Robins' Migratory Journey
You may have heard about the long-distance migratory abilities of birds, and among them, the Eurasian Robin, widely distributed across Eurasia, has caught the attention of scientists.
The robin is a small songbird and is a favorite among the British people. In the British lexicon, home is synonymous with the robin. Wherever the British settle, they always yearn for the endearing robin.
They have a habit of labeling various species of birds, with diverse appearances but generally resembling robins, as robins, which brings them a constant sense of satisfaction, as if surrounded by adorable angels. Some of them fly south to the Iberian Peninsula for the winter, making it ideal for scientists to study bird migration and orientation mechanisms.
Every March, when the beautiful spring arrives, flocks of robins emerge from palm and avocado groves in various states around the Gulf of Mexico and migrate northward. Batch after batch, for several weeks, totaling over a billion, they flow over the sky above the Mississippi River like dark clouds.
Then they split into two routes: the western route follows the Missouri River northward, crossing plains, the Rocky Mountains, and Canada, all the way to Alaska; the eastern route follows the Ohio River northeastward, all the way into Canada.
Sometimes, if the temperature drops sharply along the way, the robins will retreat to warmer areas temporarily. They travel about thirty to fifty kilometers each day, occasionally stopping in fields to feed on insects. Most robins reside year-round, but a small number of females migrate south for the winter, even as far as Spain.
After breeding in the north, the robins return in winter to the south in grand fashion. During migration, robins always fly during the day, being the earliest risers and the last to sing their "nightly serenade."
There have been two main theories about how migratory birds perceive the magnetic field. One theory suggests that cells in the birds' beaks can sense the Earth's magnetic field and transmit this information to the brain through the nervous system. The other theory suggests that light-sensitive cells in the birds' eyes can "see" the magnetic field and transmit information to a region in the brain called the "N cluster" through another pathway.
In October 2009, to pinpoint the exact location of the "biological compass" within migratory birds, Dr. Henrik Mouritsen's research team at the University of Oldenburg in Germany studied 36 European robins that could accurately orient themselves in both natural and laboratory environments. Dr. Mouritsen suggested that a special protein in the robins' eyes called "cryptochrome" might be the medium for this light-dependent magnetic field sensing.
Stimulation by light causes this protein to produce a pair of free radicals, and the unique properties of the electrons carried by these radicals may enable them to sense the Earth's magnetic field. This research was published in the British journal Nature on October 29, 2009.
Scientific research has confirmed that the eyes of Eurasian robins can "see" the Earth's magnetic field, guiding them during migration. Understanding the navigation principles of migratory birds is of great importance for their protection. Migratory birds relocated by humans often fly back to their original habitats. If researchers can figure out how they navigate, conservationists can devise ways to "trick" the birds into staying in safe areas.
Perhaps the British inherently possess a romantic gene, as they habitually appreciate their surroundings with eyes of beauty, adding many unique elements to the robin and creating songs, stories, novels, and more about robins, enriching their image.