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Lesson Two
Bills, Beaks and Food
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Lesson Overview
These lessons were designed to accompany parts three, four, and five of the PBS Life of Birds series. Although this lesson plan was primarily developed for grades 9-12, teachers of elementary or middle school students can easily select and/or adapt the following questions and activities for use in their classrooms. Some suggestions for the younger student are included at the end of the lessons.

In "The Insatiable Appetite," students learn about the intense feeding necessary to fuel bird flight. This forces birds to utilize a variety of strategies to meet those needs. This episode focuses on the nectar feeders, seed eaters, and insect eaters that seem to be on an endless quest for food. Bill structure is important in determining what different species of birds are able to eat, so natural selection has played an important role in the evolution of bird feeding habits.

In "Meat Eaters," students are introduced to birds of prey. Birds of prey have fascinating physical characteristics that enable them to track, capture, and kill their source of meat, the richest of all foods. Acute sense of hearing, sight, and/or smell may be the key to their survival. From small Peregrine falcons to giant condors, a diverse array of predatory birds demonstrate their hunting techniques in a variety of habitats.

Because most of the Earth is covered by water, birds venture into the lakes, rivers, and seas of the world in order to find and collect food. We meet these birds in "Fishing for a Living." Skimming, harpooning, probing, diving, and swimming are among the many methods birds employ in the capture of aquatic organisms. Dippers, Kingfishers, darters, skimmers… their names often provide a clue as to their hunting technique.

Objectives
By the end of the lesson, students will:

  1. Understand how natural selection has influenced the evolution of bird bills, wings, talons, and other anatomical features that contribute to successful feeding.
  2. Identify the behavioral and physical characteristics that enable birds to obtain the food necessary to fuel their flight.
Related National Science Standards
from McREL Standards Database at
http://www.mcrel.org/standards-benchmarks/
standardslib/science.html
  • Knows ways in which species interact and depend on one another in an ecosystem (e.g., producer/consumer, predator/prey, parasite/host, relationships that are mutually beneficial or competitive).
  • Knows that heritable characteristics, which can be biochemical and anatomical, largely determine what capabilities an organism will have, how it will behave, and how likely it is to survive and reproduce.
  • Knows that natural selection leads to organisms that are well suited for survival in particular environments, so that when environment changes, some inherited characteristics become more or less advantageous or neutral, and chance alone can result in characteristics having no survival or reproductive value.
  • Knows how natural selection and its evolutionary consequences provide a scientific explanation for the diversity and unity of past and present life forms on Earth.
Strategies and Procedures
Before watching the videos, ask the students to think about what they have seen birds eat. On the board, compile a list of the food items that students recall. After viewing, students could then add to the list. The short-answer questions could then be distributed for completion during viewing to challenge the students to pay close attention. Several discussion questions and one or more of the activities could be utilized after viewing to reinforce the major concepts presented in the program.

Short-answer Questions for Episode Three:
(Note: time cues are provided to help the teacher and student locate information while viewing. Teachers may fast forward and ask students to answer only particular questions, if time is limited.)

