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opencc-zeroDec 2023View details →

Data from: Lunar synchrony, geography, and individual clocks shape autumn migration timing in an avian migrant

Timing programs in animal migrants have been selected to synchronize movements that coincide with predictable resources on the breeding and nonbreeding grounds. Migrants face potential temporal conflicts if their migration schedules benefit from synchrony to conflicting rhythms associated with annual biogeographical (circannual) cues, lunar (circalunar) cues, or individually-repeatable internal clocks. We repeat-tracked individuals of an avian lunaphilic species, Eastern Whip-poor-will (Antrostomus vociferus), for 2–3 successive autumn migrations to determine the influence of the lunar cycle, breeding location, and individual repeatability on migration timing. Almost all birds avoided departing for migration during a full moon, likely to take advantage of the bright moonlight to facilitate visual foraging and enhance pre-migration fattening. However, groups from two latitudinally-distant sampling areas adjusted their autumn departure timing differently relative to the timing of the September full moon, presumably due to differences in seasonal prey availability. Individual repeatability increased throughout autumn migration, suggesting that the factors responsible for shaping migration timing may differ for different migration stages. Our results, that lunar synchrony, local climate, and individual internal clocks appeared to account for much of the variation in migration timing in whip-poor-wills, underscore the value of measuring potentially interacting factors that shape migratory behavior at species, group, and individual levels. It remains unclear if, or how, maintaining individually-repeatable annual migration schedules provides an adaptive benefit for whip-poor-wills or other lunaphilic migrants. Further clarifying the reasons for phenotypic variation in whip-poor-will migration timing will improve predictions of their abilities to adjust migratory movements under changing environmental conditions.

opencc-by-4.0Mar 2020View details →

Fig. 6 in Autumn Migration Of Birds Over Polonyna Borzhava (Ukrainian Carpathians)

Fig. 6. Passage phenology of birds migrating over Polonyna Borzhava in Autumn 2018.

opencc-by-4.0Mar 2020View details →

Fig. 1 in Autumn Migration Of Birds Over Polonyna Borzhava (Ukrainian Carpathians)

Fig. 1. Observation sites used to monitor migration of birds across Polonyna Borzhava in 2018.

opencc-by-4.0Mar 2020View details →

Fig. 2 in Autumn Migration Of Birds Over Polonyna Borzhava (Ukrainian Carpathians)

Fig. 2. Overall dynamics of bird autumn passage across Polonyna Borzhava in autumn 2018.

opencc-zeroSep 2022View details →

Secrets of the night: roost sites and sleep disturbance factors during the autumn migration of first-year white stork Ciconia ciconia

The migration phase of birds is divided into two main states: stopovers and actual migratory flights. For soaring birds, such as storks, nighttime is especially important to conserve energy and to start the next day in favourable weather conditions. Although there is a large number of recent studies on white stork Ciconia ciconia, for example using advanced technologies such as GPS technology, the nocturnal behaviour of the species is still an enigma. Thus, we GSM-GPS-tagged 90 immature storks and checked their nocturnal behaviour, especially roost disturbance, during their first autumn migration from breeding grounds in southern Poland to wintering places in Africa. Storks roosted on three types of site: on buildings, on the ground, or in trees. Birds that roosted on the ground had a higher probability of nighttime disturbance than those that used trees or buildings. The probability of disturbance at night was also related to longitude and latitude; the most easterly birds and those at the start of the migration route were disturbed more often during the night. Furthermore, and interestingly, environmental conditions at roosts were also significantly related to the probability of disturbance; birds roosting at tree sites with higher NDVI (greener) and with higher levels of artificial light both had a lower probability of disturbance. A possible explanation of this could be related to lower potential predatory pressure at night. We found that after long flights birds were disturbed more often at night, and that disturbed birds migrated further the next day. For a better understanding of the nocturnal behaviour of storks, as well as of other migratory birds, the use of modern technological tools with greater precision is recommended.

opencc-by-4.0Dec 2009View details →

Fig. 1 in Change Of Timing Of Autumn Migration In Acrocephalus And Locustella Genus

