Small, Chestnut-Brown Bird of Prey
This page is the CodyCross answer for the clue below from Physics, Group 1891, Puzzle 3 (Principle of Relativity).
Question is: Small, Chestnut-Brown Bird of Prey
and the answer is: KESTREL
Word Meaning:
KESTREL — Any of various small falcons of the genus Falco that hover while hunting.
Definitions from Wiktionary.