Turkey time: celebrate thanksgiving with these wild birds.
Amazingly, the plump turkey you now eat for dinner was once as thin as its wild cousins. Hundreds of years ago, the Aztecs (ancient culture that thrived in Mexico) domesticated wild turkeys for food. When Spanish explorers saw the birds around 1500 A.D., they took them back to Europe and bred them for the poultry industry. "They were bred to produce meat," says Dickson. "So they have giant pectoral [chest] muscles. They get so heavy they can hardly walk." Turkey became a mealtime hit that quickly spread throughout Europe. In the 1600s, the first colonial settlers brought the domesticated turkey back to North America. "Basically, the turkey made a round trip [between the U.S. and Europe]," says Dickson. And it returned as a very different looking bird.
As the number of domesticated turkeys multiplied to suit the American diet, their wild relatives suffered a different fate. "[Wild turkey] populations were once superabundant," says Dickson. But the settlers began chopping down their forest habitats, leaving the birds little room to live or find food. By the early 1900s, fewer than 100,000 wild turkeys remained in the United States.
Since the 1950s, conservation efforts--including stricter hunting rules and measures like trapping the birds and then releasing them into healthy forests--helped restore wild turkey populations. "Today, there are about 6 million wild turkeys in the U.S.," says Dickson. That's something to gobble about.
Follow the steps above to learn about wild turkey babies.
1 Baby Sitting
Spring is wild turkey breeding season. During nesting time, a hen (adult female turkey)-which usually roosts (sleeps) in trees at night--stays on the ground. She finds a spot among the bushes. There, she spends about two weeks laying a clutch (nest of eggs) of approximately 11 eggs. Like most ground-nesting birds, a turkey hen does not start incubating (sitting on the eggs, warming them to hatch) her eggs fulltime until she has finished laying her entire clutch. "During incubation [which takes 28 days] and hatching, the scent and activities surrounding the nest are very attractive to predators [like foxes]," says Dickson. The hen needs all of the pours (baby turkeys) to hatch around the same time. This way, she can round up the flock more easily to flee the predator-luring nest.
2 Home Schooling
Turkeys are precocial (prih-CO-shul); the newborns develop physically and socially early. "They are not like those helpless altricial (all-TRIH-shul) birds [songbirds, for example] that require feeding in the nest," says Dickson. "[Turkeys] can't stay in the nest, or the poults would get eaten by predators." Survival training begins even before eggs hatch. The hen calls to her embryos (developing young), encouraging them to crack their way out of the eggshell. The hatched poult then goes through imprinting, or the process of identifying with and establishing an attachment to social figures--like its mom and siblings. This process takes up to 48 hours. Once the flock identifies with each other, it takes off for safer grounds. Being a quick learner has its pitfalls: If the hen is not present during imprinting, the poult will identify with whatever it sees--including barnyard animals, for example. "Once it thinks it's a goat, it's stuck," says Dickson.
3 Flight Training
Poults can't fly at first, so the hen raises them on the ground. At night, they roost underneath the warmth of her wings. At about two weeks old, poults begin flying to tree branches to sleep, where they are safer from predators. They start on lower branches and then aim higher. Still, turkeys can only fly so far. They are Galliformes (GA-la-forms), a classification of birds adapted for short, rapid flight. A turkey has a high wing load, or weight-to-wing ratio. Hens weigh about 5 kilograms (11 pounds), and gobblers (adult male turkeys) may be double that in heft. Short wings can't carry the heavy bird far. "It has been said: If you [were to] pursue a wild turkey, you [would] catch up to it after three flights," says Dickson. "It gets exhausted."
DID YOU KNOW?
* Turkeys can swim. Like ducks, they use their feet for propulsion. "But unlike ducks, they do not have webbed feet," says wildlife scientist James Dickson of Louisiana Tech University. Without this flipperlike feature, swimming is more strenuous.
* The breast meat of the bird you eat gives a telltale clue about its flight behavior. Birds with dark breast meat, like ducks, can fly for longer distances than birds with lighter breast meat, like turkeys. "The dark meat indicates they have ample blood supply to the pectoral muscle [which is vital for flight]," says Dickson.
* How does habitat loss contribute to the decline of animal species? Discuss and create a web of events on the blackboard.
HEALTH/MATH: Research to find the average number of calories and grams of fat in a typical Thanksgiving meal. Then create a bar graph showing the fat and caloric content for each item in the meal (turkey, gravy, cranberry sauce, etc.). Follow with a discussion on healthy serving sizes.
* Grolier search term: wild turkey
* Learn more about the increase in wild turkey populations at: http://biology.usgs.gov/s+t/noframe/b028.htm
CHECK FOR UNDERSTANDING
DIRECTIONS: Fill in the blanks to complete the following sentences.
1. Adult female turkeys are called --, and baby turkeys are called
2. Turkeys are --, meaning the newborns develop physically and socially early. They are the opposite of -- birds, like songbirds, which tend to be -- and require feeding in the nest.
3. During its first 48 hours of life, a baby turkey goes through --, or the process of identifying and establishing attachments to
4. Turkeys are not strong fliers. That's because they have a high --, meaning a high to -- ratio.
1. hens, poults
2. precocial, altricial, helpless
3. imprinting, social figures
4. wing load, weight, wing
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|Title Annotation:||Animal Behavior|
|Date:||Nov 22, 2004|
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