The annual cycle of a trans-equatorial Eurasian–African passerine migrant: different spatio-temporal strategies for autumn and spring migration

The small size of the billions of migrating songbirds commuting between temperate breeding sites and the tropics has long prevented the study of the largest part of their annual cycle outside the breeding grounds. Using light-level loggers (geolocators), we recorded the entire annual migratory cycle of the red-backed shrike Lanius collurio , a trans-equatorial Eurasian-African passerine migrant. We tested differences between autumn and spring migration for nine individuals. Duration of migration between breeding and winter sites was significantly longer in autumn (average 96 days) when compared with spring (63 days). This difference was explained by much longer staging periods during autumn (71 days) than spring (9 days). Between staging periods, the birds travelled faster during autumn (356 km d –1 ) than during spring (233 km d –1 ). All birds made a protracted stop (53 days) in Sahelian sub-Sahara on southbound migration. The birds performed a distinct loop migration (22 000 km) where spring distance, including a detour across the Arabian Peninsula, exceeded the autumn distance by 22 per cent. Geographical scatter between routes was particularly narrow in spring, with navigational convergence towards the crossing point from Africa to the Arabian Peninsula. Temporal variation between individuals was relatively constant, while different individuals tended to be consistently early or late at different departure/arrival occasions during the annual cycle. These results demonstrate the existence of fundamentally different spatio-temporal migration strategies used by the birds during autumn and spring migration, and that songbirds may rely on distinct staging areas for completion of their annual cycle, suggesting more sophisticated endogenous control mechanisms than merely clock-and-compass guidance among terrestrial solitary migrants. After a century with metal-ringing, year-round tracking of long-distance migratory songbirds promises further insights into bird migration.

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The influence of morphological variation on migration performance in a trans-hemispheric migratory songbird

Animal Migration ◽

10.1515/ami-2015-0005 ◽

2015 ◽

Vol 2 (1) ◽

pp. 86-95 ◽

Cited By ~ 4

Author(s):

Lawrence Lam ◽

Emily A. McKinnon ◽

James D. Ray ◽

Myrna Pearman ◽

Glen T. Hvenegaard ◽

...

Keyword(s):

Body Size ◽

Morphological Traits ◽

Light Level ◽

Spring Migration ◽

Future Research ◽

Long Distance ◽

Intrinsic Factors ◽

Migratory Songbirds ◽

Migratory Songbird ◽

Direct Tracking

AbstractFor long-distance migratory songbirds, morphological traits such as longer wings and a smaller body size are predicted to increase migration efficiency. Due to previous limitations in our ability to track the long-distance journeys of small-bodied birds, the relationship between morphology and start-to-finish migration performance has never been fully tested in free-living songbirds. Using direct-tracking data obtained from light-level geolocators, we examined the effects of morphological factors (wing and body size) on spring and fall migration performance (flight speed, duration of stopovers, total stopovers taken) of a widely distributed, trans-hemispheric migratory songbird, the purple martin (Progne subis) (n = 120). We found that smaller-bodied birds spent fewer days at stopovers along fall migration, but larger-bodied birds spent fewer days at stopover and took fewer stopovers during spring migration. More of the variation in fall migration performance was explained by morphology, as compared to spring migration, possibly indicating a larger influence of environmental conditions on spring performance. Overall, our results partially support long-standing and previously untested predictions regarding the influence of intrinsic factors on migration performance. Future research should examine the influence of environmental variation on migration performance as well as additional morphological traits that may contribute to migration performance.

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From Mediterranean to Scandinavia—timing and body mass condition in four long distance migrants

Ornis Svecica ◽

10.34080/os.v25.22552 ◽

2015 ◽

Vol 25 (1–2) ◽

pp. 51-58

Author(s):

Christos Barboutis ◽

Leo Larsson ◽

Åsa Steinholtz ◽

Thord Fransson

Keyword(s):

