The Migration of the Eurasian Woodcock (Scolopax rusticola L.) in the Carpathian Basin at the Turn of the 19–20th Centuries.

Simple Summary: There are few data sets in bird migration research that go back more than a century. The Carpathian Basin is one of the exceptions, where spring return data for migratory birds were intensively collected and published between 1894 and 1926. One of the most numerous records was that of the Eurasian Woodcock, which provided an opportunity to study the timing of migration of the species and the influence of different environmental and geographical factors on migration. In years with snowier and colder weather, birds returned later than in years with milder weather. The migration occurred earlier in lowlands than in mountain and hill areas. Food availability played a key role in explaining the differences between years and geographical regions. We also showed a two week difference in arrival time between southwestern and northeastern regions. It is likely that climate change is now causing the species to migrate much earlier, but the extent of this cannot be accurately determined without comparison with recent data. In the present study, 7344 spring observations of a short-distance migratory species, the Eurasian Woodcock, from the Carpathian Basin between 1894 and 1926 were used to investigate the timing of the species' migration and how different environmental factors influenced it. We used a generalized additive model (GAM) to explore migratory patterns by using environmental and geographical variables. In years when the weather was colder and snowier, the birds migrated weeks later than in years with milder weather. This may be due to the availability of earthworms, which are the most important food for the species. In areas at lower altitudes, migration occurred earlier than in mountainous areas, which may also be due to the different weather. Furthermore, a two week difference was observed between the south-western and north-eastern parts of the Carpathian Basin. This difference is still present nowadays, but the timing of migration has shifted earlier than in the past, probably due to climate change. It would also be important to compare the historical data with recent data to gain a better understanding of the effects of climate change on the migration of the Eurasian Woodcock. [ABSTRACT FROM AUTHOR]