Trumpeter Swan Population Decline and Restoration

Trumpeter swans were once common in Iowa but by the late 1800’s the Trumpeter swans were missing from the Iowa habitat. They were missing for nearly 100 years after most of their wetland habitat was drained for farmland and the swans were hunted for their prized feathers and served as a food source during the time of settlement. These swans experienced near extinction in the lower 48 states. Almost 20 years after the Iowa DNR began efforts to reintroduce the Trumpeter swan population in Iowa, the program is succeeding. Swans tend to settle in areas with high water quality and strong plant growth to support their diet. Now, 17 states (from Colorado to Virginia and two Canadian provinces) report seeing swans that were numbered and released from Iowa.

Guiding Question

• What factors caused the loss and revitalization of the Trumpeter swan from the Iowa landscape?

Probing Questions

• How do the Trumpeter swans serve as evidence that changes to physical components of an ecosystem affect populations? 
• If a person saw a swan on a body of water, what might that person assume about the water quality of a body of water?

Classroom Suggestions

Students could:

• Brainstorm the impact of humans on the physical environment in Iowa.
• Watch the video (or research other examples) to create a claim, evidence, and reasoning about Trumpeter swans.
  • In their claim, students include the idea that changes to physical components of an ecosystem can affect the populations living there. 
  • Support their claim with evidence (e.g., evidence from data, scientific literature) needed for supporting the claim, including evidence about: 
    • Changes in the physical or biological components of an ecosystem, including the magnitude of the changes (e.g., data about rainfall, fires, predator removal, species introduction). 
    • Changes in the populations of an ecosystem, including the magnitude of the changes (e.g., changes in population size, types of species present, and relative prevalence of a species within the ecosystem). 
    •  Evidence of causal and correlational relationships between changes in the components of an ecosystem with the changes in populations. Students use multiple valid and reliable sources of evidence
• Connect the appropriate evidence to the claim and construct an oral or written argument about the causal relationship between physical and biological components of an ecosystem and changes in organism populations, based on patterns in the evidence.
• Research and discuss the importance of wetlands and water quality.

Related Resources

• Canadian Wildlife Federation | Trumpeter Swan: This website provides general background information about the Trumpeter Swan.
• Iowa Department of Natural Resources (DNR) | Trumpeter Swan: Read more about about the swan in Iowa as well as find information about how you can help with swan reporting.
• Iowa Department of Natural Resources (DNR) | Wildlife Species Restoration: Learn more about wildlife restoration efforts in Iowa, including those for the Trumpeter swan.
• Iowa State University: College of Agriculture and Life Sciences | Track a Trumpeter: Explore this article and videos about Trumpeter Swan banding and details about the goals of the 1993 IDNR restoration program.
• Association of Fish and Wildlife Services | Let’s Talk Turkey: Create a timeline of historical use of turkeys and compare to the story of the trumpeter swan.