First arrival dates of the Nightingale (Luscinia megarhynchos) to Central Croatia in the early 20th century and at the turn of the 21st century

Global climate change has important impacts on animal life-cycles. One of the responses to global warming is an earlier arrival time of many migratory bird species. The first arrival date of the Nightingale (Luscinia megarhynchos) in Central Croatia was studied for the periods of 1901–1917 and 1991–2005. Data were derived from the first spring observations and first capture data. A statistically significant advance of 11 ± 1.4 days was recorded. The difference in the mean April temperature between two study periods was significant, while changes in NAO winter index were not significant. Adequate data from the beginning of the 20th century exist; however, recent studies were done on a relatively short-term basis. Therefore, the analysis of two discrete datasets may help to fill the gaps in the knowledge about the climate change response.