Lesson 1 - Radical Raptors, The Raptor Center at the University of Minnesota

By Carolyn Lane and Mike Kennedy
©The Raptor Center

State Goals for Environmental Education (as per the Minnesota State Plan for Environmental Education, Greenprint, 1993)

Students will:

  1. Understand ecological systems.
  2. Provide experiences to assist citizens to increase their sensitivity and stewardship for the environment.
  3. Understand that ecological interrelationships cross political boundaries and effects can be global.
  4. Understand the cause and effect relationship between human attitudes and behavior and the environment.
Learning Objectives

Students will:

  1. Define "raptor."
  2. Explain why raptors are important.
  3. Describe the unique physical characteristics of raptors.
  4. List various types of raptors.
  5. Explain the life cycle of raptors.
  6. Describe the food and hunting habits of raptors.
  7. Describe natural habitats of various raptors.
  8. Appreciate the importance of raptor preservation and restoration.
  9. Explain manmade threats to raptor populations.
Vocabulary Words Materials Background

"He clasps the crag with crooked hands; Close to the sun in lonely lands, Ring'd with the azure world he stands. The wrinkled sea beneath him crawls; He watches from his mountain walls And like a thunderbolt he falls."

Alfred, Lord Tennyson, "The Eagle"

Raptors are birds of prey belonging to the scientific orders Strigiformes and Falconiformes. This order is divided into six groups with a total of 446 species worldwide:

  1. Vultures (7 species)
  2. The Secretary Bird (1 specie in Africa)
  3. Hawks and Eagles (226 species)
  4. The Osprey (1 specie)
  5. Falcons (63 species)
  6. Owls (148 species)

For the purpose of this lesson plan, we will consider raptors as birds which share common physical traits, as well as some behavioral and natural history features. Historically, the new world vultures have been considered part of the falconiformes, but recent evidence has led some scientists to classify them as storks. Tradition, as well as shared natural history, will keep them in the raptor group for some time to come.

At one time, raptors soared the skies of America freely, the unquestioned rulers of the air. However, as more and more people settled throughout America, raptors often became the victims of hatred and were looked upon as "murderers and thieves." They were accused of stealing livestock from chickens to calves, and a vicious slaughter began. In fact, raptors seldom prey upon domestic livestock, but it wasn't until many eagles and other raptors were hunted to the point of near extinction, that any action was taken to halt the senseless killing.

Since then, we have come to understand more and more about the important role that raptors play in our ecology, thanks to places like The Raptor Center. Raptors are extremely important in controlling rodent populations and maintaining a healthy ecosystem with all levels of the system represented.

A list of Minnesota raptors follows:
  1. Eagles
  2. Hawks
  3. Falcons
  4. Vultures
  5. Owls

See a one-page illustrated Guide to Identification of Midwest Raptors

Some adaptations that raptors posses that enable their unique way of life include strong feet with long, sharp talons, keen eyesight, and a diet of primarily meat. A simple analogy to use in explaining adaptation to students is that of teeth. We have two types of teeth, which are adaptations that help us live. They are incisors (biters!) and molars (chewers!).

Raptors possess some very special adaptations or "tools of the trade" that make them excel as hunters of the sky. The first of these "tools of the trade" is their keen eyesight. It has been estimated that the eyesight of raptors is approximately eight times better than that of humans. This incredible vision is made possible by a very high resolving power. The eyes of raptors are so large that they have no room to move within the sockets or skull and can only face forward. Since raptors can't roll their eyes from side to side as we can, they have long, flexible necks which enable them to turn their head and nearly face backwards. This is why raptors turn their heads so frequently and so quickly. Owls have an added advantage over other raptors with their remarkably sharp night vision. Their eyes are even larger than those of other raptors, and the pupils can open very wide to let in a tremendous amount of light. The pupils can also close to a pinpoint, giving owls excellent vision during the daytime as well. Studies have shown that owls can see in dim light at least thirty-five times, and perhaps even one hundred times better than human eyes. Even on the darkest nights, they can still see every leaf and twig.