Fig. 1. Cumulative curve of juvenile Sedge Warbler in 1999 and the 50% and 90% percentiles

opencc-by-4.0Jun 2011View details →

Fig. 1 in Wing-Length, Body Mass And Fat Reserves Of Robins (Erithacus Rubecula) During Autumn Migration In Hungary

Fig. 1. Location of ringing sites

opencc-by-4.0Sep 2016View details →

Fig. 4 in Importance Of Utliukskiy Liman For The Protection Of Waterbirds In The Azov-Black Sea Region During Autumn Migration

Fig. 4. The average number of different orders of waterbirds at Utliukskiy Liman in September.

opencc-zeroDec 2022View details →

A cold high-pressure system over North China hinders the southward migration of Mythimna separata in autumn

Background: <a name="OLE_LINK27"></a>In warm regions or seasons of the year, the planetary boundary layer is occupied by a <a name="OLE_LINK5"></a>huge variety and quantity of insects, but the southward migration of insects (in East Asia) in autumn is still poorly understood. Methods: We collated daily catches of the oriental armyworm (Mythimna separata) moth from 20 searchlight traps from 2014 to 2017 in China. In order to explore the autumn migratory connectivity of M. separata in East China, we analyzed the autumn climate and simulated the autumn migration process of moths. Results: The results confirmed that northward moth migration in spring and summer under the East Asian monsoon system can bring rapid population growth. However, slow southerly wind (blowing towards the north) prevailed over the major summer breeding area in North China (33°- 40°N) due to a cold high-pressure system located there, and this severely disrupts the autumn 'return' migration of this pest. Less than 8% of moths from the summer breeding area successfully migrated back to their winter-breeding region, resulting in a sharp decline of the population abundance in autumn. As northerly winds (blowing towards the south) predominate at the eastern periphery of a high-pressure system, the westward movement of the high-pressure system leads to more northerlies over North China, increasing the numbers of moths migrating southward successfully. Therefore, an outbreak year of M. separata larvae was associated with a more westward position of the high-pressure system during the previous autumn. Conclusion: These results indicate that the southward migration in autumn is crucial for sustaining pest populations of M. separata, and the position of the cold high-pressure system in September is a key environmental driver of the population size in the next year. This study indicates that the autumn migration of insects in East China is more complex than previously recognized, and that the meteorological conditions in autumn are an important driver of migratory insects' seasonal and interannual population dynamics.

opencc-by-4.0Feb 2023View details →

Fig. 2 in Fuel Load And Flight Range Estimation Of Migrating Passerines In The Western Part Of The Carpathian Basin During The Autumn Migration

Fig. 2. Potential flight ranges (+ SE) of passerine species stopping over in Tömörd during

opencc-by-4.0Feb 2023View details →

Fig. 1 in Fuel Load And Flight Range Estimation Of Migrating Passerines In The Western Part Of The Carpathian Basin During The Autumn Migration

Fig. 1. Potential Mediterranean flyway in southern Europe (arrows) and the location of Tömörd

publicDec 2022View details →

A cold high-pressure system over North China hinders the southward migration of Mythimna separata in autumn

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publicSep 2024View details →

Autumn migration of black-necked cranes on the Qinghai-Tibetan and Yunnan-Guizhou Plateaus

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publicApr 2018View details →

Data from: Sora (Porzana carolina) autumn migration habitat use

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publicSep 2022View details →

Secrets of the night: roost sites and sleep disturbance factors during the autumn migration of first-year white stork Ciconia ciconia

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publicDec 2023View details →

Data from: Lunar synchrony, geography, and individual clocks shape autumn migration timing in an avian migrant

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opencc-zeroDec 2016View details →

Data from: Orientation of native versus translocated juvenile Lesser Spotted Eagles (Clanga pomarina) on the first autumn migration

