When spring opens in North America, the days lengthen and warm, the flowers thrive in molten soil, and the green leaves grow on the branches. Bees are busy, and birds meet, build nests, and raise young. As any winter hard bird knows, many of these birds have spent the cold, cold northern months in the tropical southern hemisphere. Some fly thousands of miles to their breeding ground at the same place, at the same time, just like last spring and earlier spring.
Why do birds make these seasonal trips? But first, how bird migration has improved is, in fact, a topic that has long been debated by scientists.
Researchers do not know much about ancient birds and their relatives millions of years ago to determine when the first bird ancestors migrated. Existing evidence goes back hundreds of thousands of years. Genetic studies, for example, show that the Galapagos Hawks differed from the Swansen Hawks 125,000 to 250,000 years ago. However, it is not yet possible to monitor bird migration in time. In fact, bird migration may be much older.
Robert Zinc, an evolutionary biologist at the University of Nebraska, says: Various species, such as squid, butterflies, and deer, have improved migration characteristics, Zinc says, suggesting that migration is a fundamental response to the use of modern resources. In other words, birds can be even more amazing if they do not migrate.
For decades, the debate over how birds migrated for the first time has revolved around hypotheses about the “southern house” and the “northern house.” These ideas basically suggest that modern immigrant species originally lived in either tropical (southern) or tropical (northern habitat) and gradually evolved between the two climates to use food, escape competition, or breed in places. With relatively small predators. Refugees come from all walks of life, and the birds of prey prosper, reproduce, and pass on to the next generation.
In recent years, some researchers have viewed migration as slightly different. Exploring the evolutionary link between the species and exploring modern reproductive biology, archaeologist Benjamin Winger argues that migration is closely linked to the seasons – the latitude of any geographical origin or species.
“The fact is, birds are everywhere and they are adapting to their current situation,” said Wingger, who studied Avian migration and dispersal at the University of Michigan. According to this view, birds migrate in order to escape life-threatening environments – not much different from bear sleep or insect infestation. “To live in these heights, [birds] He must be a refugee. ” (Evolution always offers special conditions. Ptarmigans, which are buried in the winter, are among the few birds that live throughout the North latitude).
Prepared in this way, flying south to escape the winter – when there is little food – is just one example of why birds migrate. The theory also applies to birds migrating up and down, or in tropical areas, to follow current rainfall, temperature, and other environmental conditions.
Of course, escaping difficult situations may not be the complete story of migration: “This difficult part is explaining why they will return next year,” says Wingger. To this end, birds – like many creatures – prefer to be in their place of birth. “The key is to get them back to normal,” he said.
Bird migration may be related to breeding patterns. According to Wingger’s work, a long-distance refugee like Swainson Turus produces fewer offspring than Hermith Turus, which does not travel much. Surprisingly, despite the difficult journeys of adult Swanson Trush, they have a better chance of survival. The same evolutionary process between producing a few surviving offspring can be seen all over the animal world, like an elephant, or many children dying prematurely, like rats. This information shows that long-distance Avians can be likened to an elephant rather than a mouse. “Basically, migration encourages this high survival, low reproductive output strategy,” Wingger said.
According to Christine Rug, a researcher at Colorado State University and director of the Bird Genoscope Project, migration is at an all-time high, but modern migration is at least partially genetic. In breeding experiments, for example, scientists breed a bird (like the Eurasian blackcup) that migrates long distances in one direction with another bird (such as the Eurasian blackcup). Permanently, the seeds try to migrate at medium distances and in the middle direction.
These results show that migration patterns can be passed on or improved by generation. But figuring out which specific genes are responsible is “harder than you think,” Rug says.
Avian researchers also want to better understand how genes are registered for migration. All animals have internal clocks that respond to environmental signals such as light, heat, or stress. These watches, for example, are responsible for the circadian rhythms that people practice in a 24-hour cycle. Unlocking the genetic material that controls these clocks in birds can shed light on how and why migration occurs.
Other genetic questions remain. For example, not all birds migrate. Scientists still think that these species have all those genes but that they are extinct. But that is not the case, says Winger.
Another important question during rapid climate change and climate change is that the characteristics that can be passed from generation to generation can be rapidly improved. The fact that birds in North America have adapted to the growth and decline of glaciers over the past several million years is a sign that migration behavior is changing, says Zinc. Researchers at Eurasian Blackcaps and House Finches have even documented the development of new migration patterns in just a few generations. This does not mean that all birds can adjust. Very quickly.
Much of the research is academic and nude. And with millions of birds flying this spring, it may seem impossible for ordinary observers to meditate on them. But it is important to remember that birds are not so amazing – they can easily survive.