Raptors also have a keen sense of hearing. They make a broad range of noises and use their hearing as a means of communication. They also rely on it heavily for locating their prey, combined with their sharp vision. Owls use their ears to locate prey that they can't see and are especially adapted for night hunting with their three-dimensional hearing. Their ears are located in different positions on each side of the head, which allows them to judge the distance and direction from which a sound comes. The sound waves are also captured by the owl's facial disks. These features, combined with the ability to rotate the head in almost a full circle (280 degrees!), enable the owl to locate a sound coming from any direction. Even on a moonless night, most owls can locate their prey by sound alone. But if the prey stops moving and is silent, the owl then utilizes its sharp eyesight.

The talons of raptors are lethal weapons, perfectly designed for catching, holding, and carrying prey. Most birds of prey have three toes pointing forward and one pointing backward. These toes can exert an extremely powerful grip upon their catch and can literally crush it to death. The talons can also be driven into a vulnerable spot, such as the back of the neck, to quickly kill the prey. Eagles, and larger hawks can also kill their prey by dislocating the neck. The osprey have two toes facing forward and two facing backward. This allows them to hold the fish with four claws on each side. They also have spiny scales on their toes which help them hold onto the slippery fish. Owls also have two toes facing forward and two facing backward.

Once a raptor has captured its prey, it uses its hooked beak to tear the flesh into pieces. Eagles have particularly strong, tearing beaks. They force the hook of the bill into the meat, then using their feet to hold the animal firmly in place, they pull back, ripping off a piece of flesh. Certain owls have small beaks and others have large curved ones designed for ripping. Owls also use their beaks to signal aggression by clacking them loudly. Falcons use their beaks to help kill their prey. Their bill is specially adapted for severing the bones at the back of the victim's neck, killing it instantly.

Each wing shape determines the type of flight that results and even the type of prey that is pursued. This flight may vary from hours of soaring to wild sprints and dives. For example, a vulture may fly 200 miles in one day, searching for a dead animal to feed upon. Its long, broad wings enable it to soar and glide for large distances without flapping its wings, therefore conserving a great deal of energy. These huge wings are not very maneuverable, but since the vulture doesn't need to capture its own food, it is not a major handicap.

Large eagles must be able to both soar and catch their food, so they have somewhat shorter and narrower wings than vultures do. They also have much longer and stronger tails, which assist them in landing and turning quickly. Raptors which hunt birds and small animals in wooded areas must be able to fly rapidly and turn sharply among the trees. Therefore, they have short, broad wings and long tails that enable this type of maneuverability. Most falcons have long, narrow-tipped wings which allow them to fly very quickly and dive after their prey, usually smaller birds. This is called "stooping." The falcon uses its diving speed to knock the prey out of the sky with its talons. The Peregrine Falcon, in particular, is a spectacular diver, and is considered to be the fastest living creature, sometimes diving at speeds of over 180 miles per hour!

Since owls don't search for food from great heights, and they hunt in the dark when speed and maneuverability aren't so crucial, they usually have rather short wings and tails in comparison to other raptors. But they do have a very important advantage--silent flight. This is because of their soft feathers which allow air to pass through, producing very quiet flight.

When the partnership between predators and prey is operating efficiently, a balance is maintained in their populations. Predators depend upon prey for their food supply. In turn, the population of the prey is strengthened, as the sick and weak are taken out. This leaves the strongest ones to reproduce. Without predators, the numbers of the prey species would quickly overpopulate, causing overcrowding, disease, and starvation. Raptors are especially valuable to people as an important source of rodent control. Their diet of primarily rodents prevents huge losses of agricultural products.

When something disrupts the food chain at the bottom, it is magnified at each succeeding level. When it reaches the top, the disturbance appears as a major environmental disruption. This makes raptors and other predators especially vulnerable the when food chain becomes unbalanced. This is why raptors serve as environmental barometers.

