Ever wondered how without the help of a map and modern transportation different species of birds manage annual round-trip migrations going on thousands of miles from year to year?
Nature indeed is amazing!
For birds, migration means two-way journeys—an onward journey from the ‘home’ to the ‘new’ places and a return journey from the ‘new’ places to the ‘home’. This movement occurs during a particular period of the year and the birds usually follow the same route -using some sort of ‘internal biological clock’ which regulates the phenomenon.
Why Do Birds Migrate?
Birds migrate to move from areas of low or decreasing resources to areas of high or increasing resources. The two primary resources being sought are food and nesting locations. Escaping the cold is a motivating factor but many species, including hummingbirds, can withstand freezing temperatures as long as an adequate supply of food is available.
Of course, not all birds migrate. Some species have adapted to take advantage of different food sources as seasons change, allowing them to stay in one location all year round. For more than half the world’s birds, however, migration is essential to their survival.
One of the greatest mysteries of migration is exactly how birds find their way from one location to the next. Scientific studies have been done on a number of bird species, and several different techniques of bird navigation have been discovered.
- Magnetic Sensing: Many birds have special chemicals or compounds in their brains, eyes, or bills that help them sense the Earth’s magnetic field and orient themselves in the right direction for long journeys, just like an internal compass.
- Geographic Mapping: Because birds follow the same migration routes from year to year, their keen eyesight allows them to map their journey, from landforms and geographic features such as rivers, coastlines, canyons, and mountain ranges helping to keep birds heading in the right direction.
- Star Orientation: For birds that migrate at night, star positions and the orientation of constellations can provide necessary navigation directions. During the day, birds also use the sun to navigate.
- Learned Routes: Some bird species, such as sandhill cranes and snow geese, learn migration routes from their parents and other adult birds in the flock. Once learned, younger birds can travel the route successfully themselves.
Are humans messing with these birds ‘migratory know-how?
Studies show that humans may be making it harder for birds that migrate and find their way because humans are scrambling the magnetic field through electrical equipment, radio towers, and other technologies. The effects of these weak electromagnetic fields are remarkable: They disrupt the functioning of their entire sensory system.
Other migratory mishaps include; Inadequate food and subsequent starvation, collisions with windows, buildings, power lines, and wind farms along migration routes, predators, including wild animals, feral cats, and loose dogs, poor weather and storms that cause injury or disorientation, light pollution in cities that disorients birds navigating by stars, hunting, both legal regulated hunting as well as poaching among others.
What can you do to help?
- Turn off all non-essential lights from 11 p.m. to sunrise.
- Support the laws that migratory birds can’t live without.
- Protect birds from cats.
- Reduce your plastic footprints.
- Support groups that are making birding more inclusive
Do you have any question or comment? Do share with us in the comment section.