Has recent climate warming affected the dates of bird arrival to the Il℉men Reserve in the Southern Urals?

The results of regression and correlation analyses of long-term data (1971–2005) on the dates of arrival of 16 bird species to the Il’men State Nature Reserve (the Southern Urals) show that they have not changed in most of these birds, unlike in many countries of Europe and North America. This is explained primarily by the absence of any significant trends in the dynamics of spring air temperatures in the study region. Only the herring gull Larus argentatus and the lapwing Vanellus vanellus have shown a significant tendency to arrive earlier, while the garganey Anas querquedula has shown a tendency to arrive on later dates in the past two decades. Nevertheless, interannual fluctuations in the dates of arrival are well manifested in both early arriving species wintering in Europe and late-arriving species wintering in Africa. These fluctuations largely depend on temperature conditions in spring. As a rule, almost all species studied—from waterbirds to passerines—appear in the Il’men Reserve earlier in years with early and warm springs than in cold years. Hence, spring weather is the key factor determining the dates of arrival of migratory birds to the study region.