Every since grade school I pretty much understood, or thought that I understood everything about birds and their migrating process. And I think that my understanding was basically the same for a lot of other people. Birds migrate to somewhere warmer during the colder seasons of that particular region. I never really thought about the “why” to the migrating process, I just knew that it happened.
I’m a simple guy so the explanation was basic for me. Since I’m not crazy about cold weather and if I live outdoors, why would I stay somewhere that’s cold? I would just go to a warmer climate so that I could be comfortable while I eat and sleep outside. With further investigation though, it didn’t take me long to realize that my thought process was limited and came from my current reality of not having to actually live a life that’s exclusively outdoors and that I didn’t have to hunt for my food.
Migration is, of course, a seasonal event and of the birds that do it, they migrate mainly because a lot of the “food” that they regularly partake of isn’t available during the colder months. Of course, many birds aren’t built for extremely cold weather and would more than likely die if exposed too long to the cold but the main reason for their migration process is because their main food sources don’t do well in the cold either. So, its necessary that some birds migrate in order to survive. Where there is an abundance of their food source, birds are able to carry on with the natural order of things like mating and reproducing.
If you notice, I subtly mentioned that not all birds migrate. Most do, but these birds don’t: northern mockingbird, grouse, gray jay, ptarmigan, common raven, quail species, Townsend’s solitaire, a lot of the owl species, Carolina wren, pileated woodpeckers, white-breasted nuthatch, hairy woodpeckers, red-bellied woodpeckers, and downy woodpeckers. These birds are adaptive to their regions and will survive off of what the land provides for them during the colder season.
Bird migration is a seasonal event that usually patterns north to south movements. These north to south movements of the birds happen along what is called a flyway. A flyway is just a general term for the path that birds take when they are migrating. A flyway can span over continents and even oceans.
Migration for birds comes with serious drawbacks… the main drawback being preyed on by birds of prey and by humans as well. Along with this, because they often travel really long distances, birds become easier prey simply out of sheer exhaustion. Nature has it to where certain types of birds of prey will have their breeding season during this migration time so that they can feed their young the migrating birds.
Of the birds that migrate, there are two types that I found to be interesting. The arctic tern is one of those birds and is considered to be strongly migratory. Here’s what I mean. The arctic tern is a seabird and migrates from its northern breeding grounds to the Antarctic coast for the southern summer and then six months later it goes back again, usually seeing two summers. Studies have been done on the Arctic Tern and they have shown that the annual round trip for birds nesting in Iceland and Greenland is about 44,100 miles and 56,000 miles for those that nest in the Netherlands. It nests once every 1 to 3 years but most of its lifespan is spent flying, making its long southern migration.
The bar headed goose is another migrating bird that I found to be interesting. Why? Well, because it is considered to be the world’s highest flying bird. It breeds in large colonies in Central Asia near mountain lakes and winters in South Asia. When its time for them to migrate these geese will take their path over the highest mountain range in the world, the Himalayas. Its has been reported that some of the geese were tagged and it was shown that some of the geese got up to heights of 18,000 ft. They travel from lowland India to breed in the Tibetan plateaus and will make the 7 hour flight straight through if the weather conditions are right. If conditions aren’t right, they will turn around and attempt the marvelous journey gain the next day.