Gustav Kramer was among the first to determine that birds migrating during the day use the sun as a navigational cue by noting that caged starlings (Sturnus vulgaris) oriented in the normal migratory direction
A) as long as the sun was visible.
B) but only when they were released to fly normally.
C) unless the "sun" was being produced by a mirror.
D) when sky was overcast.

Question

Quizplus · Accepted Answer

Gustav Kramer's experiments demonstrated that caged starlings oriented in their normal migratory direction as long as the sun was visible, indicating that they use the sun as a navigational cue.

Gustav Kramer Was Among the First to Determine That Birds