Question

Homing pigeons can perceive the pattern of polarized light in the sky (which depends on the position of the sun relative to the earth). This enables homing pigeons to orient and navigate home if released in any location. One can reset their biological clock in captivity by artificially controlling the light conditions. If you acclimatize a pigeon to a new lighting cycle with "sunrise" at 6 PM and "sunset" at 6 AM, instead of 6 AM sunrise and 6 PM sunset that naturally occurs, the bird will be clock-shifted by 12 hours within a few days. Suppose you release two birds, a normal bird (N) and a 12-hr clock-adjusted bird (C), 30 km East of their home at 6 AM. In which direction will each bird fly?

• A. Both birds will fly West.
• B. Both birds will fly East.
• C. Bird N will fly West, bird C will fly East.
• D. Bird C will fly West, bird N will fly East.

Hint:

When adjusting biological clocks, animals may perceive the time of day incorrectly, affecting their navigation direction.

Answer 1

The Correct Option is C

Homing pigeons rely on their biological clock and the position of the sun for navigation. The direction they fly depends on their internal clock and how it aligns with the time of day at their release site.
Bird N is the normal bird, whose biological clock is not adjusted. Therefore, it perceives 6 AM as the natural time of release and will use the sun's position accordingly. Since the bird is 30 km East of its home, it will orient West towards its home.
Bird C has been clock-adjusted by 12 hours. This means it perceives the 6 AM release time as 6 PM and uses the sun's position as if it were the evening. Since it is 30 km East, the bird will attempt to fly East, as it mistakenly perceives the sun's position as evening and moves away from its home.
Thus, the correct answer is (C), where Bird N flies West and Bird C flies East.