Body Mass ◽

Arrival Time ◽

Long Distance ◽

Breeding Sites ◽

Swedish Study ◽

Collared Flycatcher ◽

Stopover Sites ◽

Early Arrival ◽

Breeding Grounds ◽

Pass Through

In spring, long-distance migrants are considered to adopt a time-minimizing strategy to promote early arrival at breeding sites. The phenology of spring migration was examined and compared between two insular stopover sites in Greece and Sweden for Icterine Warbler, Wood Warbler, Spotted Flycatcher and Collared Flycatcher. All of them migrate due north which means that some proportion of birds that pass through Greece are heading to Scandinavia. The Collared Flycatcher had the earliest and the Icterine Warbler the latest arrival time. The differences in median dates between Greece and Sweden were 3–4 weeks and the passages in Sweden were generally more condensed in time. The average overall speed estimates were very similar and varied between 129 and 137 km/d. In most of the species higher speed estimates were associated with years when birds arrived late in Greece. After crossing continental Europe birds arrive at the Swedish study site with significantly higher body masses compared to when they arrive in Greece and this might indicate a preparation for arriving at breeding grounds with some overload.

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A full annual perspective on sex-biased migration timing in long-distance migratory birds

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2018.2821 ◽

2019 ◽

Vol 286 (1897) ◽

pp. 20182821 ◽

Cited By ~ 12

Author(s):

Martins Briedis ◽

Silke Bauer ◽

Peter Adamík ◽

José A. Alves ◽

Joana S. Costa ◽

...

Keyword(s):

Annual Cycle ◽

Migratory Birds ◽

Long Distance ◽

Breeding Sites ◽

Arrival Times ◽

Migration Timing ◽

Female Migration ◽

Proximate Determinants ◽

Carry Over ◽

And Migration

In many taxa, the most common form of sex-biased migration timing is protandry—the earlier arrival of males at breeding areas. Here we test this concept across the annual cycle of long-distance migratory birds. Using more than 350 migration tracks of small-bodied trans-Saharan migrants, we quantify differences in male and female migration schedules and test for proximate determinants of sex-specific timing. In autumn, males started migration about 2 days earlier, but this difference did not carry over to arrival at the non-breeding sites. In spring, males on average departed from the African non-breeding sites about 3 days earlier and reached breeding sitesca4 days ahead of females. A cross-species comparison revealed large variation in the level of protandry and protogyny across the annual cycle. While we found tight links between individual timing of departure and arrival within each migration season, only for males the timing of spring migration was linked to the timing of previous autumn migration. In conclusion, our results demonstrate that protandry is not exclusively a reproductive strategy but rather occurs year-round and the two main proximate determinants for the magnitude of sex-biased arrival times in autumn and spring are sex-specific differences in departure timing and migration duration.

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

The Condor ◽

10.1093/condor/duz034 ◽

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.

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Migrating Curlews on Schedule: Departure and Arrival Patterns of a Long-Distance Migrant Depend on Time Rather than on Wind Conditions

10.21203/rs.3.rs-101849/v1 ◽

2020 ◽

Author(s):

Philipp Schwemmer ◽

Moritz Mercker ◽

Klaus Heinrich Vanselow ◽

Pierrick Bocher ◽

Stefan Garthe

Keyword(s):

Wadden Sea ◽

Bird Species ◽

Weather Conditions ◽

Internal Clock ◽

Migratory Bird ◽

Long Distance ◽

Breeding Sites ◽

Timing Of Migration ◽

Spatio Temporal ◽

Selection Operator

Abstract Background: Choosing the appropriate time to depart for spring migration is crucial to achieving a successful subsequent breeding season among migratory bird species. We expected Eurasian Curlews (Numenius arquata) to start their migration during favourable weather conditions and to adjust their flight heights to prevailing wind conditions.Methods: We equipped 23 curlews with Global Positioning System data loggers to record the spatio-temporal patterns of their departure from and arrival at their wintering site in the Wadden Sea, as well as the first part of their migration. We obtained data for 42 curlew migrations over a period of 6 years. Departure and arrival dates were related to 73 meteorological and bird-related predictors using the least absolute shrinkage and selection operator (LASSO) to identify drivers of departure and arrival decisions.Results: Curlews migrated almost exclusively to the western part of Russia for breeding. They left the Wadden Sea mainly during the evening hours from mid- to late April and returned between the end of June and mid-July. There was no difference in departure times between the sexes, but males tended to return from their breeding sites later than females. Flight speeds of the birds increased significantly with increasing tailwind component, suggesting that they timed their migration according to favourable wind conditions. However, curlews left the Wadden Sea during various wind and weather conditions, with significant numbers leaving during headwind conditions, in contrast to the apparent wind-driven start of migration. Curlews migrated at very low altitudes during tailwind conditions, but flew significantly higher during headwind conditions, at altitudes of up to several kilometres. Departure dates varied by <4 days in individual curlews that were tagged over consecutive years. Conclusions: Our results suggest that the start of migration in a long-distance migrant mainly depends on the date and is independent of weather conditions. Given the high repeatability of the departure day among subsequent years, this clearly suggests the existence of an internal clock prompting the start of migration. Further insights into the timing of migration in immatures and closely related birds might help us to understand the genetic mechanisms triggering temporal migration patterns.

