Monday, October 31, 2011

Adironack Wildlife: The Fall Loon Migration

It is typically in November when ice forms on the many ponds and lakes across the Adirondacks. This inevitable transition from a watery world into an icy plain causes the loon to abandon its summer home in remote wilderness locations and seek out an environment in which it can survive until the spring.

This process of relocation begins with the loons leaving their more traditional breeding grounds in remote ponds and back country lakes and moving to larger lakes in the same general region. Because large bodies of water take longer to freeze than smaller aquatic settings, traveling to much larger lakes gives the loon more time in its northern, fresh water environment before heading south.

Birds that were unsuccessful at nesting, or individuals that lost their chicks to predators during the summer, are usually the first to arrive at these more sizeable bodies of water just as the leaves start to turn color. The next group of individuals to join the developing flock is the adult birds that recently left their now independent chicks. Finally, the birds that hatched roughly four months ago make it to these large lakes as their wings are now strong enough to carry them to new surroundings. This is usually after many of the leaves have been shed from their twigs.

During the summer breeding season, it is a rare occurrence to see more than two adults swimming in close proximity. From the time loons arrive in mid spring until their chicks are becoming proficient at catching fish, adult birds are quite territorial. However, as their young gain independence, the adult’s urge to drive off intruding neighbors quickly fades. On some highly preferred lakes, that act as staging areas prior to migration, it is not uncommon to see several dozen or more loons actively feeding near one another.

It has been suggested by some naturalists that the loon gathers in such loosely knit flocks in order to improve its chances of catching fish. As the water’s temperature cools significantly in autumn, some of the fish on which this aquatic bird preys change their routine and gather into more sizeable schools. As these fish attempt to avoid one diving loon, other loons quickly approach from a different angle and can be more successful at snagging a meal than if they acted alone.

Like most migratory birds, the loon waits until the wind is blowing in a favorable direction before it abandons its North Country residence. Within a day after a cold front passes the region, many of the loons take off and slowly climb to an altitude of 5000 to 8000 feet. (This is in contrast to many other birds which migrate at night and fly within a hundred feet of the tree tops, which is why power lines, cell towers and wind mills are often fatal obstacles to migratory birds.) By reaching altitudes of 6000 feet or more, the loon can take advantage of the much stronger winds that occur at these altitudes.

It is quite common to have these upper air winds in excess of 40 mph in the days following the passage of a cold front. Since a loon is capable of flying at a speed of 25 mph in calm air, this massive bird is able to move across the terrain below at speeds of 60 mph or more with the help of these northwesterly breezes. Some researchers have recorded loons making their flight from the Adirondack region to the Atlantic coastline in as little as four hours.

Once these birds reach the open water off the coast of New England, Long Island, or the Jersey shore, they may remain together or drift apart and eventually join other groups of loons that have formed in the area. Loons from the Adirondacks may remain in relatively northern to mid-latitude ocean waters for the entire winter; yet some are known to travel much further down the coastline. But before the loon engages in any further bouts of long distance travel, it spends time feeding in an attempt to rebuild fat reserves used during the initial segment of its migration.

Over the course of the next few weeks, loons will be flying toward the seacoast. However, the chances of noting a collection of these unique birds is slim, as they fly too high and too fast, and without the noise that accompanies geese as they work their way to more favorable winter surroundings.

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Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.

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