Bird Populations

What You Need

Bird Populations


To understand how scientists discern patterns and changes in bird populations.


In this lesson, students will study bird migratory patterns and the methods that researchers use to study them. Students will be introduced to the concepts of the study of bird movements.

The pursuit of scientific explanations often begins with a question about a natural phenomenon. Science is a way of developing answers, or improving explanations, for observations or events in the natural world. In this lesson, students will learn about how scientists study population movement in birds. By high school, students may begin to relate scientific inquiry to laboratory experiments in which conditions can be controlled and variables isolated. Students need to learn that in reality scientific inquiry can take many forms, but even in field work there are accepted methods and standards that are used to develop scientific knowledge.

Research indicates that students may commonly believe that science is concerned with invention or solving of practical problems and do not appreciate that the fundamental basis of science is a way to explore and understand the natural world. It is important for students to understand that different kinds of questions require different kinds of scientific investigations. Nonetheless, all scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories.

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Begin by asking students to tell you what they know about how scientists do their work. How would they describe a scientific investigation? Get students thinking about the process of scientific inquiry and the nature of science. This also is an opportunity for you to assess their current understanding of science. Accept student answers and record key ideas on a transparency using an overhead projector or chalkboard.

Continue the discussion by asking students to describe how scientists gather evidence. Students may give examples that are similar to the experiments they have conducted in class. They may talk about variables and controls. If students do not themselves make the connection to situations in which the conditions cannot be controlled, ask questions that will lead them to think about these cases. For example, "How do you think scientists obtain evidence about increases or reductions in animal populations? How might the methods used differ from those used to test for the presence of toxins in water samples?"

Then introduce the topic of the movement of bird populations. Talk about and list students’ definitions or pre-understandings of how bird population movement might be characterized. It is not important that students understand this very much but it is likely that students will mention things like seasonal migration. Make sure that students understand that by population movement we don't just mean flying around from tree to tree within a habitat to find food. Tell students that they will learn about how scientists study bird populations and the methods that they use to gather evidence and make explanations.


Begin this part of the lesson by discussing questions such as:

  • How do we track changes in human population? (We collect census information.)
  • What do we do in a census? (We count people and record certain characteristics.)
  • So what do you think might be a way that scientists can track bird populations? (They could count them.)
  • How do you think they would count birds? (Answers will vary.)

Part One: Gathering Data About Bird Populations
Using the A Closer Look at Bird Populations student esheet, students will explore these resources:

After students have completed Part 1, discuss their answers to the questions posed on the student esheet.

Part Two: Monitoring the Movement of Bird Populations
In the rest of the lesson, students will explore the different movements of bird populations in greater detail. They will begin by reading the Overview and the Discussion sections on the Movements of Bird Populations website. Students should use the information found on these pages to fill out the table on the Bird Populations student sheet. After students have finished their reading, discuss these questions:

  • What questions are the scientists trying to answer? (They are trying to answer questions about movements of bird populations and how and when bird populations change.)
  • Why would it be difficult for just one person to see what a population of birds is doing? What are the obstacles? (It would be difficult for one person to see what a population of birds is doing because that person can usually see only what is happening in his/her neighborhood. Obstacles include not having access to data about bird population movement.)
  • What has the BirdSource Project done to make it easier to study bird populations? What are some of the methods used? (It gathers observations from many observers in many locations over long periods of time. The methods the project uses include bird counts performed by citizen scientists and scientists and the reporting of bird count data directly on the website itself.)
  • What are some of the types of bird movements described? (Some of the types of bird movements are: seasonal migration, irruptions, range expansion or contraction, and static.)


To assess student learning, have them write a short answer essay explaining the differences between the four types of population movements described in the Movements of Bird Populations resource. Students should be able to describe what kinds of patterns might be observed in each type and how observing and studying each pattern gives scientists the evidence they need to understand the movement of bird populations.


Feather Analysis, a Science Update lesson, can be used to extend the ideas in this lesson.

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Lesson Details

Grades Themes Project 2061 Benchmarks