An offered article is about the deep study of life and scientific activity of the well known Ukrainian scientist-ornithologist, theriologist and urboecozoologist Mykola Ivanovych Gavrylenko (1889-1971), native of Poltava, who made a significant contribution to the development of Ukrainian natural science. He had to re-enter the difficult socio-cultural space before the German-Soviet war after the exile, to find his place in it and rejoin the continuation of the study of the Poltava region nature, restoring the lost scientific connections and finding a job. The person is purposeful and consistent, the scientist who overcame difficulties and began to self-realization in the following areas later: teaching practical and field classes with students at a local pedagogical institute; further conducting his own field of researches and fixing the results; the final creation of the ornithological collection, that was unique in terms of quantitative and qualitative indicators of available materials, the actual content is unique. A separate hypostasis of scientist became service to the museum of his native land and particularly the Poltava regional museum. Work with students positively influenced on a scientist, with joy and great desire and responsibility at the same time, he passed his knowledge on his lectures, both acquired at Kharkiv University (1912-1916) and those that he personally produced as a result of long periods of observation in nature. The scientist gave special value to realization the practice with students in the field terms, that woke up and maintained interest in learning about the nature around them in future. His grateful students left memoirs, emphasizing the best traits of their Master. Many of them chose the path to science later. Scientist conducted his own field researches during the field practices with students, but gave advantage to the separate own exits or journeys for a few days to different parts of Poltava region, aiming to study birds in their natural environment. The results were a generalization of the observings with next promulgation. In addition, the scientist using their methodology, obtained materials in nature for addition to the ornithological collection (he made the carcasses of birds). Unique collection of bird carcasses is in the Museum of Nature of KhNU named by V.N. Karazin now.

Life and scientific activity of scientist M.I. Gavrilenko is not only deserving imitation, it is an example of how one gifted person made a significant contribution to the birds studying in Poltava region, their place in the ornithological complex of Ukraine with a projection the bird population of the former USSR.

1. Atemasova T.A., Krivizkii I.A. (1999) Ornitologi Ukrainy. [Ornithologists of Ukraine]. Bibliographic reference. IN 1. Kharkov. 286. [in Russian]
2. Boiko P. (November 25, 1944). Vidnovliuiutsia muzei Poltavshchyny. [Museums of Poltava region are being restored]. Star of Poltava region. p 4. [in Ukrainian]
3. Dementiev G.P. (1940). Petr Petrovich Sushkin: pochetnyj chlen Mosk. o-va ispytatelej priroda. [Petr Petrovich Sushkin: honorary member of Moscow nature testers]. Moskva, MOIP. 22. [in Russian]
4. Havrylenko M. (1946). Novi vydy zviriv ta ptakhiv i yikh biolohiia.[New species of animals and birds and their biology]. Scientific notes of Poltava State Pedagogical Institute: anniversary edition of 1921-1946. Vol. 6. Poltava. pp 121-129. [in Ukrainian]
5. Havrilenko N.I. (1970). Pozvonochnye zhivotnye i urbanizaciya ih v usloviyah goroda Poltavy. [Vertebrate animals and their urbanization in the conditions of the city of Poltava]. Kharkov: KhSU Publishing House. 138.[in Russian]
6. Mazyrmovich B.N. (1983). Aleksandr Mihajlovich Nikolskij (nauchno-biograficheskaya seriya). [Alexander Mikhailovich Nikolsky (scientific and biographical series)]. Moskva: Nauka.80. [in Russian]
7. Piskova E.M.. Editor: Smolii V.A.(2011). Entsyklopediia istorii Ukrainy: u 10 t. [Encyclopedia of the History of Ukraine: in 10 volumes]. Poltava Museum of Local Lore. Pa-Prik. 372, p 520. [in Ukrainian]
8. Rotach P. (2004). Havrylenko M.I. (1889-1971). Materialy do biohrafii vidomoho vchenoho-ornitoloha, kraieznavtsia i pedahoha. [Havrilenko M.I. (1889-1971). Materials for the biography of the famous ornithologist, local historian and teacher ]. Poltava: Verstka. 86. [in Ukrainian]
9. Samorodov M.V., Kyhym S.L. Scientific editor: Hrynova M.V. (2009). Pryrodoznavets Mykola Havrylenko epokha ta pamiat. [Naturalist Mykola Havrylenko, epoch and memory]. Poltava. 203, p 70, il. [in Ukrainian]
10. Sharleman M.V. (1938). Ptakhy URSR (materialy do fauny). [Birds of the USSR (materials for fauna)]. Kyiv, AN USSR. 266. [in Ukrainian]