Az erdei szalonka (Scolopax rusticola L.) vonulása a XIX–XX. század fordulóján a Kárpát-medencében

The timing of spring migration has changed significantly for many bird species over the last century. This is particularly true for short-distance migrants, where there is a difference in return times of up to months compared to previous decades. In our study, we sought to answer the question of what geographic and environmental factors influenced the timing of spring migration of Eurasian Woodcock at the turn of the 19th and 20th centuries. We used 7344 observation data from the Carpathian Basin from the period between 1894 and 1926, collected by members of the contemporary bird-watching network and published as annual reports in the journal Aquila. Generalised Additive Model (GAM) was used to answer this question. Our results show that in years with colder and snowier weather, birds migrated significantly later than in years with temperate weather. This is likely to be due to the availability of earthworms, which are the species’ main food source. In lower altitude areas, migration was earlier than in higher areas, also due to the different weather conditions. In addition, we found a two-week difference between the southwestern and northeastern parts of the Carpathian Basin. The difference persists nowadays, however, the birds arrive earlier than in the past. The most porbably reason for this is the global climate change. However, to examine the impact of this on the migration of the species, historical data should be compared with recent data.