In the years 2017–2020, 104 young or adult Demoiselle Cranes ( Anthropoides virgo ) were tracked with GPS-GSM transmitters in Ukraine, Russia, and Kazakhstan. Eight flyways from different parts of the Demoiselle Crane distribution range were specified, with key areas for each flyway identified. In the European part of the range, cranes from different breeding groups followed two flyways using the same route in the fall and spring. The Azov–Black Sea breeding group wintered in Chad, while the Caspian, Volga–Ural, and Cis-Ural breeding groups spent winters in Sudan. Demoiselle Cranes from the Asian part of the range excluding the Trans-Urals carried out a circular migration. In the fall, they used six main flyways to northwestern India arriving there from the north, northeast, and east. In the spring, they flew firstly in a narrow front to the western tip of the Tien Shan Mountains, and then flew out like a fan to the north, northeast, and east. At wintering grounds and summer gatherings, gene flow can occur between cranes of different breeding groups. The migration period consisted of two stages: trophic, when cranes accumulate energy resources, and transit, when they make a long active flight without replenishing energy reserves. Fall migration took place over a short time. With migration route lengths totaling 2170 to 5600 km, the distance of the transit migration varied from 1900 to 4600 km, and their duration lasted from seven to 13 days. This is obviously a period that the Demoiselle Crane is capable of overcoming without essential replenishment of the energy costs, due to the resources accumulated before starting the transit migration. The spring migration of adults was more extended, with shorter daily flights and a longer rest at transit migratory stopovers, this probably being necessary to save energy before the breeding period. Some young cranes returned to their places of birth with their parents in the spring, while others made a transit flight to the first places of a long trophic migratory stopovers located in the southern part of the steppe zone. Some of them spend the whole summer in these territories, while others gradually move to their birthplaces, arriving 1–1.5 months later than adults do. Some young birds visit their birthplaces only after the second winter. Young birds from Transbaikalia and probably from the Altai and Khakassia made two transit flights with a long rest approximately in the middle of the flyway.

The paper presents an extended (in comparison with previous studies) analysis of the population genetic structure of a migratory wide-range species with high abundance, the Eurasian crane, Grus grus L. Using seven highly polymorphic microsatellite loci, high and very similar values of genetic diversity parameters were obtained in samples of the western ( G. g. grus ) and eastern ( G. g. lilfordi ) subspecies. Coefficients of genetic differentiation between these subspecies ( F ST = 0.008, G ST = 0.002) were also found to be low. According to AMOVA, 99% of genetic variation of G. grus is attributed to individual levels. Using the Bayesian clustering algorithm implemented in the STRUCTURE software, no clear population genetic structuring of the species was revealed. At the same time, visualization of spatial patternts of genetic variability in the Geneland software showed the presence of a cluster of “pure” subspecies of G. g. grus and G. g. lilfordi , surrounding a cluster of individuals from the zone of intergradation of these subspecies. This result, along with the observed very low F -statistics values, may indicate subtle genetic differences between the cranes from the studied area, possibly having a mutational nature. Lower allelic richness and lack of private alleles in the eastern subspecies G. g. lilfordi suggests its relative evolutionary youth and recent origin from the eastern marginal populations of the nominative western subspecies.

A captive population of the Siberian crane has existed in Russia for over 40 years, at the moment numbering 13 founders of natural origin and 17 breeders from the first and second generations, and mainly reproducing through artificial insemination. Since 2010, using molecular genetic markers, we have been monitoring the breeding and reintroduction of the Siberian crane, analyzing the genetic diversity and relationships in different generations of the population; establishing paternity in chicks obtained as a result of multiple artificial insemination; and determining the sex in individuals at different stages of their development. A total of 304 Siberian crane individuals have been genotyped by microsatellite loci. The group of breeders from the first and second generations appears still to retain the high-level heterozygosity of the founders. However, there has been a loss of allelic diversity and an increased relatedness. Paternity has been established in 135 individuals, with sex identification carried out for 225 offspring. The primary (at the time of fertilization) and secondary (at the time of hatching) ratios of males to females in the offspring of the Siberian crane in captivity have been shown to be close to 1 : 1 parity. We have completed the previously missing information on sex and paternity in the Siberian Crane International Studbook, including data on dead or released birds using specimens from the collection of allantoises. In general, in the modern livestock of first- and second-generation breeders in the captive population of the Siberian crane in Russia, high genetic diversity is maintained. Yet because of the increased relatedness and inbreeding in the offspring, the aging and natural loss of founders, and an insufficient reproductive success of young breeders, it is necessary to enrich the gene pool of this population by new birds from the wild or unrelated individuals from other breeding centers or zoos.

Using the EE0.6 molecular genetic sex marker, the gender of 155 chicks of a monogamous bird species, Demoiselle crane (Anthropoides virgo Linneaus, 1758), from the Azov-Black Sea, Caspian, Volga-Ural, Trans-Ural, Altai, Khakassian, and Transbaikal breeding groups was established. It was demonstrated that complete broods with two chicks represented by a male and a female were found more frequently than the broods with two chicks of the same sex. The broods in which both chicks were females prevailed over the broods out of two male chicks, although the differences were statistically insignificant. In total, out of 155 chicks, 69 males and 86 females were determined. Out of 112 chicks in the complete broods, 48 individuals were males and 64 were females. Despite a trend of female predominance among chicks in the total sample and in most breeding groups, the ratio of males and females in the Demoiselle crane offspring in general (0.445, P = 0.181) and in complete broods (0.429, P = 0.174) was parity, which reflects the adaptive and reproductive strategy of this monogamous bird species with a long life span.

The sex ratio of Siberian crane chicks (Grus leucogeranus Pallas) from the captive population of the Oka Crane Breeding Center was analyzed with the use of molecular sex marker EE0.6 in 2009–2014. We determined the sex of 84 birds bred from 12 dams by means of artificial insemination and natural breeding. The total primary sex ratio was 40: 44, and the secondary sex ratio was 36: 39 with a minor female bias. The mortality rate of embryos was the same for both sexes. The primary and secondary sex ratio for the first eggs in clutches were in-line with total sex ratio. The relatedness of parents by microsatellite loci has no effect on sex ratio in chicks of naturally and artificially propagating dams.

Eight variable microsatellite loci were analyzed in terms of studying the genetic structure of different generations of a captive population of a rare endemic Russian species, the Siberian crane (Grus leucogeranus Pallas). It was shown that the founding population of natural origin (15 birds) is characterized by high genetic diversity (N A = 6.625, H O = 0.767, H E = 0.731) and a lack of relatedness (R = −0.079). In the total sample of descendents of the founders (122 individuals from generations F1, F1/F2, F1/F3, F2, F2/F3), this characteristic level of genetic variation is being maintained; however, we observed a decrease in allelic richness in some generations (F1/F2, F1/F3, F2). We found a low level of relatedness in the sample of descendents of the founders (F1, F1/F2, F1/F3), while the relatedness was maximal (R = 0.302) in the descendents of the breeders of the first generation. A small sample of breeders related to each other of generations F1 and F2 (eight birds) does not represent the entire gene pool of the founders of the Siberian Crane captive population. In view of this, we discuss the need to form a new genetically heterogeneous generation of breeders that would also include Siberian Cranes from the almost extinct Western Siberian population.