Clues from the Sunflower Feeder

Two Visitors to the Feeder

Nora and Malik watched a sunflower patch beside a backyard bird feeder for three weeks. They compared the sunflower plants with house finches that visited the feeder. They sketched parts they could see and read about parts inside each living thing. They did not remove any living plant or animal. Instead, they made careful observations and used safe models.

The sunflowers had broad leaves on green stems. Their roots held the plants in the soil. When a plant's stem was bent sharply, the leaves above the bend drooped by the next afternoon, even though the soil was damp. A plant with an unbent stem stayed upright. The class learned that tiny tubes inside the stem move water from the roots toward the leaves. The leaves used light to make food for the plant. Later, the flower heads became filled with seeds. The seeds could begin new sunflower plants when conditions were right.

House finches used their short, thick beaks to pick up and crack sunflower seeds. Their claws held the feeder perch while they ate. When a finch flew from the feeder to a nearby branch, its wings and feathers helped it move through the air. Inside its body, lungs took in oxygen, muscles pulled on bones, and digestive organs broke food into smaller materials the body could use. The class also saw a finch carry nesting material to a shrub. A week later, an adult finch brought food to chicks in the nest.

To study the beak observation without handling a bird, the students made two clay models. One model had a short, thick tip. The other had a long, narrow tip. Each model was used for one minute to pick up the same kind of sunflower seed from the same tray. The students kept the tray, seed amount, test time, and starting position the same. The short, thick model picked up 18 seeds. The long, narrow model picked up 9 seeds. The models did not show what happens inside a real finch.