Evolution of Bird Migration

An intensive migratory route of the Crane passes
through the interfluve of the Dnieper River and
Molochna River in the north-northeast direction
during spring passage and the southwest-south
direction during autumn passage. The most of
migratory birds make a stopover in the Biosphere Reserve «Askania Nova» and its
surroundings with maximum concentration numbers about 44 thousand individuals.
There is a shift in timing of passage to an earlier start in spring and a later end in
autumn, also occur occasional winterings of small flocks of the Common Crane.
The one-time accidental visit of 5 individuals of the Siberian White Crane and their
stay in the Common Crane's flocks during 9 days were registered.
The Demoiselle Crane is a bird of passage and nesting species in the region which
does not form large concentrations within the reserve.
Excessive hunting pressure is a main factor for spatial distribution of cranes in the
reserve's region which results in very numerous concentrations of flocks within the
protected areas.
Key words: migration, Crane, biosphere reserve, population dynamics

We studied the population trend and movements of the Song Thrush during the winter near the Tyrrhenian coast in the region of Latium, from 2012 to 2014, in order to establish the timing of spring migration. During standardized mist-netting we captured and ringed 431 birds. The data collected indicate that the study area is mainly visited by wintering thrushes with significant year-to year fluctuations in the number of birds. Based on the information gathered during this study, confirmed by the results of other
studies carried out in southern Italy and France, we assume that spring migration starts in Latium between the second and third decade of February.

The White Sea ornithological expedition took place between 21st September and 10th October,
and was organized by Finnish Environment Institute as a part of RECMAB project (Research,
Conservation and Monitoring Project of Migratory Arctic Birds on the Baltic Sea and White Sea).
The aim of RECMAB is to identify the most important congregating areas of migratory arctic
waterbids in the Baltic Sea and White Sea.
The expedition team found many important congregating areas of which at least one was evidently
unknown previously. Studies during the expedition suggested that remarkable congregating
areas also exist in the vicinity of the White Sea Channel and the Kanin Peninsula. Transect
line counts revealed that the densities of staging birds on the sea outside congregating areas
were generally low.
During the expedition a lot of data on patterns of arctic bird migration was gathered; e.g. on
daily rhythm, directions, routes, magnitude, and timing of migration. There were obvious differences
between species in the dynamics and magnitude of migration. Some species fly in broad
fronts, while others tend to follow coast lines. In general, more birds were seen migrating in the
morning, although some species continued to migrate actively throughout the day.
The expedition was carried out by ship. Compared to aeroplane, that has also been used for research
on congregating areas of arctic birds, ship has some benefits: lower costs, long observation
times for each recorded individual, and good changes to detect more elusive and more sparsely
distributed species. On the other hand, ship is slow, and areas of shallow waters, which are
important for many arctic waterbirds as staging areas, can not be reached by ship. Intensive aerial
surveys are essential for research into important congregating areas in large sea areas.

The circular distribution of the willow warbler Phylloscopus trochilus around the Baltic Sea shares many features with the classic examples of ring species; however, the system is much younger. It has previously been shown that a secondary contact zone is located in central Scandinavia, where there are narrow clines for several morphological traits coincident with a migratory divide. Here we analyse multiple traits and genes from> 1700 males captured on breeding territories at 77 sites spread around the Baltic Sea to ...

