(Encyclopedia) rhythm, biological, or biorhythm, cyclic pattern of physiological changes or changes in activity in living organisms, most often synchronized with daily, monthly, or annual cyclical? (Encyclopedia) migration of animals, movements of animals in large numbers from one place to another. In modern usage the term is usually restricted to regular, periodic movements of populations away? (Encyclopedia) bird, warm-blooded, egg-laying, vertebrate animal having its body covered with feathers and its forelimbs modified into wings, which are used by most birds for flight. Birds compose? What's behind the outbreak in Louisiana? by David Johnson Related Links More About Killer Bees and TermitesMore Natural DisastersCentral ParkPersonal HealthDisease &?