The Dauset Trails Newsletter January 2011
Wings of Destiny
Many mammals, birds, fish, reptiles, and insects take a seasonal, lengthy journey by water, land, or air. This journey, known as migration, is an instinct that creatures have that ensures their survival.
Monarch Butterflies, Purple Martins, and Sandhill Cranes migrate great distances. Here are some interesting facts about each:
The Monarch Butterfly (Danaus plexipus) migrates in stages that take several lifetimes to complete. The Monarch Butterfly migrates northward from Mexico. The journey is long and dangerous for this insect. Once the Monarch's migration begins, it will take three to four generations to push their way north and only one strong generation will make the flight back to the south.
The first three or four generations of Monarch Butterflies only live two to six weeks as adults.
The first generation develops during the spring in Mexico. They will fly northward as far as they can. They lay their eggs on a plant called milkweed.
The egg-laying adult Monarch then dies. The eggs become larvae and feed on the milkweed. Toxic chemicals in this plant transfer into the larva's skin which provide an unappetizing protection for the developing caterpillar. These chemicals make the caterpillar taste awful to predators. The caterpillar finishes developing and forms a chrysalis structure that encases and protects its body as it further develops into the adult butterfly.
The newly formed adults are the second generation Monarch. They continue the journey as far north as they can travel. They lay their eggs and soon will die. The eggs grow through the stages of larva, pupa, and adult. The third generation adult Monarch flies as far north as it can. There the process is repeated. The fourth generation Monarch will finish the journey to the north, then lay their eggs and soon die.
At the end of summer a stronger breed of Monarchs develop. These Monarchs will live six to nine months- a lot longer than the generations before them. When temperatures drop in the fall, the Monarchs will fly non-stop back to Mexico. The journey will take about two months to complete. Next spring, the rested adults lay their eggs and die. Migration will begin again.
for more information: visit http://www.monarchbutterfly.com/, http://monarch.pwnet.org/mom/kick_off.php, http://www.nhm.ac.uk/about-us/news/2007/june/news_11893.html, National Geographic Kids Great Migrations Butterflies, Copyright 2010,National Geographic Society, Washington DC, 20036
||Speaking of migration, Purple Martins and Eastern Bluebirds are coming through. Make sure your martin houses are hanging and your bluebird boxes are cleaned for the new arrivals.|
Purple Martins (Progne subis), native to North America, are the largest member of the swallow family. They winter in South America and return to this area in mid February.
Native Americans discovered that Purple Martins would nest in hollowed-out gourds. They also realized that flying insect numbers declined when more martins were attracted to their areas.
Martins eat flying insects including house flies, butterflies, moths, and dragonflies. A few mosquitoes are eaten but not many. Martins will also eat eggshells and crushed oyster pieces to help with egg production and to give young some grit to aid their digestion.
Martins prefer to live close to homes and barns as opposed to the middle of a field. Martins have learned that there are fewer predators near people's homes.
Gourds should be hung 12-15 feet off of the ground.
Sandhill Cranes (Grus canadensis) will pass through Georgia in February. They are flying back to the Great Lakes and Canada from their wintering stay in Florida. They fly in a "V" formation at high altitudes of 3-5,000 feet- even higher when flying over mountains. They have a loud trumpeting sound that preceeds their passing. They can fly 50 mph and cover up to 500 miles in one day.
Sandhill Cranes are long-legged birds standing three feet tall with a wingspan of six feet. They have gray feathers with white cheeks and a red forehead. Their dagger-like beak enable them to stab and grab insects, aquatic plants, tubers, cultivated grains, and berries. They prefer fresh water habitat.
|Sandhill Cranes are confused with Great Blue Herons. Great Blue Herons do not have red foreheads. They fly with their neck tucked in an "S" shape. The Sandhill Crane flies with its neck straight.|
|Migration is an instinctive adaptation for many wildlife species. The journey provides a means to find more food or a mate. Though the trip can be costly for some, the majority survive, and new generations will continue the migration experience.|
Dauset Trails Nature Center
360 Mt. Vernon Rd. Jackson, GA 30233 (770) 775-6798