Source: Greeley Tribune
There are around 30 million birders in the United States watching an estimated 700 species that live or migrate here from the south. In this article, I am throwing out a lot of numbers and still hoping I can show the uneven distribution of birds on our planet and some of the reasons why scientists believe this is so.
We have 7 percent of the almost 10,000 birds identified in the world, encouraging avid birders who want to increase their birding list number to travel the world to see the other 93 percent. For some reason unknown to man, the birds are more colorful where there is more food and energy from the sun. South America is the continent with the most birds, with tropical Ecuador boasting 1,500 species, twice the amount of U.S., which has 30 times the land mass. There are patterns in the geographic location of birds. For instance the North Pole and the South Pole have few species. The trend is reflected in other animals such as insects and lizards. Brazil has 222 species of ants as compared to Alaska’s seven. Brazil also has 2,500 freshwater fish, Central America has 500 and 170 in the Great Lakes. Tiny Costa Rica has 600 breeding birds, southern Mexico has 400, with 200 breeding birds in northern Mexico, 190 in the North Pacific and 100 in Alaska and Canada. Note the decline in breeding numbers as we travel away from the equator.
What is the reason for the species diminishing in numbers as we move away for the equator? Scientists are not absolutely sure, but at the equator the sun’s energy at its highest, promoting photosynthesis, which pushes the plant and animal life to a top rate of production.
There are other factors in the distribution of birds. Age of population is one of them. In areas where the birds have been there for eons of time, the population has time to diversify and evolve into more species.
North America is an example. During the Pleistocene, an era where there was repeated glaciation, many birds became extinct, including some very large eagles and vultures.
South America and Antarctica have the largest number of bird species of any area in the world, with more than 3,100 of the world’s number of 9,930, nearly a third. The Amazon Rainforest has up to 300 species in a square kilometer. That is enough motivation for a birder to book his/her travel to South America today.
Africa draws the world to see its four-legged animals, including giraffes, hippos, lions and zebras. However, the continent also has 2,500 species of birds; a not so shabby number compared to South America’s 3,100.
The continental drift has isolated Australia and New Zealand, giving nature the opportunity to evolve and diversify. Coupled with the Pacific Islands, the countries have 1,700 species total.
If you are keeping a lifetime bird list, Europe can add 500 species and the Middle East 650 to your list. The bird numbers mentioned total more than the 10,000 for the world as some birds appear in two or three regions or continents.
The book “National Geographic Global Birding Traveling the World in Search of Birds” was my primary source for this article. I have attempted to show where in the world the birds are. I hope that you are able to get out and see them.
Norma Erickson is a longtime bird watcher who lives in Greeley