For example, raptors have been prime indicators of the environmental damage caused by the use of pesticides, such as DDT. When chemicals are sprayed on weeds, crops, and trees, they are also absorbed by small plant-eating animals, such as mice. These animals are then eaten by raptors. When the raptors eat enough of the contaminated animals, the pesticides build up in their bodies, often causing them to die from pesticide poisoning. If they survive, they often become sterile, or their egg shells are so weak that they break. Without being able to reproduce successfully, many raptor populations have decreased dramatically. When this happens, humans should realize that something is terribly wrong with our environment.

As a result of raptor population declines, these birds are now protected by law with the Federal Migratory Bird Protection Act and the Endangered Species Act. Violation of these laws carries heavy fines, and sometimes even imprisonment.

Activities
  1. Ask students to relate to you what they already know about raptors. Encourage them to think of both positive and negative experiences with raptors. (Do not differentiate between correct and incorrect information. Your goal is to guide them in examining their opinions about raptors. After the program, those with incorrect information will discover on their own that their perceptions were incorrect. It is important to not embarrass students.)
  2. Show the students the raptors which are common to Minnesota. Give them information about the general families of raptors to which they belong: eagles, vultures, accipiters, harriers, buteos, falcons,and owls. Then give them a short summary of the identifying characteristics, range in Minnesota, habitat, nesting, feeding habits, and conservation status.
  3. Play the "Habitat Game". (Older students may skip this game and instead discuss different Minnesota habitats and their features. A creative writing exercise may encourage them to thinking about the components of a habitat.) To play this game, choose five players--ideally volunteers--to "create" a habitat common in Minnesota. Each player chooses to play one of the environment's components, such as a plant, animal or physical feature. Secretly tell the selected group of five players what Minnesota environment they will "act out" or "create". For example, if the Boreal Forest was picked one player could act out a Balsam Fir tree, another a Paper Birch tree, another a Pileated Woodpecker, another a Least Chipmunk, and a fifth student could act out a Goshawk. While each group performs, the people in the larger group watch, refraining from guessing the environment until the performers have finished their act. After the players have performed for several minutes, ask the audience which environment is being portrayed. Before the players leave the "stage", have each student introduce the character he/she is playing, in order of appearance. Encourage applause. Minnesota environments that are easy to portray are: boreal forest, tall grass prairie, mixed-hardwood forest, pine forest, lakes, rivers, etc... (Adapted from the book; Sharing the Joy of Nature, Nature Activities for All Ages, Joseph Cornell, Dawn Publications, 1989, ISBN 0916124525)
  4. The Web of Life Game can be played in addition to the game above or in its place. This is a group game which demonstrates the interdependency of plant and animal species in an exciting and visual way. The game can be modified to suit the needs and ages of your students. You will need: large ball of yarn, 5 X 7 index cards, marking pens, scissors, hole punch. Each student selects a bird or animal to portray in the game. To ensure that a variety of species are represented, have students select animals from a list that you have prepared beforehand. Include various raptors and other predators, as well as animals, insects, etc. which function as prey. Students should research their animal to find out what it eats and how it lives. These facts can be written on the back of the card. Several students should also represent plant food sources. At game time, students put on their animal names and stand in a circle. Tie a loop in the loose end of the yarn and slip the loop over your wrist. Holding the ball of yarn, explain to the students that, together, you will be creating a "web of life." Start the web by saying, for example," I'm an eagle and I need rabbits to eat." The yarn ball is passed to the student wearing the "rabbit" card. The "rabbit" can say "I'm a rabbit and I need plants to eat," then pass the ball to the "plant." The "plant" may then say, "I am also eaten by deer," and so forth. The game continues until all the students are connected in a tangle of string. Before anyone lets go, recap what has happened. Talk with the students about the dependency of each creature on other creatures for survival. Have students predict what would happen if the string was cut. Cut the string dramatically and then let them draw conclusions about what happens. Discuss what happens to the "Web of Life" when food sources are depleted. Why are predators at the top of the food chain particularly vulnerable?
