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Biology 312: February 17, 2003
Orientation, Navigation and Migration
NOTE: In addition to your lecture notes, Reserve Reading 2, the Navigation video viewed
in lab and your text will all be useful in answering these questions.
Study questions (handout previous distributed)
1.
Define migration.
2.
Describe how different migratory patterns occur over different timespans (daily, etc…),
and provide examples.
3.
List several different migratory patterns (in terms of changes in position), and provide
examples of each.
4.
What are some of the longest migrations known?
5.
Describe both the costs and benefits (adaptive value) of migration. Be sure you understand
how a cost can be incurred during migration itself for a particular factor (such as energy
expenditure) but that overall, migration can lead to a net benefit for that same factor.
6.
What role does a compass play in migration? What role does a map play in navigation?
7.
List as many cues as you can that could potentially be useful to an animal in either the map
sense or the compass sense.
8.
What type of experiments did William Keeton perform to determine whether pigeons could
detect particular cues? Describe the basics of these experiments. According to the results
of these experiments, what cues were pigeons able to detect?
9.
Understand how a sun compass works, and how clock-shifting experiments were used to
show that pigeons were following a sun compass to navigate back to their home loft.
10.
Answer the following questions related to the sun compass and clock-shifting. Assume
you are in the Northern Hemisphere unless specifically stated otherwise. You will
probably find making sketches helpful to answer these questions.
a.
b.
A normal (not clock-shifted) pigeon is driven to a site due south of its home loft, and
released at noon. In which compass direction is home? Where will it keep the sun’s
position to orient itself directly to home?
A pigeon is clock-shifted back by six hours (so it thinks it is six hours earlier than it
really is) and is, like the above bird, driven due south of its home loft and released at
noon. Where will it keep the sun’s position (relative to itself) to orient itself to
where it thinks home is? In which compass direction will it actually orient/fly?
c.
A pigeon is clock-shifted forward by six hours (so it thinks it is six hours later than it
really is) and is, like the above birds, driven due south of its home loft and released
at noon. Where will it keep the sun’s position (relative to itself) to orient itself to
where it thinks home is? In which compass direction will it actually orient/fly?
d.
A normal (not clock-shifted) pigeon is driven to a site due east of its home loft and
released at 6 AM. In which compass direction is home? Where will it keep the
sun’s position to orient itself directly to home?
A pigeon is clock-shifted forward by six hours (so it thinks it is six hours later than it
really is) and is, like the above bird, driven due east of its home loft and released at 6
AM. Where will it keep the sun’s position (relative to itself) to orient itself to where
it thinks home is? In which compass direction will it actually orient/fly?
e.
f.
A normal (not clock-shifted) pigeon in the southern hemisphere is driven to a site
due west of its home loft, and released at noon. In which compass direction is
home? Where will it keep the sun’s position to orient itself directly to home?
11.
While the sun compass was emphasized in the pigeon studies, do we know whether
pigeons have a map sense as well? Explain.
12.
Explain the concept of an “odor map”, which some scientists argue could be the basis for
the map sense in pigeons.
13.
What cues are sea turtles likely to be using to navigate? Back up your answer with
experimental evidence (see Reserve Reading 2).
14.
Describe the experiments which showed that indigo buntings use the stars to navigate on
their migratory journey. What experience, if any, was required for them to orient to the
North Star (Polaris)? How did Stephen Emlen get them to orient to Betelgeuse rather than
Polaris? How did the researchers determine which way they were orienting? Explain
whether this behavior is innate, learned, or a combination of the two. (If a combination,
what about the behavior is innate and what is learned.)
15.
Can the indigo buntings still navigate if the pole star is blocked but other stars in the same
region of the sky are visible? Explain?