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Activity: Alert and Escape Behavior
NGSS Science and Engineering Practices
NGSS Crosscutting Concepts


  • Table 5.8
  • Binoculars
  • Three small colored marking objects such as erasers or cable ties
  • Transect tape
  • Calculator
  • Pencil
  • Clipboard



  1. Predict some of the initial behaviors that you expect birds at your field site to be doing when you arrive.
  2. Predict what type of alert behaviors you may observe as you approach a bird. An animal might be considered alert if it detects a predator or prey.
  3. Predict what type of escape behaviors you may observe as you approach a bird.


Fig. 5.55. (A) Hold the pencil vertically with the sharpened tip aligned with the treetop.

Image by David Lin

Fig. 5.55. (B) Rotate the pencil 90 degrees pivoting at the base of the tree.

Image by David Lin


  1. Practice estimating the height of tall objects, such as a tree or other structures birds may be roosting in using the pencil method. Use Fig. 5.55 as a reference.
    1. Find a tree that is taller than each student in your group.
    2. Stand away from the tree such that you are at least standing further away from the tree than it is tall.
    3. Hold the pencil upright in front of you while facing the tree with your arm outstretched. The sharpened pencil tip should point skyward.
    4. Position the sharpened pencil tip so that it appears even with the top of the tree from your viewpoint (Fig. 5.55 A).
    5. Carefully rotate the pencil 90 degrees pivoting around the base of the tree (Fig. 5.55 B). The pencil tip should now be pointing to the left or right parallel to the ground.
    6. Direct your partner to stand at the base of the tree and then walk to the spot where your pencil tip is pointing (Fig. 5.55 B). Your partner will be standing at a distance from the base of the tree that is equal to the height of the tree.
    7. Using the transect tape, measure the distance from the base of the tree to where your partner is standing. Record this distance as the tree height.
  2. Refer to the diagrams in Figure 5.56 illustrating alert and escape distances. Determine how your group will distinguish alert behavior and escape behavior and how to measure these distances for a bird on the ground.


Fig. 5.56. Alert and escape distances for a bird on the ground

Image by David Lin

Fig. 5.57. Alert and escape distances for a bird roosting in a tree

Image by David Lin

  1. Determine an equation to solve for the alert distance and the escape distance for a bird above the ground in a roost (Fig. 5.57) using the height of the bird and the horizontal ground distances.
  2. Find a location where one or more species of birds are present.  Keep in mind that birds are generally most active and visible in the morning and late afternoon. Note: Be sure the area is safe to walk in.
  3. Designate an observer and a walker.
    1. The observer will observe bird behavior, using the binoculars if necessary.
    2. The walker will be in charge of walking a path towards the bird and dropping marking objects.
  4. Find a bird at your field location, either on the ground or roosting, that is a sufficient distance away that it has not noticed you.
    1. Record the type of bird in Table 5.8. A description is acceptable if you are unsure of the species.
    2. Record the location of the bird in Table 5.8.
    3. Predict the alert and escape distance in meters and record in Table 5.8.
  5. Observe the bird.
    1. The observer should remain still and keep watch of the bird’s behavior using the binoculars if necessary. 
    2. Record the initial behavior of the bird in Table 5.8.
    3. The walker should walk at a constant steady pace in a straight line towards the bird holding three markers.
    4. When the bird exhibits alert behavior, the observer should instruct the walker to drop the first marker. Note: the walker should continue walking towards the bird at the same pace.
    5. When either the observer or the walker sees the bird escape, the walker should drop the second marker.
    6. Record the alert and escape behaviors in Table 5.8.
    7. Place the third marker at the location where the bird was before it escaped. If the bird was roosting in a tree or other object, place the marker on the ground directly below where the bird was.
  6. Using the transect tape, measure the over the ground distance from the third marker (i.e. the bird’s location) to the first and second marker.
  7. If the bird was in a roost, use the pencil method outlined in step 4, to calculate the height of the bird’s roost.
  8. Using the equations defined in step 5, calculate alert and escape distance and record in Table 5.8.
  9. Repeat steps 8-–12 for at least two more birds.


Activity Questions
  1. Did the predicted behaviors match the observed behaviors for initial, alert, and escape behaviors? Explain.
  2. What are some examples of alert and escape behaviors for marine, aquatic, and terrestrial birds? How might they differ?
  3. Were the alert and escape distances similar? Did they vary between different birds?  Explain.
  4. How might habitat affect the alert and escape distances of birds in general? Of the birds you were observing?
  5. Many birds interact with humans frequently because they live in the same locations or they are fed purposefully or by food left behind. How might this affect the alert and escape behaviors and distances?
  6. Imagine you are designing a bird sanctuary. You want to put a walking path through the sanctuary such that visitors would not disturb the birds. Based on your observations, how far away would you suggest setting up the path from the primary bird habitat?
  7. Scientists occasionally notice that larger birds escape sooner than smaller bird species.
    1. Do you have any evidence to support or refute this? Explain.
    2. What biological reasons might account for large birds escaping sooner?
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.