scholarly journals Circadian flight schedules in night-migrating birds caught on migration

2008 ◽  
Vol 4 (6) ◽  
pp. 619-622 ◽  
Author(s):  
Timothy Coppack ◽  
Simon F Becker ◽  
Philipp J.J Becker
Keyword(s):  
Migratory Birds ◽  
Activity Patterns ◽  
Stopover Site ◽  
Migratory Activity ◽  
Flight Schedules ◽  
Northern European ◽  
Temporal Cues ◽  
Key Factor ◽  
Migrating Birds ◽  
Songbird Migration

Many species of migratory birds migrate in a series of solitary nocturnal flights. Between flights, they stop to rest and refuel for the next segment of their journey. The mechanism controlling this behaviour has long remained elusive. Here, we show that wild-caught migratory redstarts ( Phoenicurus phoenicurus ) are consistent in their flight scheduling. An advanced videographic system enabled us to determine the precise timing of flight activity in redstarts caught at a northern European stopover site during their return trip from Africa. Birds were held captive for three days in the absence of photoperiodic cues (constant dim light) and under permanent food availability. Despite the absence of external temporal cues, birds showed clear bimodal activity patterns: intense nocturnal activity alternating with diurnal foraging and resting periods. The onset of their migratory activity coincided with the time of local sunset and was individually consistent on consecutive nights. The data demonstrate that night-migrating birds are driven by autonomous circadian clocks entrained by sunset cues. This timekeeping system is probably the key factor in the overall control of nocturnal songbird migration.

Circadian and circannual programmes in avian migration

1996 ◽  
Vol 199 (1) ◽  
pp. 39-48 ◽  
Author(s):  
E Gwinner
Keyword(s):  
Migratory Birds ◽  
Circadian System ◽  
Autumn Migration ◽  
Temporal Orientation ◽  
First Year ◽  
Biological Clocks ◽  
Nocturnal Activity ◽  
Migratory Activity ◽  
Migrating Birds ◽  
Relevant Factors

In migratory birds, endogenous daily (circadian) and annual (circannual) rhythms serve as biological clocks that provide the major basis for their temporal orientation. Circannual rhythms are responsible for the initiation of migration both in autumn and spring. This function of timing migrations is particularly important for birds that spend the winter close to the equator where the environment is too constant or irregular to provide accurate timing cues. In addition, circannual rhythms produce programmes that determine both the temporal and the spatial course of migration. In Sylvia warblers, the time programmes controlling autumn migration are organized in a species- or population-specific manner. It has been proposed that, in first-year migrants, the time programme for autumn migration plays a major role in determining migratory distance, thus providing the vector component in a mechanism of vector navigation. It is not yet clear, however, whether this programme does indeed determine migratory distance or whether it only provides the temporal framework within which other factors determine how far a bird flies. Evidence against the first alternative comes from findings indicating that migratory activity can be drastically modified by a constellation of rather specific, but highly relevant, factors and that the resulting changes in migratory activity are not compensated by subsequent increases or decreases of migratory activity. In normally day-active but nocturnally migrating birds, circannual signals cause alterations in the circadian system leading to the development of nocturnal activity. Although the nature of these signals is unknown, there is evidence that changes in the diurnal pattern of melatonin secretion by the pineal gland are associated with, and possibly causally involved in, the waxing and waning of nocturnal activity. These changes in the melatonin pattern presumably also affect general synchronization properties of the circadian system to Zeitgebers in such a way that circadian rhythms adjust faster to new conditions after long transmeridian flights.

scholarly journals The amount of available food affects diurnal locomotor activity in migratory songbirds during stopover

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea Ferretti ◽  
Ivan Maggini ◽  
Sara Lupi ◽  
Massimiliano Cardinale ◽  
Leonida Fusani
Keyword(s):  
Locomotor Activity ◽  
Food Availability ◽  
Migratory Birds ◽  
Migratory Restlessness ◽  
Locomotory Activity ◽  
Central Mediterranean ◽  
Stopover Site ◽  
Stopover Sites ◽  
Migrating Birds ◽  
Spring Stopover

