Genomics and Applied Biology 2024, Vol.15, No.1, 1-7 http://bioscipublisher.com/index.php/gab 2 1 Bird Migration and Genetic Diversity 1.1 Overview of bird migration The migration of birds is a miracle of life, performing magnificent rhythms in the changing seasons. They cross the sky, from south to north, from east to west, carrying the wonders of the ecosystem on their migration journey. The ancient migration tradition is not only an instinct of birds, but also a key factor in ecological balance. However, as the climate continues to change, this magnificent migration faces many challenges. Bird migration varies in scale and distance. Some birds only migrate for short distances within relatively localized areas, while others migrate for long distances across thousands of miles, continents, and even ocean currents. These movements are not accidental, they are closely related to seasonal climate change. Environmental factors such as temperature, light, and wind play important roles in bird migration. The changes in these factors will directly affect the feeding locations, breeding areas, and overall migration paths of birds. Migration is not only related to seasonal environmental changes, but also closely related to reproductive cycles, reproductive behavior, and foraging habits. During the migration process, birds require a large amount of energy to support long flights, and many birds need to search for food to maintain their physical strength during the migration. Therefore, the smooth progress of migration is crucial for the survival and reproduction of birds (Morganti, 2015). The migration of birds covers a wide range of species and regions, and the migration patterns and scales of each bird species vary (Table 1). For example, the Red billed Quelea exhibits billions of swarms on the African savannah, exhibiting astonishing large-scale swarm migration; The Arctic tern, on the other hand, has the longest migration route in the world, spanning tens of thousands of miles within a year, crossing the poles of the entire Earth. These migrations of different scales and distances not only vary in itinerary, but also directly affect the genetic diversity of bird populations. Table 1 Representative migratory bird information (Xu et al., 2021) The order, family, and genus of migratory birds Representative types Distribution location Migration distance Craniformes, crane family, white crane genus Grus leucogeranus Distributed mostly in Eurasia and Africa 8 000 kilometers Chariotiformes, gull family, tern genus Sterna paradisaea Distributed near the Arctic 70 00 kilometers Storyliformes, Egret family, Egret genus Egretta garzetta Distributed mostly in Africa, Madagascar, and Eurasia 900 kilometers Falcons, family Falconidae, genus Falcon Falco peregrinus Distributed mostly near the Arctic Circle 6 400 kilometers Passeriformes, family Orioles, genus Orioles Phylloscopus trochilus yakutensis Distributed mostly near Siberia 13 000 kilometers The different patterns and scales of bird migration have varying degrees of impact on genetic diversity. In small-scale migration, the genetic relationships of the population may be closer, and the flow of genetic information during the migration process is relatively limited. In contrast, birds that migrate over long distances globally may experience more extensive gene flow, and populations from different regions may exchange genetic information more frequently, thereby affecting the genetic diversity and structure of the population. Therefore, understanding and studying the impact of migration of different scales and distances on gene diversity is crucial for comprehensively grasping the genetic characteristics of bird ecosystems. 1.2 The concept of genetic diversity Genetic diversity refers to the degree of diversity in genotype and gene frequency within a specific species or population. It involves the differences in individual genes within a population, including genotype diversity, changes in gene frequency, and the magnitude of genetic variation. In the context of bird migration, genetic diversity focuses on the differences between individual genes within a population, which directly relates to the adaptability of the population to environmental changes.
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