The success of Eagle Owl breeding in artificial niches and natural nests was studied. Manufacturing and installing artificial nests for Eagle Owls in Mordovia, central European Russia is employed as a factor to increasing the number of both successfully breeding pairs and the population size. At the same time, no differences were found for artificial and natural nests in terms of reproductive success, clutch size, and the number of fledglings. In 51% of nesting cases, pairs laid three eggs, compared to two eggs in 43% or four eggs or one egg each in 3%. The average clutch size was 2.54 ± 0.08 eggs. Over the years of our study of owl nesting in Mordovia, 13.6% pairs raised one chick, compared to two and three chicks in 36.4 and 50%, respectively. The number of reared chicks per successful nest averaged 2.36 ± 0.11. The mortality rate in nests was lower in artificial nesting sites (30%) than in natural ones (40.6%).
Lapshin A., Andreychev A., Alpeev M., Kuznetsov V. Breeding success of the Eurasian Eagle Owl (Bubo bubo, Strigiformes, Strigidae) in artificial nests // Biology Bulletin. 2023. V. 50. № 7. P. 1486–1492.

A new method and new techniques are proposed for making artificial nests for Eagle-owls to increase their population. Artificial nesting sites allow Eagle-owls to hatch their chicks successfully and stay in a certain area. The results of field studies show that one of the decisive factors for large owls is the presence of a nesting site protected from both bad weather conditions and humans. This method has been tested under conditions of the forest–steppe zone of the Volga region. According to our observations, a special roof and special walls for artificial nesting protect the nest from adverse weather conditions and shedding.
Lapshin A., Andreychev A., Alpeev M., Kuznetsov V. Techniques for making artificial nests for Eagle-Owls (Bubo bubo, Strigiformes, Strigidae) to increase their population // Biology Bulletin. 2022. V. 49. № 9. P. 1503–1507.

Small mammals are important reservoirs for zoonotic pathogens that cause significant morbidity in humans. Of these, tularemia and hemorrhagic fever with renal syndrome (HFRS) are among of the most widespread zoonotic diseases worldwide. Despite the fact that both pathogens have great epidemiological significance in Russia, epizootological data for urbanized areas are still scarce. This study was conducted to investigate the occurrence and prevalence of tularemia and hantaviruses in small mammals living in close proximity to humans. Altogether, 425 small mammals (278 from urban environment and 147 from natural environment) representing nine species (Myodes glareolus, Microtus arvalis, Cricetus cricetus, Apodemus flavicollis, Apodemus agrarius, Apodemus uralensis, Mus musculus, Sorex araneus and Neomys fodiens) were captured in the Russian Republic of Mordovia and screened for pathogens using different serological and bacteriological methods. Red bank vole (M. glareolus) and yellow-necked wood mouse (A. flavicollis) are among species in the forest zone of the city of Saransk and are the source of a number of zoonotic diseases. In the non-urban environment, the main role as carriers of zoonotic diseases was played by house (M. musculus) and striped field (A. agrarius) mice. A total of 23 % of the small mammals sampled in Saransk were positive for tularemia, whereas 9.7 % were positive for HFRS. Furthermore, dual infections with both tularemia and hantaviruses were shown in 1.4 % of animals, suggesting that the same small mammal host can be infected with several pathogens at the same time, therefore representing a serious threat to public health. Small mammal ecology is a primary determinant of zoonotic pathogens dynamics in rodent populations and the risk of pathogen transmission to people.
Maydanov, M., Andreychev, A., Boyarova, E., Kuznetsov, V., & Ilykaeva, E. SMALL MAMMALS AS RESERVOIRS OF TULAREMIA AND HFRS IN THE FOREST ZONE OF SARANSK. Forestry Ideas. 2021. V. 27. № 1. P. 128–135

A list of 40 species is presented of the rodents and insectivores collected during a 15-year period from the Republic of Mordovia. The dataset contains more than 24,000 records of rodent and insectivore species from 23 districts, including Saransk. A major part of the data set was obtained during expedition research and at the biological station. The work is based on the materials of our surveys of rodents and insectivo-rous mammals conducted in Mordovia using both trap lines and pitfall arrays using traditional methods.
Andreychev A., Kuznetsov V. Checklist of rodents and insectivores of the Mordovia, Russia // ZooKeys. 2020. № 1004. P. 129–139.