AbstractMigratory passerine birds fly long distances twice a year alternating nocturnal flights with stopovers to rest and replenish energy stores. The duration of each stopover depends on several factors including internal clocks, meteorological conditions, and environmental factors such as availability of food. Foraging entails energetic costs, and if birds need to refuel efficiently, they should modulate their activity in relation to food availability. We investigated how food availability influences locomotor activity in migrating birds of six passerine species at a spring stopover site in the central Mediterranean Sea. We selected birds with low fat scores which we expected to be strongly motivated to refuel. We simulated stopover sites of different quality by providing temporarily caged birds with different amounts of food to simulate scarce to abundant food. We analysed the diurnal locomotory activity as a proxy for food searching effort. Low food availability resulted in an increased diurnal locomotor activity in almost all species, while all birds showed low intensity of nocturnal migratory restlessness. In conclusion, our study shows that food availability in an important determinant of behaviour of migratory birds at stopover sites.

scholarly journals When to depart from a stopover site? Time-since-arrival matters more than current weather conditions

2020 ◽  
Author(s):  
Sebastien Roques ◽  
Pierre-Yves Henry ◽  
Gaetan Guyot ◽  
Bruno Bargain ◽  
Emmanuelle Cam ◽  
...  
Keyword(s):  
Migratory Birds ◽  
Total Duration ◽  
Weather Conditions ◽  
Long Distance ◽  
Migration Strategy ◽  
Stopover Site ◽  
Relative Contribution ◽  
Departure Probability ◽  
Breeding Migration ◽  
Migrating Birds

On the journey to wintering sites, migratory birds usually alternate between flights and stopovers where they rest and refuel. Migration strategies are assumed to differ according to season: a time-minimization pre-breeding migration strategy towards breeding locations, and an energy-minimization post-breeding migration strategy to wintering ones. The duration of flights and stopovers determines the energy requirements and the total duration of the journey. Since migrating birds actually spend most of the time at stopovers, selection to minimize the amount of energy or time spent on migration is very likely to operate on the effectiveness of stopover rest and refueling. Here we address the relative contribution of factors to departure decisions from stopover sites during the post-breeding migration in a long-distance migratory songbird. When capture probability is low it is impossible to assess the variation in body condition over the entire duration of the stopover. To get around this, we use Time Since Arrival (TSA) as a proxy for the changes in the state of individuals during the stopover. We propose that TSA is an integrative proxy for resting, feeding and fattening efficiency. We develop a capture-recapture model to address the relationship between departure probability, estimated TSA, and weather conditions. Using a 20-year dataset from sedge warblers, we show that TSA has a larger effect on departure probability than weather conditions. Low humidity and an increase in atmospheric pressure in the days preceding departure are associated with higher departure probability, but these effects are smaller than that of TSA.

scholarly journals Autumn migratory orientation and route choice in early and late dunlins Calidris alpina captured at a stopover site in Alaska

Biology Open ◽  
2021 ◽  
Vol 10 (4) ◽  
Author(s):  
Susanne Åkesson ◽  
Johanna Grönroos ◽  
Giuseppe Bianco
Keyword(s):  
East Asia ◽  
Pacific Northwest ◽  
North Pacific Ocean ◽  
Gulf Of Alaska ◽  
Stopover Site ◽  
Migratory Activity ◽  
Calidris Alpina ◽  
Migratory Orientation ◽  
The Pacific ◽  
Wintering Areas

ABSTRACT We investigated the migratory orientation of early and late captured dunlins, Calidris alpina, by recording their migratory activity in circular orientation cages during autumn at a staging site in southwest Alaska and performed route simulations to the wintering areas. Two races of dunlins breeding in Alaska have different wintering grounds in North America (Pacific Northwest), and East Asia. Dunlins caught early in autumn (presumably Calidris alpinapacifica) oriented towards their wintering areas (east-southeast; ESE) supporting the idea that they migrate nonstop over the Gulf of Alaska to the Pacific Northwest. We found no difference in orientation between adult and juveniles, nor between fat and lean birds or under clear and overcast skies demonstrating that age, energetic status and cloud cover did not affect the dunlins’ migratory orientation. Later in autumn, we recorded orientation responses towards south-southwest suggesting arrival of the northern subspecies Calidris alpinaarcticola at our site. Route simulations revealed multiple compass mechanisms were compatible with the initial direction of early dunlins wintering in the Pacific Northwest, and for late dunlins migrating to East Asia. Future high-resolution tracking would reveal routes, stopover use including local movements and possible course shifts during migration from Alaska to wintering sites on both sides of the north Pacific Ocean.

