According to whether migratory birds can be divided into migratory birds and resident birds. In fact, migratory birds and resident birds are only relative concepts, and there is no unbridgeable gulf between the two, but they can be transformed into each other.
Of course, some resident birds do not have the ability to migrate long distances and it is not easy to become migratory birds, but migratory birds only need the right timing and location to become resident birds.
Birds will adjust their habits according to different natural environments, and with the right habitat, some migratory birds may stay in a certain place for a long time, even eventually changing their migration habits for thousands of years. In the Black Stork Nature Reserve in Lingqiu County, Shanxi Province, there are migratory birds that become resident birds. Black storks are typical migratory birds that originally fly to the south for the winter, but since 2008, a considerable number of them have been breeding locally in Lingqiu and overwintering in the area, becoming resident birds.
According to experts' analysis, the reasons for migratory birds becoming resident birds include climate and food.
The Max Planck Institute in Germany found that climate warming is making the migration distance of some migratory birds gradually become shorter, and they may even become non-migratory resident birds within a few generations; some migratory birds that have just bred offspring have lost their migration ability and become resident birds.
At the same time, the living environment of birds is gradually becoming better. For a long time, China has been actively promoting the protection of birds, strengthening the protection of bird habitats and migratory resting places and maintaining the population source of bird species by establishing nature reserves and implementing endangered bird protection projects. The Wildlife Protection Law incorporates migratory bird habitats and migration pathways into the scope of legal protection, making migratory bird breeding sites, wintering grounds, resting places and migration pathways the main objects of protection in nature reserves. Through the establishment of nature reserves, the ecological environment of bird habitats and migratory resting places has been changed, so that the bird resources and migratory birds in China are effectively protected.
Today, China's continuously improving ecological environment can provide better habitat and feeding conditions for migratory birds, and there are more and more areas that meet the conditions for migratory birds to rest. In addition, people's awareness of bird care and protection has increased, fewer people are catching birds and hurting them, and birds have a greater sense of security. Well fed and well housed, so many migratory birds have become resident birds.