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Habitat loss on the breeding grounds is a major contributor to population declines in a long-distance migratory songbird

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2020.3164 ◽

2021 ◽

Vol 288 (1949) ◽

Author(s):

Michael T. Hallworth ◽

Erin Bayne ◽

Emily McKinnon ◽

Oliver Love ◽

Junior A. Tremblay ◽

...

Keyword(s):

Habitat Loss ◽

Annual Cycle ◽

Forest Loss ◽

Population Declines ◽

Migration Routes ◽

Long Distance ◽

Migratory Songbirds ◽

Breeding Grounds ◽

Migratory Songbird ◽

Land Use Practices

Many migratory species are declining and for most, the proximate causes of their declines remain unknown. For many long-distance Neotropical migratory songbirds, it is assumed that habitat loss on breeding or non-breeding grounds is a primary driver of population declines. We integrated data collected from tracking technology, community science and remote sensing data to quantify migratory connectivity (MC), population trends and habitat loss. We quantified the correlation between forest change throughout the annual cycle and population declines of a long-distance migratory songbird, the Connecticut warbler ( Oporornis agilis , observed decline: −8.99% yr −1 ). MC, the geographic link between populations during two or more phases of the annual cycle, was stronger between breeding and autumn migration routes (MC = 0.24 ± 0.23) than between breeding and non-breeding locations (MC = −0.2 ± 0.14). Different Connecticut warbler populations tended to have population-specific fall migration routes but overlapped almost completely within the northern Gran Chaco ecoregion in South America. Cumulative forest loss within 50 km of breeding locations and the resulting decline in the largest forested patch index was correlated more strongly with population declines than forest loss on migratory stopover regions or on wintering locations in South America, suggesting that habitat loss during the breeding season is a driver of observed population declines for the Connecticut warbler. Land-use practices that retain large, forested patches within landscapes will likely benefit breeding populations of this declining songbird, but further research is needed to help inform land-use practices across the full annual cycle to minimize the impacts to migratory songbirds and abate ongoing population declines.

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Concentration of a widespread breeding population in a few critically important nonbreeding areas: Migratory connectivity in the Prothonotary Warbler

The Condor ◽

10.1093/condor/duz019 ◽

2019 ◽

Vol 121 (2) ◽

Cited By ~ 12

Author(s):

Christopher M Tonra ◽

Michael T Hallworth ◽

Than J Boves ◽

Jessie Reese ◽

Lesley P Bulluck ◽

...

Keyword(s):

Annual Cycle ◽

Large Scale ◽

Light Level ◽

Breeding Population ◽

Migratory Bird ◽

Migratory Connectivity ◽

Long Distance ◽

Breeding Range ◽

Migratory Routes ◽

Prothonotary Warbler

Abstract One of the greatest challenges to informed conservation of migratory animals is elucidating spatiotemporal variation in distributions. Without such information, it is impossible to understand full-annual-cycle ecology and effectively implement conservation actions that address where and when populations are most limited. We deployed and recovered light-level geolocators (n = 34) at 6 breeding sites in North America across the breeding range of a declining long-distance migratory bird, the Prothonotary Warbler (Protonotaria citrea). We sought to determine migratory routes, stopover location and duration, and the location of overwintering grounds. We found that the species exhibits a large-scale, east‒west split in migratory routes and weak migratory connectivity across its range. Specifically, almost all individuals, regardless of breeding origin, overlapped in their estimated wintering location in northern Colombia, in an area 20% the size of the breeding range. Additionally, most of the individuals across all breeding locations concentrated in well-defined stopover locations in Central America while en route to Colombia. Although error inherent in light-level geolocation cannot be fully ruled out, surprisingly much of the estimated wintering area included inland areas even though the Prothonotary Warbler is considered a specialist on coastal mangroves in winter. Based on these results, conservation efforts directed at very specific nonbreeding geographical areas will potentially have benefits across most of the breeding population. Our findings highlight the importance of using modern technologies to validate assumptions about little-studied portions of a species’ annual cycle, and the need to distribute sampling across its range.