scholarly journals Factors influencing fall departure phenology in migratory birds that bred in northeastern North America

The Auk ◽  
2019 ◽  
Author(s):  
Émile Brisson-Curadeau ◽  
Kyle H Elliott ◽  
Pascal Côté
Keyword(s):  
North America ◽  
Short Distance ◽  
Migratory Birds ◽  
Breeding Habitat ◽  
Temperature Changes ◽  
Migration Timing ◽  
Warm Weather ◽  
Breeding Grounds ◽  
Timing Of Migration ◽  
Migrating Birds

Abstract The phenology of migrating birds is shifting with climate change. For instance, short-distance migrants wintering in temperate regions tend to delay their migration in fall during spells of warmer temperature. However, some species do not show strong shifts, and the factors determining which species will react to temperature changes by delaying their migration are poorly known. In addition, it is not known whether a slower migration or a postponed departure creates the observed delays in fall migration because most studies occur far south of the boreal breeding areas making it difficult to separate those 2 mechanisms. We used 22 yr of data at a northern observatory in eastern North America, at the southern edge of the boreal forest, to examine how 21 short-distance migrants responded to changing temperatures. We investigated if those species responding to temperature share life-history features (i.e. diet, size, total migration distance, breeding habitat, timing of migration). The period of migration in each species was, by far, the most important factor predicting the response of a species to temperature. Eight of the 13 species migrating in October changed their migration onset with temperature (usually by delaying migration by 1–2 days/°C), while the migration timing of none of the 8 species migrating in September was dependent on temperature. Furthermore, the absence of a greater migration delay by birds breeding farther from the study site (i.e. Arctic-breeding birds) suggests the mechanism is a postponed departure rather than a slower migration. We conclude that temperature variations in late fall influence the conditions on the breeding grounds, so that birds still present at that time benefit more from postponing their departure in warm weather.

scholarly journals Detoured flight direction responses along the southwest coast of Lake Erie by night-migrating birds

The Auk ◽  
2019 ◽  
Vol 136 (3) ◽  
Author(s):  
David V Gesicki ◽  
Erica L Cech ◽  
Verner P Bingman
Keyword(s):  
Lake Erie ◽  
Migratory Birds ◽  
Western Basin ◽  
Good Opportunity ◽  
Infrared Observations ◽  
The North ◽  
Flight Direction ◽  
Breeding Grounds ◽  
Topographical Feature ◽  
Migrating Birds

Abstract Migratory birds encounter the Great Lakes while moving through eastern North America toward breeding grounds to the North, which offers a good opportunity to study variation in migratory behavior as birds face a potentially influencing topographical feature. Using passive infrared technology, we documented the direction of relatively low-flying, nocturnal, mostly passerine migration in spring along the southern coast of Lake Erie’s western basin. We examined the extent to which spring migrants flew across Lake Erie as a continuation of the inland, northeasterly broad front migratory direction, as determined by weather radar and infrared observations, or displayed a tendency to deviate to more closely follow the direction of the coastline. We found that an estimated 62% of all low-flying migrants deviated their flight directions toward the coast of Lake Erie at 2 coastal sites, Cedar Point and Ottawa, which were characterized by northwest–southeast oriented coastlines. Migrants at a third coastal location, Maumee Bay, which has a more east–west oriented coastline, did not display similarly deviated flight directions. We found that even when winds were energetically favorable for a lake crossing, many migrants still routinely displayed deviated flight directions that approached paralleling the coastline. Further, the mean flight direction at one site, Ottawa, shifted more in the direction of the coastline as the night progressed, suggesting that time of night could influence the shift to a more coastal flight direction. The data indicate that the western basin of Lake Erie acts as a salient topographical feature influencing the flight directions of nocturnal migrants. The data further suggest that birds are making active decisions while in flight, based on current environmental and physiological conditions, about whether to continue to cross Lake Erie or take a coastal detour.

