Teacher sheet · Ages 15–16 · about 45–50 minutes
Fuel, speed and navigation on the move
Lesson page: echoesof.science/school/migration/ages-15-16/ · Pupil worksheet: echoesof.science/school/migration/ages-15-16/print/
Learning aims
- Explain the triggers and physiological preparation for migration.
- Calculate speeds and rates from migration data, with attention to units and rounding.
- Describe and evaluate classic navigation experiments.
- Relate magnetic field geometry to how animals may sense direction and position.
- Distinguish types of evidence: tracking, ringing and controlled experiments.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: how would you prove that a bird uses the stars to navigate? |
| 10 min | Read the text; speed calculation for E7. |
| 20 min | Field mapping practical and discussion of axis and dip. |
| 5 min | What kind of evidence? game. |
| 5 min | Quiz and evaluation. |
Materials for the experiment
- Bar magnet (poles marked)
- Plotting compasses (at least 4)
- A3 paper and pencil
- A magnetic compass for the room
- Protractor
- Optional: a magnetometer app on a phone or a dip needle
Safety: Keep magnets away from phones, bank cards and computers. Do not let strong magnets snap together near fingers. Handle a dip needle gently.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| Birds sense north like a compass needle. | Experiments suggest they sense the axis and dip of the field, not its polarity. |
| Migration is triggered by cold weather. | The main cue is changing day length. |
| A single tracked bird proves what the whole species does. | Individuals differ; tracking data need many birds and other evidence such as ringing. |
Worksheet answers
- 8 days = 192 h; 11,700 ÷ 192 ≈ 61 km/h. The reported figure is lower because 'about 8 days' is rounded (the flight ran from 29 August to 7 September), the distance is approximate, and the miles were converted.
- Fat is the most energy-dense fuel, giving more than twice the energy per gram of carbohydrate or protein, so it is the lightest way to carry energy; e.g. songbirds up to 50% fat, a godwit's mass can more than double.
- E.g. Kramer 1951: mirrors moved the apparent position of the sun; starlings shifted their direction; birds use a sun compass linked to an internal clock. Or Emlen 1967 / robins in a turned magnetic field.
- It could tell the line (axis) of the field and its dip angle, and might estimate latitude from field strength; it could not tell which end of the field points north.
Quiz answers
- A humpback swims about 3,000 miles in 28 days. Its average distance per day is about… 107 miles. 3,000 ÷ 28 ≈ 107 miles per day.[5]
- A tracking tag must be at most 3% of body mass. What is the smallest bird that can carry a 25 g tag? About 830 g. 25 ÷ 0.03 ≈ 833 g.[7]
- An Arctic tern flies about 50,000 km a year. What is its average distance per day? About 140 km. 50,000 ÷ 365 ≈ 137 km per day.[1]
- What did Emlen's 1967 experiments with indigo buntings show? Young birds learn north from the rotation of the stars. Birds raised without star rotation oriented randomly.[2]
- What is the main cue that triggers migration? Changing day length. Temperature and food also play a part.[1]
- Why do migrating birds store fat rather than carbohydrate? Fat stores more than twice the energy per gram. Fat is the most energy-dense fuel.[7][3]
Going further
Use E7's data to estimate energy use: look up the energy stored per gram of fat in your textbook, assume a mass of fat used, and calculate the bird's average power in watts during the 8-day flight. Discuss which numbers you would need to measure to make the estimate reliable.
Sources used in this lesson
- [1] The basics: how, why, and where of bird migration (Cornell Lab of Ornithology (All About Birds)): reliability High
- [2] The basics: how birds navigate when they migrate (Cornell Lab of Ornithology (All About Birds)): reliability High
- [3] Bird migration (British Trust for Ornithology (BTO)): reliability High
- [4] Monarch butterfly migration and overwintering (USDA Forest Service): reliability High
- [5] Humpback whale (NOAA Fisheries): reliability High
- [7] Flight of the Kuaka: a godwit makes the longest nonstop flight ever recorded (Cornell Lab of Ornithology (All About Birds)): reliability High
- [8] Crossing the ultimate ecological barrier: evidence for an 11,000-km-long non-stop flight from Alaska to New Zealand (U.S. Geological Survey (publication record, The Condor, 2005)): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/migration/sources/
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