ABSTRACT Food availability and acquisition are critical components of a stopover site's suitability, but we know relatively little about how changes in food availability affect the stopover ecology of migrating landbirds. We examined fruit and arthropod availability in three habitats, studied foraging behavior and diet, and investigated use versus availability for passerines migrating through southwestern Idaho in autumn. Hemiptera dominated foliage-dwelling arthropod communities in all three habitats, whereas Hymenoptera were most numerous among ground-dwelling arthropods. Mountain shrubland had relatively high biomass of both ground-dwelling and foliage-dwelling arthropods, whereas conifer forest had high biomass of foliage-dwelling arthropods only and shrubsteppe had high biomass of ground-dwelling arthropods only. Species' foraging behavior varied, but most species foraged in mountain shrubland more often than expected by chance. Diets of most species included a high proportion of certain Hemiptera and Hymenoptera with smaller proportions of Coleoptera, Diptera, and Heteroptera; Coleoptera and some Hemiptera were consistently preferred by most species. Importantly, all 19 bird species examined consumed some fruit, and this is the first documentation of frugivory for two warbler species. These data point to the importance of several arthropod taxa, especially the Hemiptera and Hymenoptera, and fruits to landbirds migrating in mountain shrubland in autumn. Finally, we found no effect of annual variation of fruit or arthropod abundance on migrants' energetic condition, suggesting that food was sufficient for mass gain in all years of this study and/or that foraging behavior may be plastic enough to allow birds to gain mass despite annual differences in food availability. La disponibilidad y la adquisición de alimento son componentes críticos de la calidad de un sitio de parada, pero sabemos relativamente poco sobre cómo los cambios en la disponibilidad de alimento afectan la ecología de parada de las aves terrestres migratorias. Examinamos la disponibilidad de frutos y artrópodos en tres hábitats, estudiamos el comportamiento de forrajeo y la dieta e investigamos el uso versus la disponibilidad para los paserinos que migran en otoño a través del sudoeste de Idaho. Los hemípteros dominaron las comunidades de artrópodos que viven en el follaje en los tres hábitats, mientras que los himenópteros fueron más numerosos entre los artrópodos que viven en el suelo. El arbustal de montaña tuvo una biomasa relativamente alta de artrópodos que viven en el suelo y en el follaje, mientras que el bosque de coníferas tuvo una biomasa alta sólo de artrópodos que viven en el follaje y la estepa arbustiva tuvo una biomasa alta sólo de artrópodos que viven en el suelo. El comportamiento de forrajeo de las especies varió, pero la mayoría de las especies forrajearon más frecuentemente en el arbustal de montaña que lo esperado por azar. La dieta de la mayoría de las especies incluyó una alta proporción de hemípteros e himenópteros con una menor proporción de coleópteros, dípteros y heterópteros; los coleópteros y algunos hemípteros fueron consistentemente preferidos por la mayoría de las especies. De modo destacado, todas las 19 especies de aves examinadas consumieron algo de frutos y este es el primer registro de frugivoría por parte de dos especies de arañeros. Estos datos señalan la importancia en el arbustal de montaña de varios taxones de artrópodos, especialmente de hemípteros e himenópteros, y de los frutos para las aves terrestres migratorias de otoño. Finalmente, no encontramos un efecto de la variación anual de la abundancia de frutos o artrópodos sobre la condición energética de los migrantes, sugiriendo que el alimento fue suficiente para el aumento de la masa en todos los años de este estudio y/o que el comportamiento de forrajeo puede ser lo suficientemente plástico como para permitir que las aves ganen masa a pesar de las diferencias anuales en la disponibilidad de alimento.

Do Reeves make different choices? Meadow selection by spring staging Ruffs Philomachus pugnax in Southwest Friesland

Each spring Ruffs stop over in large numbers in the northern part of the Netherlands, especially in Southwest Friesland. While staging, Ruffs use meadows for feeding and refuelling. A general believe is that they are attracted by the typical Dutch wet peat grasslands, with a diverse vegetation situated in an open landscape. We wanted to test this idea and to explore whether the assumed different flyways of the sexes could be related to sexual dimorphism, e.g. whether the smaller, shorter-billed females use other habitats than the males. This paper describes which meadow characteristics are correlated with meadow use and how meadow use differs between ruffs and reeves. In April and May 2003, 125 meadows in Southwest Friesland were monitored for five weeks. The total number of Ruffs decreased over the season, which is consistent with published region-wide counts. Relatively few females passed through: only in late April, when total numbers were low, the proportion females exceeded 10%. To find correlations with meadow use, 13 scored meadow characteristics were used in a multiple logistic regression model. Grass height and distance to the nearest roost proved most important (included in the model in four weeks): used meadows were closer to a roost and had shorter vegetation than unused meadows. Vegetation type, soil type, drainage level, openness of landscape and fertilisation freshness correlated with meadow use in two or three weeks. Percent flooding, fertilisation method, presence of grazers, vegetation evenness, relief and meadow size were never included in the model. The expected reference for peat meadows was not found: sand and clay soils were used more. As expected, ‘wet’ meadows and meadows in an open landscape were used more often than heavily drained meadows or meadows near buildings or trees from where predators may launch surprise attacks. Grass monocultures were least used, but the most used vegetation type was not rich but intermediately diverse in herbs. Females seem to be more extreme in meadow choice than males: groups with females used meadows that were drained less deep (thus wetter) and situated closer to the nearest roost than meadows with male-only groups. Groups with females were also more common in peat grasslands. We found indications that the sex-related differences in meadow use may be related to differences in feeding behaviour. Females foraged with higher pacing speeds. more females than males ate insects, but females had lower intake rates. Also when eating buried prey like earthworms and leatherjackets, intake rates in females were lower, although probing rates were equal. Females likely use other flyways: the proportion of females passing through this Dutch stopover site was very low compared with an important eastern European stopover site in Ukraine. At this point we can not yet decide whether this results from a difference in habitat preference induced by the size difference between the sexes or whether competition forces the females out of preferred, rich feeding sites.