scholarly journals Estimating Origins of Three Species of Neotropical Migrant Songbirds at a Gulf Coast Stopover Site: Combining Stable Isotope and Gis Tools

The Condor ◽  
2007 ◽  
Vol 109 (2) ◽  
pp. 256-267 ◽  
Author(s):  
Keith A. Hobson ◽  
Steve Van Wilgenburg ◽  
Leonard I. Wassenaar ◽  
Frank Moore ◽  
Jeffrey Farrington
Keyword(s):  
North America ◽  
North American ◽  
Gulf Coast ◽  
Conservation Priorities ◽  
Stopover Site ◽  
Avian Migration ◽  
The North ◽  
Gis Tools ◽  
Migrating Birds ◽  
Wood Thrushes

AbstractMeasurement of stable-hydrogen isotopes (δD) in feathers of migrating birds can provide information on where feathers were grown in North America, at least to an approximate band of latitude. This approach has greatly increased our ability to investigate aspects of avian migration and stopover ecology, since origins of unmarked individuals at migration stopover sites can be estimated for the first time. However, few studies have explored the power of combining isotope measurements with geographic information system (GIS) methods. We measured δD values in feathers of hatching-year (HY) Swainson's Thrushes (Catharus ustulatus; n  =  60), Wood Thrushes (Hylocichla mustelina; n  =  113), and Gray Catbirds (Dumetella carolinensis; n  =  158) at Ft. Morgan Peninsula, Alabama (30°10′N, 88°00′W), a migration stopover site along the Gulf coast. By applying an elevation-corrected hydrogen isotope basemap for birds in North America, we derived a GIS surface depicting expected feather δD values across the continent. We then used GIS to constrain the possible origins of the sampled populations by considering only values falling within the North American breeding ranges of the species. We depicted likely origins of migrating birds by the 50% and 75% tolerance limits of the data. Our GIS analysis indicated that our captured populations represented much-reduced regions of possible origin based on the North American breeding distributions. Gradients in abundance data from the North American Breeding Bird Survey (BBS) allowed us to further narrow possible origins within isotopic boundaries for Wood Thrushes and Gray Catbirds. This exercise provided a means by which priority regions and habitats could be assessed at large continental scales based on actual productivity. We suggest the combination of isotopic and GIS tools provides a powerful means to derive conservation priorities and to investigate key factors involved in the ecology of avian migration and stopover.

scholarly journals How hazardous is the Sahara Desert crossing for migratory birds? Indications from satellite tracking of raptors

2009 ◽  
Vol 6 (3) ◽  
pp. 297-300 ◽  
Author(s):  
Roine Strandberg ◽  
Raymond H. G. Klaassen ◽  
Mikael Hake ◽  
Thomas Alerstam
Keyword(s):  
Migratory Birds ◽  
Satellite Telemetry ◽  
Satellite Tracking ◽  
Sahara Desert ◽  
Annual Cycles ◽  
Marsh Harrier ◽  
Circus Aeruginosus ◽  
Course Changes ◽  
Carry Over ◽  
Migrating Birds

We investigated the risk associated with crossing the Sahara Desert for migrating birds by evaluating more than 90 journeys across this desert by four species of raptors (osprey Pandion haliaetus , honey buzzard Pernis apivorus , marsh harrier Circus aeruginosus and Eurasian hobby Falco subbuteo ) recorded by satellite telemetry. Forty per cent of the crossings included events of aberrant behaviours, such as abrupt course changes, slow travel speeds, interruptions, aborted crossings followed by retreats from the desert and failed crossings due to death, indicating difficulties for the migrants. The mortality during the Sahara crossing was 31 per cent per crossing attempt for juveniles (first autumn migration), compared with only 2 per cent for adults (autumn and spring combined). Mortality associated with the Sahara passage made up a substantial fraction (up to about half for juveniles) of the total annual mortality, demonstrating that this passage has a profound influence on survival and fitness of migrants. Aberrant behaviours resulted in late arrival at the breeding grounds and an increased probability of breeding failure (carry-over effects). This study also demonstrates that satellite tracking can be a powerful method to reveal when and where birds are exposed to enhanced risk and mortality during their annual cycles.

