Gow ◽  
Lauren Burke ◽  
David W. Winkler ◽  
Samantha M. Knight ◽  
David W. Bradley ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Light Level ◽  
Timing Of Breeding ◽  
Domino Effect ◽  
Breeding Sites ◽  
Breeding Populations ◽  
Migratory Songbird ◽  
Carry Over ◽  
Timing Of Arrival

Latitudinal differences in timing of breeding are well documented but how such differences carry over to influence timing of events in the annual cycle of migratory birds is not well understood. We examined geographical variation in timing of events throughout the year using light-level geolocator tracking data from 133 migratory tree swallows ( Tachycineta bicolor ) originating from 12 North American breeding populations. A swallow's breeding latitude influenced timing of breeding, which then carried over to affect breeding ground departure. This resulted in subsequent effects on the arrival and departure schedules at autumn stopover locations and timing of arrival at non-breeding locations. This ‘domino effect’ between timing events was no longer apparent by the time individuals departed for spring migration. Our range-wide analysis demonstrates the lasting impact breeding latitude can have on migration schedules but also highlights how such timing relationships can reset when individuals reside at non-breeding sites for extended periods of time.

scholarly journals The annual cycle for whimbrel populations using the Western Atlantic Flyway

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260339
Author(s):  
Bryan D. Watts ◽  
Fletcher M. Smith ◽  
Chance Hines ◽  
Laura Duval ◽  
Diana J. Hamilton ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Migratory Birds ◽  
Hudson Bay ◽  
Mackenzie Delta ◽  
Migration Routes ◽  
Long Distance ◽  
Western Atlantic ◽  
Annual Cycles ◽  
Breeding Populations ◽  
Two Populations

Many long-distance migratory birds use habitats that are scattered across continents and confront hazards throughout the annual cycle that may be population-limiting. Identifying where and when populations spend their time is fundamental to effective management. We tracked 34 adult whimbrels (Numenius phaeopus) from two breeding populations (Mackenzie Delta and Hudson Bay) with satellite transmitters to document the structure of their annual cycles. The two populations differed in their use of migratory pathways and their seasonal schedules. Mackenzie Delta whimbrels made long (22,800 km) loop migrations with different autumn and spring routes. Hudson Bay whimbrels made shorter (17,500 km) and more direct migrations along the same route during autumn and spring. The two populations overlap on the winter grounds and within one spring staging area. Mackenzie Delta whimbrels left the breeding ground, arrived on winter grounds, left winter grounds and arrived on spring staging areas earlier compared to whimbrels from Hudson Bay. For both populations, migration speed was significantly higher during spring compared to autumn migration. Faster migration was achieved by having fewer and shorter stopovers en route. We identified five migratory staging areas including four that were used during autumn and two that were used during spring. Whimbrels tracked for multiple years had high (98%) fidelity to staging areas. We documented dozens of locations where birds stopped for short periods along nearly all migration routes. The consistent use of very few staging areas suggests that these areas are integral to the annual cycle of both populations and have high conservation value.

scholarly journals Migration ecology of western gray catbirds

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Kristen A. Mancuso ◽  
Megan A. Fylling ◽  
Christine A. Bishop ◽  
Karen E. Hodges ◽  
Michael B. Lancaster ◽  
...  
Keyword(s):  
British Columbia ◽  
Breeding Season ◽  
Annual Cycle ◽  
Rocky Mountains ◽  
Light Level ◽  
Migratory Connectivity ◽  
Migration Routes ◽  
Stopover Sites ◽  
Breeding Populations ◽  
Northeastern Mexico

Abstract Background For many songbirds in North America, we lack movement details about the full annual cycle, notably outside the breeding season. Understanding how populations are linked spatially between breeding and overwintering periods (migratory connectivity) is crucial to songbird conservation and management. We assessed migratory connectivity for 2 breeding populations of Gray Catbirds (Dumetella carolinensis) west of and within the Rocky Mountains by determining migration routes, stopover sites, and overwintering locations. Additionally, we compared apparent annual survivorship for both populations. Methods We deployed 39 archival light-level geolocators and 21 Global Positioning System (GPS) tags on catbirds in the South Okanagan Valley, British Columbia, Canada, and 32 geolocators and 52 GPS tags in the Bitterroot River Valley, Montana, USA. These devices allowed us to determine migration routes, stopover sites, overwintering locations, and migratory connectivity. Migratory connectivity was quantified using Mantel’s correlation. We used mark-recapture of colour banded catbirds in both sites to estimate apparent annual survivorship. Results We retrieved 6 geolocators and 19 GPS tags with usable data. Gray Catbirds from both populations passed through the Rocky Mountains eastward before heading south towards their overwintering locations in northeastern Mexico and Texas. Stopover sites during fall migration occurred primarily in Montana, Kansas, Oklahoma, and Arkansas. Overwintering locations spanned Texas and 5 states in northeastern Mexico. Individual catbirds used up to 4 distinct sites during the overwintering period. Catbirds separated by almost 500 km during the breeding season overlapped during the non-breeding season, suggesting weak migratory connectivity among western populations (Mantel’s correlation = 0.013, P-value = 0.41). Catbird apparent annual survivorship estimates were higher in British Columbia (0.61 ± 0.06 females; 0.64 ± 0.05 males) than in Montana (0.34 ± 0.05 females; 0.43 ± 0.04 males), though the main driver of these differences remain unclear. Conclusions Our results provide high precision geographic details during the breeding, migration, and overwintering phases of the annual cycle for western Gray Catbirds. Notably, we found that western catbirds followed the Central Flyway as opposed to the Pacific Flyway. We document that catbirds used multiple sites over winter, contrary to the popular belief that this phase of the annual cycle is stationary for most songbirds.