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Seasonal, Age, and Sex Differences in Weight, Fat Reserves, and Plasma Corticosterone in Western Sandpipers

The Condor ◽

10.1093/condor/105.1.13 ◽

2003 ◽

Vol 105 (1) ◽

pp. 13-26 ◽

Cited By ~ 4

Author(s):

Kathleen M. O'Reilly ◽

John C. Wingfield

Keyword(s):

Annual Cycle ◽

San Diego ◽

Spring Migration ◽

Autumn Migration ◽

Calidris Mauri ◽

Fat Reserves ◽

Stopover Sites ◽

Breeding Grounds ◽

Western Sandpipers ◽

Bodega Bay

Abstract Western Sandpipers (Calidris mauri) were followed throughout their annual cycle along the Pacific Coast of North America. Changes in body condition and corticosterone were tracked at two overwintering sites (Ensenada, Mexico, and San Diego, California), four migration stopover sites (Bodega Bay, California, Grays Harbor and False Bay, Washington, and Hartney Bay, Alaska), and a breeding site (Nome, Alaska). Adult males and females had elevated weight and fat scores during spring migration, breeding, and autumn migration relative to lean levels during winter. Although elevated mass and fat reserves may hinder escape from predators and are not necessary at wintering sites with benign conditions, the cost-benefit trade-offs with weight and agility shift during migration and breeding. Extra fat and muscle are necessary for fueling the long flight to and from the breeding grounds and serve as a hedge against unpredictable food and weather conditions on the breeding grounds. First-year birds weighed less and had lower fat reserves at smaller stopover sites than migrants at a large stopover site. Plasma levels of corticosterone revealed seasonal differences in the adrenocortical response to stress, although initial levels were fairly consistent across seasons. The highest stress response of the annual cycle in males was during autumn migration, in contrast to the lowest levels during early spring migration, breeding, and overwintering. Late-spring migrants and autumn premigrants had intermediate stress responses. An emerging pattern from this and other shorebird studies is that migrants with imminent flights of more than 1000 km have elevated corticosterone levels. Diferencias Estacionales de Edad y Sexo en Peso, Reservas de Grasa y Corticosterona Plasmática en Calidris mauri Resumen. Se siguieron individuos de Calidris mauri a través de su ciclo anual a lo largo de la costa Pacífica de Norteamérica. Se evaluaron los cambios en la condición corporal y la corticosterona en dos sitios de invernación (Ensenada, México y San Diego, California), cuatro sitios de escala migratoria (Bodega Bay, California, Grays Harbor y False Bay, Washington, y Hartney Bay, Alaska) y un sitio reproductivo (Nome, Alaska). Los machos y hembras adultos tuvieron pesos y niveles de grasa altos durante las épocas de migración de primavera, reproducción y migración de otoño con relación a los niveles magros del invierno. Aunque presentar masa elevada y reservas de grasa puede limitar el escape de los depredadores y no es necesario en los sitios de invernada con condiciones benignas, existe un cambio en la solución de compromiso entre el costo-beneficio del peso y la agilidad de vuelo durante la migración y la reproducción. La grasa y músculos adicionales son necesarios para proveer combustible para los largos vuelos hacia y desde las áreas de reproducción y sirven como protección contra condiciones alimenticias y climáticas impredecibles en las áreas reproductivas. Las aves añales pesaron menos y tuvieron menos reservas grasas en sitios de escala pequeños que los migrantes en un sitio de escala grande. Los niveles plasmáticos de corticosterona mostraron diferencias estacionales en la respuesta adrenocórtica al estrés, aunque los niveles iniciales fueron relativamente consistentes a través de las estaciones. La respuesta al estrés más alta del ciclo anual de los machos se presentó durante la migración de otoño, contrastando con los niveles más bajos durante el inicio de la migración de primavera, la época reproductiva y la época de invernación. Las aves que migraron temprano en la primavera y las premigrantes de otoño presentaron niveles intermedios de respuesta al estrés. Un patrón que emerge de éste y otros estudios sobre aves marinas es que las migratorias que hacen vuelos de más de 1000 km presentan niveles elevados de corticosterona.