  1. Food for birds should be energy-packed and not too bulky. What food source seems to provide just that? (1.50)
  2. Identify at least three species of birds that feed on tree sap. (11.00)
  3. Can you name the five parts of plants that different kinds of birds may use as food?
  4. Insects are everywhere, so it's no wonder that birds have developed a variety of ways to snag them. For example, although there are no woodpeckers in the Galapagos Islands, a species of finch uses a unique tool to catch insects. What is it? (34.21)
  5. A bird in New Caledonia uses a stick to "irritate" a grub until its prey grabs the tool. What kind of bird uses that technique? (37.30)
Short Answer Questions for Episode Four:
  1. What bird has the ability to hear ten times better that a human, hearing so sensitive that it can detect a lemming beneath the snow? (5.50)
  2. What unique feature allows the Kestrel to spot vole urine from high in the sky? (11.00)
  3. In the rainforests of Trinidad, one species of bird has wide-open nostrils and a well developed sense of smell to find the rotting carcasses of dead animals. What is it? (13.00)
  4. What bird has long double-jointed legs that allow it to reach into holes and under rocks for prey? (34.40)
  5. What is the largest bird of prey? (49.35)
Short Answer Questions for Episode Five:
  1. What is the largest species of bird that can hover over water in search of prey? (7.23)
  2. Different species of egrets are found all over the world. What do they eat? (9.40 and 10.15)
  3. Different species of ducks are adapted to different types of life on water. For example, mallards are "specialist dabblers" that dip their bills into the water for food. What do they eat? (16.15)
  4. How does the Open-billed Stork eat mussels? (21.40)
  5. One thing all sea birds have in common is the need to return to land to lay their eggs. What is the main advantage for finding a remote island to do so? (36.00)
  6. What species has the largest wingspan of any bird (as wide as 7 feet)? (43.46)
Discussion Questions for Episode Three:
  1. Describe the unique dietary supplement required by the crossbills of California and the parrots and macaws of New Caledonia. Explain why these birds need this supplement. (5.20 and 52.00)
  2. Explain how some jays and woodpeckers prepare for winter when food is scarce. (7.21)
  3. Because many plants rely on birds to pollenate them, they have developed a variety of ways to attract them. Describe some of the features of plants that have established mutualistic relationships with birds and give examples. (20.50)
  4. Some birds have developed some interesting symbiotic relationships with other animals to help them obtain food. Discuss some of these relationships and explain how both the bird species and the other animals might benefit from the arrangement. (45.5)
Discussion Questions for Episode Four:
  1. African Flamingos are part of one of the shortest food chains in the world. Identify the members of this food chain. What biological terms best describe the ecological niche each animal fills? (26.30)
  2. Peregrine falcons are considered the most specialized hunters of all. Discuss the characteristics that earned them that reputation. (44.10)
  3. Beeches provide a habitat rich in sources of food for a variety of birds. Several kinds often assemble there, yet competition isn't a problem. A form of "resource partitioning" occurs in which Godwits, Dowitchers, Sanderlings, and Abicets seem to share the wealth. Describe the feeding habits of these birds and explain how they avoid competing for food. (28.09)
  4. Petrels and other birds that fly over the open ocean have a "tube nose" that is crucial to their survival. What is the function of these tubes and how do they help these birds survive? (38.40)
Activities for the Older Student (grades 9-12)
  • Download pictures from a Web site such as the Bird Images Gallery http://www.scn.org/earth/tweeters/images/ or Peterson's Online at http://www.petersononline.com/birds/month/index.html, or draw pictures of different types of bills. Describe or show how the structure of the bill is designed for eating a specific type of food. For example, a spoonbill has the ideal tool for gathering tadpoles, beetles, and aquatic insect larvae from bottom mud. You could even do a "Predator/Prey" Lab in which each student would be a "predator" provided with a specific "feeding appendage" (plastic spoon, fork, knife, or even forceps) and a plastic cup (or stomach) to collect the prey. The "prey" could include five or six different size beans or seeds, such as kidney beans, lima beans, split peas, barley, and even dried elbow macaroni. The "prey" would be mixed together in a container and then scattered on the floor (some school floors have a pattern in them that would provide a great "camouflaged" background). At the teacher's signal, students would begin a "feeding frenzy" that would last one minute. After feeding, students would stop to categorize and count the prey they had "consumed". They could record their data in a spreadsheet and look for feeding patterns. For example, which prey was most popular? Which predator was most successful? This procedure could be repeated for several "generations" in which surviving prey "reproduced" at a rate of two offspring for every pair of survivors. The number of each predator type could also be changed to reflect feeding success. Then students can graph the change in population size of prey species (or even predator species).
  • The Galapagos Islands are 700 miles from the nearest mainland, yet there are more than 150 different kinds of birds there. Select one family of birds from these islands and, using library or online resources, report on the unique anatomical features and/or behavioral characteristics that have helped them survive. You might select the Blue-footed Booby, Mockingbirds, Cormorants, Turns, Shear-waters, Petrels, or the infamous Finches. One resource that might be helpful is the Scientific American Frontiers web site for Destination: Galapagos Islands at http://www.pbs.org/cgi-bin/saf/gi.pl .
Activities for the Younger Student
  • Set up different kinds of bird feeders, each containing a different type of food. You might try sunflower seeds, a mix of small seeds, a suet cake, peanuts, or a sugar solution. The feeders should be placed strategically so squirrels can't get to the food. Then you can observe each feeder and note the kinds of birds that eat each type of food. What characteristics do the birds visiting each feeder have in common? Do they have any special adaptations that allow them to eat a particular type of seed? Students could keep a data sheet (or spreadsheet) of their observations and write conclusions after analyzing that data. The feeders might also provide some great photo opportunities.
Related Web Sites: About the Lesson Plan Author
Laurent Gaudreault has taught biology for thirty years in Fairfax County, Virginia, and has been teaching at The Jefferson High School for Science and Technology since its inception in 1985. He has provided lesson plans for some of The National Audobon Society Specials and presented workshops at the National Association of Biology Teachers Annual Conventions in 1995 and 1996.
 
Lesson Overview

Objectives

Related National Science Standards

Strategies and Procedures

Lesson Overview

Related Web Sites

About the Lesson Plan Author
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