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© 2018 The Authors Nocturnal avian migration flyways remain an elusive concept, as we have largely lacked methods to map their full extent. We used the network of European weather radars to investigate nocturnal bird movements at the scale of the European flyway. We mapped the main migration directions and showed the intensity of movement across part of Europe by extracting biological information from 70 weather radar stations from northern Scandinavia to Portugal, during the autumn migration season of 2016. On average, over the 20 nights and all sites, 389 birds passed per 1 km transect per hour. The night with highest migration intensity showed an average of 1621 birds km–1 h–1 passing the radar stations, but there was considerable geographical and temporal variation in migration intensity. The highest intensity of migration was seen in central France. The overall migration directions showed strong southwest components. Migration dynamics were strongly related to synoptic wind conditions. A wind-related mass migration event occurred immediately after a change in wind conditions, but quickly diminished even when supporting winds continued to prevail. This first continental-scale study using the European network of weather radars demonstrates the wealth of information available and its potential for investigating large-scale bird movements, with consequences for ecosystem function, nutrient transfer, human and livestock health, and civil and military aviation.

Blood parasite infections have been shown to influence behavioural traits of their avian hosts, in particular activity level and boldness. Following the hypothesis that a mixed infection by different parasite species should have higher effects than single-species infections, we analysed activity and boldness in wild-caught Yellow Wagtails (Motacilla flava L., 1758), a trans-Saharan migrant, during the energetically demanding spring migration. Eighty-five percent of the birds were naturally infected with Haemoproteus Kruse, 1890 or Plasmodium Marchiafava and Celli, 1885 (Sporozoa, Haemosporida) and 27% of individuals had parasites from both genera. No differences in activity were found among uninfected, single infection, and mixed infection groups. Birds with infections from both genera appeared to be more fearful when first introduced to a cage. These birds also tended to be less likely to approach a novel object compared with uninfected birds and birds infected by a single genus only.

Orientation tests performed with Emlen funnels show much variation. This scatter in responses can be partially explained by considering the birds' personalities. We studied a Passerine migrant, the Sedge Warbler (Acrocephalus schoenobaenus), on autumn passage at Kalimok Biological Station, Bulgaria. Birds caught in the morning were kept in cages with known and regularly controlled amounts of food. In the evening they were tested for orientation, the next morning they were observed for 3 min in an unfamiliar cage, then released. Birds that ate on the first day oriented in the expected, southward direction, non-eating birds were scattered. Eating behaviour was related to the exploration pattern on the next day. Eating birds moved and flew less, hopped, looked around and explored the cage more, and were quicker in eating a food item if present. Lean birds ate and explored more but also oriented better, contrary to expectations where fat reserves indicate readiness for migration. A hypothesis is discussed where fat, migration and personality may be linked. Personality aspects may influence the individuals' ability to cope with an experimental situation and influence the outcome of the tests, therefore its analysis can help in predicting the birds' performance in apparently unrelated experiments., Orientation tests performed with Emlen funnels show much variation. This scatter in responses can be partially explained by considering the birds' personalities. We studied a Passerine migrant, the Sedge Warbler (Acrocephalus schoenobaenus), on autumn passage at Kalimok Biological Station, Bulgaria. Birds caught in the morning were kept in cages with known and regularly controlled amounts of food. In the evening they were tested for orientation, the next morning they were observed for 3 min in an unfamiliar cage, then released. Birds that ate on the first day oriented in the expected, southward direction, non-eating birds were scattered. Eating behaviour was related to the exploration pattern on the next day. Eating birds moved and flew less, hopped, looked around and explored the cage more, and were quicker in eating a food item if present. Lean birds ate and explored more but also oriented better, contrary to expectations where fat reserves indicate readiness for migration. A hypothesis is discussed where fat, migration and personality may be linked. Personality aspects may influence the individuals' ability to cope with an experimental situation and influence the outcome of the tests, therefore its analysis can help in predicting the birds' performance in apparently unrelated experiments.

Orientation tests performed with Emlen funnels show much variation. This scatter in responses can be partially explained by considering the birds' personalities. We studied a Passerine migrant, the Sedge Warbler (Acrocephalus schoenobaenus), on autumn passage at Kalimok Biological Station, Bulgaria. Birds caught in the morning were kept in cages with known and regularly controlled amounts of food. In the evening they were tested for orientation, the next morning they were observed for 3 min in an unfamiliar cage, then released. Birds that ate on the first day oriented in the expected, southward direction, non-eating birds were scattered. Eating behaviour was related to the exploration pattern on the next day. Eating birds moved and flew less, hopped, looked around and explored the cage more, and were quicker in eating a food item if present. Lean birds ate and explored more but also oriented better, contrary to expectations where fat reserves indicate readiness for migration. A hypothesis is discussed where fat, migration and personality may be linked. Personality aspects may influence the individuals' ability to cope with an experimental situation and influence the outcome of the tests, therefore its analysis can help in predicting the birds' performance in apparently unrelated experiments., Orientation tests performed with Emlen funnels show much variation. This scatter in responses can be partially explained by considering the birds' personalities. We studied a Passerine migrant, the Sedge Warbler (Acrocephalus schoenobaenus), on autumn passage at Kalimok Biological Station, Bulgaria. Birds caught in the morning were kept in cages with known and regularly controlled amounts of food. In the evening they were tested for orientation, the next morning they were observed for 3 min in an unfamiliar cage, then released. Birds that ate on the first day oriented in the expected, southward direction, non-eating birds were scattered. Eating behaviour was related to the exploration pattern on the next day. Eating birds moved and flew less, hopped, looked around and explored the cage more, and were quicker in eating a food item if present. Lean birds ate and explored more but also oriented better, contrary to expectations where fat reserves indicate readiness for migration. A hypothesis is discussed where fat, migration and personality may be linked. Personality aspects may influence the individuals' ability to cope with an experimental situation and influence the outcome of the tests, therefore its analysis can help in predicting the birds' performance in apparently unrelated experiments.