  5. Every bird possesses several types of feathers. These different types of feathers are all adaptations which help the bird survive. The feathers which cover the body and give it shape are called contour feathers. Those which extend out and give the bird the ability to fly are called flight feathers. Down feathers are small and fluffy, and act as insulators by trapping air next to the bird's body. Examine a contour or flight feather with a magnifying glass. Notice the hollow tube, or shaft, that runs the length of the feather. The rest of the feather is called the vane, and is made of hundreds of small barbs that branch off of the shaft. Thousands of tiny barbules grow off of each of the barbs. Now, draw a picture of a feather and label the shaft, vane, barb, and barbules. Pull a piece of Velcro apart and examine it with a magnifying glass. Notice the tiny loops and hooks. These are very similar to the way in which the barbules of a bird's feather interlock. This interlocking system is crucial to the bird's ability to keep its smooth shape while flying. Now rub your finger down the edge of the feather to "unlock" the barbules. Then rub them in the opposite direction to "lock" them again. The bird accomplishes this by "preening" its feathers with its bill. Owl feathers don't have as many barbules, so their feathers are somewhat fringed on the edges, allowing air to pass through. This is why they can fly so silently. Preening also helps to clean and waterproof a bird's feathers. A special oil-producing gland is found at the base of the rump. The bird squeezes out this oil, then spreads it on its feathers with its beak. This keeps the feathers waterproof. To see how this works, spread Vaseline on one contour feather. Then dip this feather and a second feather in water. What happens to the feather with Vaseline? What happens to the feather without Vaseline? Why is this important to the bird?
Discussion
  1. Create a description of the habitat you live in and list all the producers, consumers, and scavengers which live in your habitat.
  2. Discuss the different adaptations we have as humans and why they help us survive.
  3. Ask students to name the five senses. Ask them to (verbally) list those English words which are based on sense. Discuss the importance of senses.
  4. Ask students to define observation. How important are the senses to observational skill development? Do we use all our senses all the time? Part of the time? Do we miss things if we don't?
Extensions
  1. Create posters for school hallways to heighten awareness of raptor preservation. Hold a poster contest.
  2. Use the Internet to communicate with another class that is studying raptors. Compare your activities, ideas, discoveries, and future plans.
  3. Write a story about a young raptor and its struggles to find an unoccupied territory, learn to hunt in an environment filled with people, and its dilemma when a shopping mall is built in the middle of its hunting and nesting territory.
  4. Choose a specific raptor and conduct an in-depth study of its characteristics, habits, population declines/increases over the years, and the ways in which humans have affected its survival.
  5. If there is a raptor rehabilitation center in your area, inquire if they have a raptor adoption program. For information on The Raptor Center's adoption program, write for a free brochure at: The Raptor Center, 1920 Fitch Avenue, St. Paul, MN 55108, or call (612) 624-4745.
  6. To learn more about the winter habitats of raptors, establish a partnership with a group in Latin America, or adopt a reserve or park in Latin America. For more information, contact the National Wildlife Federation, International Programs, 1412 16th Street, N.W., Washington, D.C. 20036; (202) 637-3776.
  7. Write a cinquain poem:

    First line: Name of object (noun)
    Second line: Two words to describe the object (adjectives-each word should be a separate thought)
    Third line: Three words which tell what the object does or can do (verbs-each word should be a separate thought)
    Forth line: Four words to describe how you, the poet, feels about the object (adjectives and adverbs-again, each word should be a separate thought)
    Fifth line: Repeat the first line or use a synonym

    EXAMPLE:
    eagle
    graceful, fierce
    kills, eats, soars
    magical, powerful, warm, mighty
    the national bird
Resources

These, and other resources are available from The Raptor Center. For more information, please refer to the Gift Shop Catalog in the Main Menu or call The Raptor Center at (612) 624-4745.

BOOKS:

(**These books are excellent for 5th and 6th grade students.)

VIDEOS: CD ROM'S:
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The University of Minnesota is an equal opportunity educator and employer.

Last modified on Friday Jun 25, 2004

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