scholarly journals Seasonal changes in the altitudinal distribution of nocturnally migrating birds during autumn migration

2015 ◽  
Vol 2 (12) ◽  
pp. 150347 ◽  
Author(s):  
Frank A. La Sorte ◽  
Wesley M. Hochachka ◽  
Andrew Farnsworth ◽  
Daniel Sheldon ◽  
Benjamin M. Van Doren ◽  
...  
Keyword(s):  
Migratory Birds ◽  
Global Climate ◽  
Polar Front ◽  
Migratory Bird ◽  
Atmospheric Conditions ◽  
Altitudinal Distribution ◽  
Long Distance ◽  
Bird Populations ◽  
Intermediate Distance ◽  
Migrating Birds

Wind plays a significant role in the flight altitudes selected by nocturnally migrating birds. At mid-latitudes in the Northern Hemisphere, atmospheric conditions are dictated by the polar-front jet stream, whose amplitude increases in the autumn. One consequence for migratory birds is that the region’s prevailing westerly winds become progressively stronger at higher migration altitudes. We expect this seasonality in wind speed to result in migrants occupying progressively lower flight altitudes, which we test using density estimates of nocturnal migrants at 100 m altitudinal intervals from 12 weather surveillance radar stations located in the northeastern USA. Contrary to our expectations, median migration altitudes deviated little across the season, and the variance was lower during the middle of the season and higher during the beginning and especially the end of the season. Early-season migrants included small- to intermediate-sized long-distance migrants in the orders Charadriiformes and Passeriformes, and late-season migrants included large-bodied and intermediate-distance migrants in the order Anseriformes. Therefore, seasonality in the composition of migratory species, and related variation in migration strategies and behaviours, resulted in a convex–concave bounded distribution of migration altitudes. Our results provide a basis for assessing the implications for migratory bird populations of changes in mid-latitude atmospheric conditions probably occurring under global climate change.

scholarly journals Where in the air? Aerial habitat use of nocturnally migrating birds

2016 ◽  
Vol 12 (11) ◽  
pp. 20160591 ◽  
Author(s):  
Kyle G. Horton ◽  
Benjamin M. Van Doren ◽  
Phillip M. Stepanian ◽  
Andrew Farnsworth ◽  
Jeffrey F. Kelly
Keyword(s):  
Habitat Selection ◽  
Large Scale ◽  
Migratory Birds ◽  
Lower Atmosphere ◽  
Migration Activity ◽  
Maximum Wind ◽  
Eastern Usa ◽  
Migrant Birds ◽  
Spatio Temporal ◽  
Migrating Birds

The lower atmosphere (i.e. aerosphere) is critical habitat for migrant birds. This habitat is vast and little is known about the spatio-temporal patterns of distribution and abundance of migrants in it. Increased human encroachment into the aerosphere makes understanding where and when migratory birds use this airspace a key to reducing human–wildlife conflicts. We use weather surveillance radar to describe large-scale height distributions of nocturnally migrating birds and interpret these distributions as aggregate habitat selection behaviours of individual birds. As such, we detail wind cues that influence selection of flight heights. Using six radars in the eastern USA during the spring (2013–2015) and autumn (2013 and 2014), we found migrants tended to adjust their heights according to favourable wind profit. We found that migrants' flight altitudes correlated most closely with the altitude of maximum wind profit; however, absolute differences in flight heights and height of maximum wind profit were large. Migrants tended to fly slightly higher at inland sites compared with coastal sites during spring, but not during autumn. Migration activity was greater at coastal sites during autumn, but not during spring. This characterization of bird migration represents a critical advance in our understanding of migrant distributions in flight and a new window into habitat selection behaviours.

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