Republic of Mordovia in Russia is a historical focus for hemorrhagic fever with renal syndrome and tularemia. This study aimed at assessing the current status of these foci by studying their rodent reservoirs. Among the small rodents in Mordovia, the red bank vole, the common vole and the house mouse play an important role as carriers of zoonotic diseases. However, it is necessary to take into account the role of such а small species as forest dormouse (Dryomys nitedula), which has a high percentage of infection. Of all examined dormice, 66.7 % were found to have antigens of hemorrhagic fever with renal syndrome viral pathogen, and 33.3 % - to have antigens of tularemia pathogen. Only one specimen (16.7 %) was found to have no antigens of zoonotic diseases. Our study concluded that the forest dormouse in the Republic of Mordovia was incriminated as a pathogen reservoir causing infectious diseases in human
Andreychev A., Boyarova E. Forest dormouse (Dryomys nitedula, Rodentia, Gliridae) - a highly contagious rodent in relation to zoonotic diseases // Forestry Ideas. 2020. V. 26. № 1. P. 262–269.

The activity of the greater mole-rat was studied using a new technique. New data have been obtained on the characteristics of the daily and seasonal underground life of mole-rats in an isolated population in Mordovia. Polyphase daily activity is most pronounced in the spring and early fall periods. In spring, the maximum activity (about 20% of all daily registrations in separate hours) is confined to the periods from 8:00 to 9:00 a.m. and from 3:00 to 4:00 p.m. The peak of activity in the early fall was recorded from 9:00 to 10:00 a.m. At night, the activity of animals in different seasons was stably low. The burrowing activity, as a rule, began after midnight and stopped in the morning before 5:00 a.m. The maximum duration of the dormancy period in the evening in summer months was five hours. Statistically significant differences were obtained for the average number of passages of mole-rats in the burrow per day for different months using the Mann‒Whitney criterion (p < 0.05).
Andreychev A.V. Daily and seasonal feeding activity of the greater mole-rat (Spalax microphtalmus, Rodentia, Spalacidae) // Biology Bulletin. 2019. V. 46. № 9. P. 1172–1181.

В работе представлены результаты многолетних исследований видового состава растений Мордовии с целью выявления кормовых видов степного сурка. Установлено, что кормовая база представлена 105 видами из различных семейств. Наибольшее значение в рационе питания имеют растения из семейств Сложноцветные (Compositae) (27 видов), Злаки (Gramineae) (23 вида), Бобовые (Leguminosae) (16 видов). Среди кормовых видов растений по экологической градации в отношении воды на всех участках колоний преобладали представители группы мезоксерофитов. Мезофитные формы уступают мезоксерофитам. При распределении поедаемых сурками растений выяснено, что большинство из них (от 91,9 до 94,2%) относятся к светолюбивым. Анализ видов кормовых растений, произрастающих на разных участках колоний, по составу жизненных форм выявил преобладание многолетних трав (от 74,3 до 79,1%).
Жалилов А.Б., Силаева Т.Б., Андрейчев А.В. Результаты изучения кормовой базы степного сурка (Marmota bobak) в Республике Мордовия // Вестник Оренбургского государственного педагогического университета. 2016. № 2 (18). С. 19–26.

Приводится оценка численности и плотности населения средних и крупных млекопитающих на примере одного из районов Мордовии. Характеризуется динамика численности охотничьих видов и даётся прогноз её оптимально возможной величины при соблюдении комплекса биотехнических мероприятий.
Жалилов А.Б., Андрейчев А.В., Кузнецов В.А. К мониторингу и сохранению средних и крупных млекопитающих Чамзинского района Республики Мордовия // Вестник Нижегородского университета им. Н.И. Лобачевского, 2014. № 4 (1). С. 222–227.