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The work is aimed at determining the onset of breeding in the White-tailed Eagle and the reasons that affect its breeding phenology in the central part of the Volga-Kama region (the Republic of Tatarstan, together with the adjacent areas of the republics of Chuvashia and Udmurtia, as well as the Samara and Ulyanovsk regions). In the Republic of Tatarstan, the main data was obtained in 2011-2016, in the Ulyanovsk and Samara regions in 2012, in the Republic of Chuvashia in 2013, 2015, 2016, and in Udmurtia in 2016. An analysis of the onset of breeding was carried out based on photo records of White-tailed Eagle nests with nestlings aged primarily 30-60 days, some less than 30 days, in 2011-2016. The age of nestlings was further defined by the photo tables comparing the degree of development of the plumage. The date of the first egg laying was set taking into account the age of the older (or a single) nestling and the incubation time which was 37 days. In total, 119 cases of breeding were analyzed. For additional control of calculations concerning the earlier periods of breeding, at the beginning of the breeding season, on 23.02.2015, distant observations of a group of 16 nests were carried out using optical devices at the upper reaches of the Kuibyshev Reservoir. More precise data on the terms of egg laying were also obtained using a surveillance camera at an eagle nest in the Volga-Kama Biosphere Nature Reserve. According to the results of calculations, the period of the first egg laying extends from February 22 to April 11 (n = 119). Most of the clutches (70.6%, n= 84) are laid in the period from February 22 to March 15, the maximum in the first 5 days of March (26.05%, n= 31). A comparison with previously published data shows that on average the eagles start breeding half a month earlier than they did in the 20th century. In our opinion, the shift towards earlier terms was primarily related to changes in the nature of eagles' habitat under the influence of an anthropogenic factor of feeding at wintering sites and increased species numbers in the Volga-Kama region. The eagles started partially settling. The distances of their flights from nests in search of food shortened during the winter period. The influence of climate warming on the time of egg-laying cannot be excluded either.