1427: "GPS Trackers on Birds"

Interesting Things with JC #1427: "GPS Trackers on Birds" – A bird vanishes into the horizon, yet its path is traced across continents. Migration turns from mystery into maps, revealing endurance, surprise, and change in the skies.

Curriculum - Episode Anchor

Episode Title: GPS Trackers on Birds

Episode Number: 1427

Host: JC

Audience: Grades 9–12, college intro, homeschool, lifelong learners

Subject Area: Biology, Environmental Science, Technology in Research, Geography

Lesson Overview

Learning Objectives:

• Define how GPS technology works in tracking bird migration.

• Compare early tracking methods such as banding and radio tags to modern GPS and solar-powered devices.

• Analyze the impact of human development (e.g., landfills, wind farms, urbanization) on bird migration patterns.

• Explain why GPS trackers must be designed with weight and survival constraints in mind.

Key Vocabulary

• Migration (mai-GRAY-shun) — The seasonal movement of animals, such as birds flying long distances between breeding and wintering grounds.

• Telemetry (tuh-LEM-uh-tree) — The collection of data from a distance, such as tracking signals from a bird’s transmitter.

• Solar Panel (SOH-lar PAN-uhl) — A device that captures sunlight and converts it into electricity to power GPS trackers.

• Peregrine Falcon (PAIR-uh-grin FAL-kin) — A bird of prey known for its incredible diving speeds, exceeding 240 mph.

• Satellite (SAT-uh-lite) — An object in orbit around Earth that can transmit signals used in GPS location tracking.

Narrative Core

• Open: Holding a falcon in your hand, light but powerful, a mystery bird that vanishes into the sky.

• Info: Past methods of bird tracking—banding, radar, and radio tags—provided only fragments of migration journeys.

• Details: Advances in GPS and solar technology revealed full migration maps, accurate data, and astonishing discoveries such as nonstop flights across oceans.

• Reflection: Migration routes now reveal how birds adapt—or fail to adapt—to human changes in landscapes and climate.

• Closing: These are interesting things, with JC.

Podcast cover for Interesting Things with JC, episode 1427, titled ‘GPS Trackers on Birds.’ The design features simple bold text with the show’s title and episode number, emphasizing the subject of bird migration and satellite tracking

Transcript

Picture holding a falcon in your hand. It feels light, barely 2 pounds, about 0.9 kilograms, but built for power and speed. For generations people could only guess where these birds went when they lifted into the sky and vanished for months at a time. Then they would return, often to the very same tree. Migration was studied through banding and radar, but the full picture stayed out of reach until satellite tracking gave us far greater precision.

In the 1980s and 1990s, researchers relied on radio tags. Those were bulky, and the only way to follow the bird was by chasing the signal on the ground or even from a plane. You got fragments of the journey, never the whole story. By the early 2000s, things changed. Small GPS trackers were built light enough to ride on the back of a stork or an eagle, often weighing less than an ounce, about 28 grams. The rule is simple, the device should not weigh more than about three percent of the bird’s body weight, so it will not interfere with survival.

The advance was not only the satellites, but also how long the units could run. Early trackers carried heavy batteries that ran down in days. Solar panels changed that. Mounted on the back of the device, they recharge in sunlight, stretching operating life from weeks to many months, and in some cases years when conditions are favorable. On larger birds like eagles, units can run across multiple seasons, storing hundreds and sometimes thousands of positions. Smaller songbirds remain a challenge, since every gram matters, but engineers are working on designs light enough for warblers and even hummingbirds.

GPS works through more than two dozen satellites circling the Earth. Each one keeps time to the microsecond. A tracker compares those signals and fixes a location that is often accurate within tens of meters, and sometimes closer in clear skies. The data is saved on the unit and later relayed through cell towers or satellite links when the bird comes into range. For the first time, researchers could see entire migrations drawn out instead of piecing them together from scattered clues.

The maps revealed things no one expected. A bar tailed godwit, a long beaked shorebird, was recorded flying more than 7,000 miles, over 11,200 kilometers, from Alaska to New Zealand without stopping. Peregrine falcons, nearly wiped out in America during the pesticide years, were tracked diving at speeds over 240 miles per hour, or 386 kilometers per hour. Ospreys, once thought to wander, were shown to follow the same flight lanes every year, as though invisible roads had been carved into the sky. Pelicans too revealed new secrets, with white pelicans tracked moving in great groups from the northern plains of the United States down to the Gulf of America, following rivers and wetlands that guide their way south.

And the maps told another story. Some storks in Europe stopped flying to Africa altogether, spending winters near landfills where food was easy. Expanding cities, new wind farms, and spreading deserts began bending ancient routes. Migration, once thought timeless, now reads like a record of how birds adjust, or sometimes fail to adjust, to a changing world.

When you hear about GPS trackers on birds, it may sound like a story of gadgets and numbers. But in truth, it is about survival, instinct, and the pull to return. The same falcon you held in your hand at the start may vanish into the horizon, yet with this technology, its path can be traced across continents. And even then, the greatest story is not the tracker, it is the bird itself, carving lines through the sky.

