We thought we would begin this article with a few of questions….What bird has breeding grounds in the Arctic and flies to its non-breeding grounds in Antarctica and then returns to the Arctic to nest again year after year? How high is the highest altitude a bird can fly? Do birds use the stars to navigate? Do birds use compasses to help them find true north? (Answer in the “Did You Know” Section)
In the last article we talked about phenology, the cycle of events that occur year after year — annual events. We shall focus on one of these events, bird migration. One of the best descriptors of migration has been given by Keith Bildstein, a noted ornithologist, Migration – the seasonal, directed movements organisms undertake while traveling back and forth between their “breeding grounds” and their “wintering area” – occurs in almost all forms of life, plant and animal, large and small, and most of what is in between.”
Migration patterns in birds have evolved over millennia, responding to seasonal shifts in the amount of light, temperature and especially food available to them. Most get the urge to migrate as conditions deteriorate within their environment. Some birds only migrate 20 miles while others migrate 20,000. To prepare for migration, birds become hyperphagic. This process is similar to animals as they prepare for hibernation. The increase in food consumption is stored as fat for the long journey ahead. Some birds do not migrate and remain year round. We are familiar with several of these species: pileated woodpeckers, downey woodpeckers, red-bellied woodpeckers, tufted titmouse, white breasted nuthatch, several species of owls, and cardinals.
There are three important concepts in understanding the migratory patterns of most birds; breeding range, year-round range, and winter range. These concepts are self explanatory and there can be some overlap of the ranges depending on the species.
There are three types of migration patterns: Complete, Partial, and Irruptive. We are most familiar with birds whose migration pattern is complete. This pattern occurs when all birds of a species leave a range; (e.g.)shorebirds, tanagers, warblers, orioles, hummingbirds and most hawks of North America. The wintering range for most complete migrants from North America is South and Central America, the Caribbean basin, and the southernmost United States. Most birds move in a north – south direction; however there are a few who move from an east – west direction, moving between Manitoba and Saskatchewan and the Eastern seaboard. By far the most common type of migration is partial where most birds of a species leave a particular range. Partial migration is characterized by seasonal movements from the breeding ranges to their year- round ranges, and their ranges commonly overlap. Familiar examples are the red-tail hawks, goldfinches, several warblers and sparrows, eastern blue birds, wrens, and of course the robin. Irruptive migrations are not seasonal or predictive.
This type of migration usually occurs when sudden declines in food source occurs or with a temporary change in the environment and most of the species leave their range. Remember the appearance of Snowy owls here this year due to the decline in the lemming population farther north.
Birds don’t have AAA, MapQuest, or Google Maps but they do have “flyways”. North America is divided into four different flyways that look like big funnels directing the birds south. They’re called the Atlantic, the Mississippi, the Central and the Pacific Flyways. Except along the coasts, the flyway boundaries are not always sharply defined, both in the northern breeding and the southern wintering ranges. As a matter of fact, in the region of Panama, parts of all four flyways merge into one. Northeast Ohio sits in the Atlantic Flyway. This flyway encompasses the offshore waters of the Atlantic Coast west to the Allegheny Mountains where, curving northwestward across northern West Virginia, it continues in that direction across the prairie provinces of Canada and the Northwest Territories to the Arctic Coast of Alaska. The flyway encompasses several primary migration routes and many more that are important as tributaries, some of the latter being branches from primary routes of other flyways. The Atlantic Flyway route from the northwest is the main route for many passerines, hawks, ducks, geese, and swans. Cape May in New Jersey is located at the bottom end of the funnel and is a Mecca for many bird enthusiasts.
Most passerine or perching birds are described as powered migrants, with constant wing beats, as opposed to the soaring migrants such as the hawks, storks, cranes, and swallows. This is an important distinction, as it dictates when they fly. Soaring birds fly during the day while the powered birds fly mainly at night. The soaring birds use what are called thermals, the warm air that rises from the ground that allows them to soar at very high altitudes for great distances. Several species often use the same thermals during their migration. At Hawk Mountain last year, 23,000 hawks passed through riding the thermals. The powered birds fly at night for several reasons. The air is much cooler at night allowing for their bodies to keep cool, there is less air turbulence, requiring less energy usage, the use of stars for navigation, less predation by hawks and other birds, and the need to refuel during the day when food sources can be easily identified.
Most birds won’t set any speed records while migrating. The smallest birds fly the slowest, anywhere between 10-30 mph, while waterfowl fly the fastest, 28-50 mph. As the soaring birds use the thermals to gain altitude they fly very slowly around 10-15 mph. However, as the move from thermal to thermal they can reach gliding speeds of up to 45 mph. The use of prevailing winds is very important to all migrants.
Throughout the migratory trip, birds must stop along the way to rest and refuel. They face the daunting challenge of flying over vast stretches of water, desert, and mountain ranges without stopping. They must deal with unfavorable weather patterns and man-made obstacles, not to mention the destruction of habitat. This is truly one of nature’s remarkable stories.
There are several web sites that can give you an idea of which birds will be passing through our area during the spring and fall migration. http://www.bsbo.org/birding/migration.htm is an excellent site full of up-to-date information. It lists species and expected arrival dates. Another site is http://birdingonthe.net/mailinglists/OHIO.html#1331154563 which is a state-wide list of bird sightings.
Don’t forget to get a good field guide so you can accurately identify the birds you are seeing. There are several to choose from: Sibley Guide to Birds, Peterson Guide to Birds East of the Rockies, National Geographic Birds of North America and the various Kaufman field guides. For Smartphone users, iBird and the National Audubon are excellent apps. Now go out and enjoy ….Nearby Nature!
Did You Know?
The Arctic Tern fly’s from its breeding ground in the Arctic to it’s wintering grounds in the Antarctic, 18,000 miles.
The Bar-headed geese have been recorded at an altitude of 29,000 feet (5 miles) as they fly over the Himalayan mountain range.
Most night flying birds use celestial navigation. Researchers believe that in the first year of life, birds memorize the position of constellations in relation to the North Star. The moon may play a role assisting birds along the way.
Birds do indeed have an internal ability to determine the earth’s magnetic field. This allows them to find true north. Researchers believe birds have a mineral called magnetite above their nostrils. This mineral helps them navigate using the earth’s magnetic fields.
More Nearby Nature
Audubon Bird Walks – April 15, 22, 29; May 6, 13, 20 (7:30-9:00am) Experienced and beginning birders are invited for these walks as we set out early Sunday mornings to learn and record the sights and sounds indicating the return of our feathered friends from distant lands. Bring your binoculars and meet at the JH Barrow Field Station on Wheeler Rd. (between SR 305 and SR 82) near Garrettsville. It is a great way to learn birding from experts. No registration is necessary. For questions, call 330.569.6003.
Knee Deep in Bluebells – Sunday, April 22 (3:00-5:00pm) One of the most unbelievable and spectacular sights in all of Ohio is the riot of wildflowers at the 250 acre Poland Municipal Forest southeast of Youngstown. Here, in a setting among some of the largest trees in the state, thousands upon thousands of wild bluebells and other spring wildflowers bloom. The forest floor is literally awash with a carpet of bluebells, dabs of red and white trilliums and a haze of marsh marigolds; the artistry of nature in all it is glory. Sponsored by the Friends of the Hiram College Field Station (hiking fee: $3 for members, $6 for non-members). To register, call 330.569.6003 or email email@example.com. Directions provided upon registration.
Send your questions or comments to: firstname.lastname@example.org
Matt Sorrick is Director of The Center for Science Education at Hiram College.
Joe Malmisur is an executive member of the Northeast Ohio Forestry Association and amateur naturalist.