The ontogeny of migration routines used by wild birds remains unresolved. Here we investigated the migratory orientation of juvenile lesser spotted eagles (LSE) (Clanga pomarina) based on translocation and satellite tracking. Between 2004 and 2016, 85 second-hatched juveniles (Abels) were reared in captivity for release into the declining German population, including 50 birds that were translocated 940 km from Latvia. In 2009, we tracked 12 translocated juveniles, as well as 8 native juveniles and 9 native adults, to determine how inexperienced birds come to use strategic migration routes. Native juveniles departed around the same time as the adults and 6 of 8 used the eastern flyway around the Mediterranean, which was used by all adults. In contrast, translocated juveniles departed on average 6 days before native LSEs, and 5 traveled southward and died in the central Mediterranean region. Consequently fewer translocated juveniles (4/12) than native juveniles (7/8) reached Africa. We conclude that juvenile LSEs have a much better chance of learning the strategic southeastern flyway if they leave at an appropriate time to connect with experienced elders upon departure. It is not clear why translocated juveniles departed so early. Regardless, by the end of the year, most juveniles had perished, whether they were translocated (10/12) or not (6/8). The small number of surviving translocated juveniles thus still represents a significant increase in the annual productivity of the German LSE population in 2009.

opencc-zeroDec 2014View details →

Data from: Migration timing and its determinants for nocturnal migratory birds during autumn migration

1. Migration is a common strategy used by birds that breed in seasonal environments, and multiple environmental and biological factors determine the timing of migration. How these factors operate in combination during autumn migration, which is considered to be under weaker time constraints relative to spring migration, is not clear. 2. Here, we examine the patterns and determinants of migration timing for nocturnal migrants during autumn migration in the north-eastern USA using nocturnal reflectivity data from 12 weather surveillance radar stations and modelled diurnal probability of occurrence for 142 species of nocturnal migrants. We first model the capacity of seasonal atmospheric conditions (wind and precipitation) and ecological productivity (vegetation greenness) to predict autumn migration intensity. We then test predictions, formulated under optimal migration theory, on how migration timing should be related to assemblage-level estimates of body size and total migration distance within the context of dietary guild (insectivore and omnivore) and level of dietary plasticity during autumn migration. 3. Our results indicate seasonal declines in ecological productivity delineate the beginning and end of peak migration, whose intensity is best predicted by the velocity of winds at migration altitudes. Insectivorous migrants departed earlier in the season and, consistent with our predictions, large-bodied and long-distance insectivorous migrants departed the earliest. Contrary to our predictions, large-bodied and some long-distance omnivorous migrants departed later in the season, patterns that were replicated in part by insectivorous migrants that displayed dietary plasticity during autumn migration. 4. Our findings indicate migration timing in the region is dictated by optimality strategies, modified based on the breadth and flexibility of migrant's foraging diets, with declining ecological productivity defining possible resource thresholds during which migration occurs when winds at migration altitudes are mild. These observations provide the basis to assess how avian migration strategies may be affected by adjustments in seasonal patterns of atmospheric circulation and ecological productivity that may occur under global climate change.

opencc-zeroNov 2023View details →

Snow depth, temperature, and residual forage experienced by migrating mule deer during autumn (2011–2020), Wyoming, USA

Growing evidence supports the hypothesis that temperate herbivores surf the green wave of emerging plants during spring migration. Despite the importance of autumn migration, few studies have conceptualized resource tracking of temperate herbivores during this critical season. We adapted the Frost Wave Hypothesis (FWH), which posits that animals pace their autumn migration to reduce exposure to snow but increase acquisition of forage. We tested the FWH in a population of mule deer in Wyoming, USA by tracking the autumn migrations of n = 163 mule deer that moved 15–288 km from summer to winter range. Migrating deer experienced similar amounts of snow but 1.4–2.1 times more residual forage than if they had naïve knowledge of when or how fast to migrate. Importantly, deer balanced exposure to snow and forage in a spatial manner. At the fine scale, deer avoided snow near their mountainous summer ranges and became more risk-prone to snow near winter range. Aligning with their higher tolerance of snow and lingering behavior to acquire residual forage, deer increased stopover use by 1 ± 1 day (95% CI) day for every 10% of their migration completed. Our findings support the prediction that mule deer pace their autumn migration with the onset of snow and residual forage but refine the FWH to include movement behavior en route that is spatially dynamic.