These are interesting things, with JC.

Student Worksheet

1. Why is the three percent rule important when designing GPS trackers for birds?

2. Compare how bird migration was studied in the 20th century versus today.

3. What role do solar panels play in extending the lifespan of trackers?

4. What surprising discoveries about migration have been made possible by GPS technology?

5. How does human activity (e.g., landfills, wind farms) alter bird migration patterns?

Teacher Guide

• Estimated Time: 1–2 class periods

• Pre-Teaching Vocabulary Strategy: Introduce GPS, telemetry, migration, and solar power with visuals.

• Anticipated Misconceptions: Students may assume birds follow random routes, or that GPS data is instantly transmitted at all times.

• Discussion Prompts:

  • How does GPS technology change our understanding of animal behavior?

  • Should humans intervene when migration routes are disrupted by urban development?

• Differentiation Strategies:

  • ESL: Provide bilingual glossary and images of birds.

  • IEP: Scaffold learning with sentence starters for discussion questions.

  • Gifted: Ask students to research how satellite tracking is applied to marine animals or endangered species.

• Extension Activities:

  • Map a bird’s migration using real GPS data sets from research organizations.

  • Debate the ethics of attaching devices to wild animals.

• Cross-Curricular Connections:

  • Physics: Explore forces at play in bird flight.

  • Geography: Map migration routes.

  • Ethics/Environmental Science: Discuss the balance between technology and wildlife conservation.

Quiz

1. What is the maximum recommended weight of a tracker relative to a bird’s body weight?
   A. 10%
   B. 3%
   C. 5%
   D. 1%
   Answer: B

2. Which innovation greatly extended the lifespan of GPS trackers?
   A. Smaller batteries
   B. Wind turbines
   C. Solar panels
   D. Satellite upgrades
   Answer: C

3. The bar-tailed godwit was tracked flying nonstop from:
   A. New Zealand to Africa
   B. Alaska to New Zealand
   C. Europe to South America
   D. Canada to Hawaii
   Answer: B

4. How accurate are GPS trackers under clear skies?
   A. Within tens of kilometers
   B. Within hundreds of meters
   C. Within tens of meters
   D. Within 1 kilometer
   Answer: C

5. Which bird was once nearly wiped out in the U.S. due to pesticide use but is now tracked diving at over 240 mph?
   A. Osprey
   B. Peregrine Falcon
   C. Stork
   D. Godwit
   Answer: B

Assessment

1. Explain how GPS tracking has changed scientific understanding of migration compared to older methods like banding and radio tags.

2. Evaluate how human activity is influencing migration routes, providing at least two examples from the episode.

Rubric (3–2–1):

• 3 = Accurate, complete, thoughtful responses using examples from episode

• 2 = Partial or missing details, limited examples

• 1 = Inaccurate or vague explanation

Standards Alignment

NGSS (Next Generation Science Standards)

• HS-LS2-6: Evaluate the impact of human activity on ecosystems, specifically bird migration and adaptation.

• HS-ESS3-1: Construct explanations for how natural systems are influenced by human activity, such as urban development.

CCSS (Common Core State Standards – ELA)

• CCSS.ELA-LITERACY.RST.11-12.2: Determine central ideas of a scientific text and summarize key details.

• CCSS.ELA-LITERACY.WHST.9-12.2: Write informative texts that explain processes such as GPS tracking.

C3 (College, Career, and Civic Life Framework for Social Studies)

• D2.Geo.2.9-12: Use geographic data to evaluate human-environment interactions, such as altered migration routes.

International Equivalents

• UK AQA A-Level Biology (3.7.4 Populations in ecosystems): Understand adaptations and the effect of human activity on species distribution.

• IB Biology (Topic 4.3): Evaluate how human activity impacts ecosystems and species survival.

• Cambridge IGCSE Geography (Unit 3.1 Migration): Study patterns of migration and environmental influences.

Show Notes

In this episode of Interesting Things with JC, listeners explore how GPS technology revolutionized the study of bird migration. Once reliant on banding and bulky radio tags, researchers now use lightweight, solar-powered devices to trace entire journeys across continents. This technology has revealed astonishing feats, such as the nonstop flight of the bar-tailed godwit from Alaska to New Zealand, and it has shown how human activity alters migration paths. In the classroom, this topic bridges science, geography, and ethics, providing students with a window into how technology deepens our understanding of wildlife while also raising important questions about conservation in a changing world.

References

• BirdLife International. (2023). Satellite tracking of birds: new insights into migration. Retrieved from https://www.birdlife.org

• Cornell Lab of Ornithology. (2023). Bird migration and tracking technologies. Retrieved from https://www.birds.cornell.edu

• U.S. Geological Survey. (2022). Tracking migratory birds with satellite technology. Retrieved from https://www.usgs.gov

• National Audubon Society. (2023). How GPS trackers changed bird migration science. Retrieved from https://www.audubon.org