Integrating tracking and resight data enables unbiased inferences about migratory connectivity and winter range survival from archival tags

The Condor ◽  
2021 ◽  
Author(s):  
Clark S Rushing ◽  
Aimee M Van Tatenhove ◽  
Andrew Sharp ◽  
Viviana Ruiz-Gutierrez ◽  
Mary C Freeman ◽  
...  
Keyword(s):  
Transition Probabilities ◽  
Eastern United States ◽  
Migratory Connectivity ◽  
Migratory Species ◽  
Pet Trade ◽  
Winter Range ◽  
Archival Tags ◽  
Breeding Grounds ◽  
Unbiased Estimates ◽  
Further Development

Abstract Archival geolocators have transformed the study of small, migratory organisms but analysis of data from these devices requires bias correction because tags are only recovered from individuals that survive and are re-captured at their tagging location. We show that integrating geolocator recovery data and mark–resight data enables unbiased estimates of both migratory connectivity between breeding and nonbreeding populations and region-specific survival probabilities for wintering locations. Using simulations, we first demonstrate that an integrated Bayesian model returns unbiased estimates of transition probabilities between seasonal ranges. We also used simulations to determine how different sampling designs influence the estimability of transition probabilities. We then parameterized the model with tracking data and mark–resight data from declining Painted Bunting (Passerina ciris) populations breeding in the eastern United States, hypothesized to be threatened by the illegal pet trade in parts of their Caribbean, nonbreeding range. Consistent with this hypothesis, we found that male buntings wintering in Cuba were 20% less likely to return to the breeding grounds than birds wintering elsewhere in their range. Improving inferences from archival tags through proper data collection and further development of integrated models will advance our understanding of the full annual cycle ecology of migratory species.

scholarly journals Elevational niche-shift migration: Why the degree of elevational change matters for the ecology, evolution, and physiology of migratory birds

The Auk ◽  
2021 ◽  
Author(s):  
Jessie L Williamson ◽  
Christopher C Witt
Keyword(s):  
Partial Pressure ◽  
Bird Species ◽  
Seasonal Migration ◽  
Critical Examination ◽  
Niche Shift ◽  
Migratory Connectivity ◽  
Migratory Species ◽  
Arterial Blood ◽  
Air Density ◽  
Elevational Migration

Abstract Elevational migration can be defined as roundtrip seasonal movement that involves upward and downward shifts in elevation. These shifts incur physiological challenges that are proportional to the degree of elevational change. Larger shifts in elevation correspond to larger shifts in partial pressure of oxygen, air density, temperature, and ultraviolet (UV) exposure. Although most avian examples of elevational migration involve subtle shifts that would have minimal impacts on physiology, shifts of any magnitude have previously been considered under the broad umbrella of “elevational migration”. Here, we consider extreme seasonal elevational movements (≥2,000 m), sufficient to shift the elevational dimension of the eco-climatic niche. Migratory bird populations typically maintain inter-seasonal stability in the temperature, precipitation, and elevational aspects of their climatic niches, a tendency that likely reflects genetic physiological specialization on environmental conditions such as atmospheric pressure. A shift of ≥2,000 m involves a ≥20% change in air density and oxygen partial pressure, sufficient to incur functionally impactful declines in arterial blood-oxygen saturation and require compensatory shifts in respiratory physiology. We refer to this phenomenon as elevational niche-shift migration (ENSM). In this review, we analyzed &gt;4 million occurrence records to identify 105 populations, representing 92 bird species, that undergo complete or partial ENSM. We identified key ecological and evolutionary questions regarding the causes and consequences of ENSM. Our synthesis reveals that ENSM has evolved independently in at least 29 avian families spanning 10 orders. Nonetheless, ENSM is rare relative to other forms of seasonal migration, consistent with the general tendency of seasonal niche conservatism by migratory species and evolutionarily conserved elevational range limits. For many migratory species and populations, within-species patterns of migratory connectivity are not sufficiently understood to determine ENSM status. ENSM is distinguished by its scale within the broader phenomenon of elevational migration. Critical examination of ENSM illustrates fundamental constraints on the ecology and evolution of migration systems, topographical influences on geographic patterns of migratory connectivity, and the remarkable metabolic flexibility of certain bird species that allows them to occupy disparate elevations across different seasons.

scholarly journals Malarial parasites as geographical markers in migratory birds?

2006 ◽  
Vol 2 (2) ◽  
pp. 213-216 ◽  
Author(s):  
Sylvia M Fallon ◽  
Robert C Fleischer ◽  
Gary R Graves
Keyword(s):  
North America ◽  
Migratory Birds ◽  
Wide Distribution ◽  
Specific Information ◽  
Population Movements ◽  
Site Specific ◽  
Dendroica Caerulescens ◽  
Bird Populations ◽  
Breeding Populations ◽  
Wintering Range

We tested the hypothesis that malarial parasites ( Plasmodium and Haemoproteus ) of black-throated blue warblers ( Dendroica caerulescens ) provide sufficient geographical signal to track population movements between the warbler's breeding and wintering habitats in North America. Our results from 1083 warblers sampled across the species' breeding range indicate that parasite lineages are geographically widespread and do not provide site-specific information. The wide distribution of malarial parasites probably reflects postnatal dispersal of their hosts as well as mixing of breeding populations on the wintering range. When compared to geographically structured parasites of sedentary Caribbean songbirds, patterns of malarial infections in black-throated blue warblers suggest that host–malaria dynamics of migratory and sedentary bird populations may be subject to contrasting selection pressures.

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