Using Empirical Data in the Classroom: Raptor Migrations!

Students will

1. Analyze real scientific data from a short visualization clip to form logical hypotheses about what drives the migration patterns of raptors.
2. Describe and explain the connectedness of organisms within and across ecosystems.
3. Illustrate how primary productivity is the foundation of all food webs and how seasonal changes in primary productivity influence the behaviors of higher order consumers.

1. If you will be using it, print out one Student Worksheet per student.
2. Test the video quality on your school's internet connection. Note that you can click the Settings cog in the footer to adjust the Quality to up to 1080HD, and you can also toggle on Full Screen.

Video: Why Do Birds Migrate? (Educator Version) | California Academy of Sciences

https://www.youtube.com/watch?v=ZjIqPigm9Ps

Prior to this exercise, students should have some basic, but not necessarily extensive, knowledge about ecosystems, ecology, and seasonality. This activity can be used either as an introduction to a unit on ecosystems, ecosystem dynamics (trophic structures and interactions), and productivity, OR it can be used as an activity in the middle or at the end of the unit to give students practice applying their knowledge and making connections between concepts.

In this activity, the teacher will show students a short visualization clip (in segments) of raptor migrations between North and South America and will guide students in constructing hypothesis and logical explanations using empirical scientific data. Students will reflect upon and engage in discussions with their classmates after watching each clip segment, as outlined in the Activity below.

The numbered questions listed in italics under the Activity outline below are the same questions that are on the Student Worksheet provided.

• Teacher Tip: If you do provide each student with a Student Worksheet, instruct them to cover up all of the questions other than the one(s) they are answering so that information isn't revealed too early!

Give your students a few minutes to reflect individually on their student worksheets OR in their notebooks after watching each clip segment, then discuss the questions as a class.

The ultimate goal of this exercise is for the students to be able to analyze, interpret, and integrate the data presented in this science visualization clip to describe the seasonal migration habits of ospreys and turkey vultures and what might be driving them. The goal is also for them to be able to describe how we can use empirical data to gain knowledge about the natural world.

You can wrap up this activity with the following two student questions, or extend it with any of the extensions listed below.

9. Write a brief summary of the information presented in the video clip. How did your preexisting knowledge help you with forming hypotheses throughout this exercise?

10. The scientific data you analyzed in this video clip (raptor migration patterns and carbon absorption) are what we call 'empirical' data, or data/knowledge that we've acquired through experimentation and observation. How do you think scientists obtained the empirical data used in this visualization? What other empirical data might be useful for further analyzing the migration habits of these two raptors?

Migration patterns of species can provide valuable insight into the stability of various ecosystems. The migration patterns of ospreys and turkey vultures throughout North and South America are illustrated in this video. Nearly all of the osprey and turkey vulture populations shown in this video follow the same migratory patterns, regardless of their specific breeding and wintering grounds. These raptors nest and breed in their northern most location during the spring and summer months. As the seasonal changes of fall approach, raptors begin their annual southern migration to their respective wintering grounds. After approximately five months in their winter locations, ospreys and turkey vultures begin to migrate northward to their original nesting grounds (Shane, 2014). While scarcity of food during the winter season is often considered the primary cause of southward raptor migration in the fall, this video provides a closer look at the relationship between raptor migration, food availability, and net primary productivity (NPP). Specifically, it illustrates the connection between primary producers and higher order members of a food chain/web. While raptors don't feed directly on primary producers, they do feed on the primary consumers who rely on the producers.

In addition to raptor migration patterns, the video illustrates changes in carbon absorption on land and in water, referred to as net primary productivity (NPP). Through photosynthesis, plants take in CO₂ and convert carbon into sugar molecules (carbohydrates) using water and energy from the sun (NASA, 2015). This process occurs in land plants, in algae, and in other primary producers of our oceans, such as microscopic phytoplankton. Although CO₂ is broken down during photosynthesis, some CO₂ is released back into the atmosphere as plants respire. The amount of CO₂ taken in by vegetation during photosynthesis minus the amount of CO₂ put out during respiration equals NPP, or the total amount of CO₂ absorbed by plants (NASA, 2015):

CO₂ taken in - CO₂ respired out = Total CO₂ absorbed by vegetation = Net Primary Productivity (NPP)

The chemical reaction by which plants produce complex food molecules requires an energy input from sunlight to occur. On land and in the ocean, the availability of light from the sun limits the amount of energy plants can use for photosynthesis, in turn limiting the amount of CO₂ they are able to take in. The seasonal variability of light and its effect on net primary production is illustrated in this video. An increase in NPP is reflected in both the Northern and Southern Hemispheres during their respective summer months. An increase in the availability of sunlight allows plants to photosynthesize at a faster rate, increasing the amount of CO₂ being absorbed from the atmosphere and raising NPP (NASA, 2015).

As these plants take in carbon for food and fuel, they continue to grow and eventually become a food source for consumers higher on the food chain (National Wildlife Federation, 2015). All successful food chains must begin with producers, such as plants or algae that can synthesize carbohydrates through solar and chemical energy. As apex predators, raptors generally do not rely directly on plant matter as a food source, but the fish, small mammals, and prey birds they feed on do. The more producers available for fish, small rodents, and prey birds to consume means an increase in the amount of food available to osprey and turkey vulture communities.

This video illustrates the correlation between raptor migration patterns and carbon absorption on land and in water. Raptor flight patterns are aligned very closely with seasonal changes in NPP. As winter approaches and NPP decreases in their breeding locations, ospreys and turkey vultures migrate south in search of food where NPP is higher during these months.

• Principle III: Natural systems proceed through cycles that humans depend upon, benefit from and can alter.
  • Concept a: Students need to know that natural systems proceed through cycles and processes that are required for their functioning.

Food Webs and Bioaccumulation. (n.d.) Retrieved May 2015 from http://www.nwf.org/Wildlife/Wildlife-Conservation/Food-Webs.aspx

Global Maps: Chlorophyll and Net Primary Productivity. NASA Earth Observatory. Retrieved May 2015 from http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MY1DMM_CHLORA&d2=MOD17A2_M_PSN

Global Maps: Net Primary Productivity. NASA Earth Observatory. Retrieved May 2015 from http://earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MOD17A2_M_PSN

Net Primary Productivity (1 Month- TERRA/MODIS). NASA Earth Observations. Retrieved April 2015 from http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MOD17A2_M_PSN

Raptors of the World. Raptor Research Foundation. Retrieved July 2015 from http://www.raptorresearchfoundation.org/education/raptor-world

Shane, Ken (2014). Osprey Expert Talks About Migratory Patterns of Raptor. The Jamestown Press. Retrieved July 2015 from http://www.jamestownpress.com/news/2014-04-24/News/Osprey_expert_talks_about_migratory_patterns_of_ra.html