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A green wave of saltmarsh productivity predicts the timing of the annual cycle in a long-distance migratory shorebird

Scientific Reports ◽

10.1038/s41598-020-77784-7 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Joseph A. M. Smith ◽

Kevin Regan ◽

Nathan W. Cooper ◽

Luanne Johnson ◽

Elizabeth Olson ◽

...

Keyword(s):

Life History ◽

Salt Marsh ◽

Annual Cycle ◽

Latitudinal Gradient ◽

Atlantic Coast ◽

Breeding Habitat ◽

Spatial And Temporal Variation ◽

Spring Temperature ◽

Long Distance ◽

Breeding Sites

AbstractUnderstanding how migratory animals respond to spatial and temporal variation in habitat phenology is critical for identifying selection pressures and tradeoffs at different life history stages. We examined the influence of breeding habitat phenology on life history timing of the eastern willet (Tringa semipalmata semipalmata) across a latitudinal gradient of breeding sites on the east coast of North America. To describe migration and life history timing, we deployed light-level geolocators on willets at breeding sites in New Jersey, Massachusetts and Maine, USA and evaluated additional data on life history timing and migratory connectivity from previous studies, eBird and band recoveries. Willets from Nova Scotia to Georgia winter exclusively on the Atlantic coast of northern South America and share common stopover sites. The timing of wintering site departure, breeding site arrival, nesting and southbound departure was later for birds breeding at higher latitudes while the duration of all life phases was similar across sites. Regardless of latitude, nesting corresponded with a consistent stage of seasonal salt marsh biomass accumulation and with peak spring temperature acceleration (GDD jerk). Temperature acceleration and salt marsh biomass were closely correlated with each other across the 11° latitudinal gradient we examined and with the timing of nest initiation across the northern 6° of this gradient. For this northern 6° of latitude, these results suggest that the timing of migration and breeding events in the annual cycle of eastern willets is constrained by a phenological “green wave” of spring salt marsh productivity at breeding sites.

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Weather at the winter and stopover areas determines spring migration onset, progress, and advancements in Afro-Palearctic migrant birds

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1920448117 ◽

2020 ◽

Vol 117 (29) ◽

pp. 17056-17062 ◽

Cited By ~ 4

Author(s):

Birgen Haest ◽

Ommo Hüppop ◽

Franz Bairlein

Keyword(s):

Climate Change ◽

Migratory Birds ◽

Spring Migration ◽

Long Distance ◽

Spring Phenology ◽

Migration Timing ◽

Climate Change Effects ◽

Breeding Grounds ◽

Migration Phenology ◽

Exogenous Factors

Climate change causes changes in the timing of life cycle events across all trophic groups. Spring phenology has mostly advanced, but large, unexplained, variations are present between and within species. Each spring, migratory birds travel tens to tens of thousands of kilometers from their wintering to their breeding grounds. For most populations, large uncertainties remain on their exact locations outside the breeding area, and the time spent there or during migration. Assessing climate (change) effects on avian migration phenology has consequently been difficult due to spatial and temporal uncertainties in the weather potentially affecting migration timing. Here, we show for six trans-Saharan long-distance migrants that weather at the wintering and stopover grounds almost entirely (∼80%) explains interannual variation in spring migration phenology. Importantly, our spatiotemporal approach also allows for the systematic exclusion of influences at other locations and times. While increased spring temperatures did contribute strongly to the observed spring migration advancements over the 55-y study period, improvements in wind conditions, especially in the Maghreb and Mediterranean, have allowed even stronger advancements. Flexibility in spring migration timing of long-distance migrants to exogenous factors has been consistently underestimated due to mismatches in space, scale, time, and weather variable type.

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