The first possible recorded incident of animals falling from the sky was a shower of frogs in ancient Greece 200 BC. Since then, numerous similar events have been reported, and there were probably similar occasions before that. Such reports continue to come in from in all parts of the globe right up until today and are prime fodder for mass media in need of filler stories, devotees of the supernatural and apocalypse predictors.
How Does it Happen?
Tadpoles in Japan, spiders in Argentina, worms in Louisiana -- all these and many others have apparently materialized out of thin air and come to earth in front of witnesses, but only the descent and arrival were witnessed; the pickup and delivery systems remain mysterious. Tornados, those violent spinning winds that wreck buildings and drive straws through tree trunks, are often blamed for picking up hapless small fry and carrying them off like Dorothy in "The Wizard of Oz." Since so many of the surprise arrivals have been water-dwellers, such as fish, crabs, frogs and snails, waterspouts (tornados that form over water) are credited with sucking them up and depositing them far afield.
Some sky-fallen critters have managed to arrive alive, but DOA is more common, and the causes of death are varied. A deluge of starlings that dropped from the firmament into an English village in 2010 were diagnosed with oxygen deprivation in a flock that lost its orientation and flew too high. Frozen fish showered the Australian desert hamlet of Lajamanu for two days in 2010, the third such deluge in 30 years. A 2-foot leopard shark was alive when it landed on a golf course in San Juan Capistrano, California, in 2012, but it showed puncture wounds indicating it had been caught and then dropped by a fishing bird, such as an osprey. The Tennessee cow that apparently tried to fly off a 200-foot cliff in 2007 and landed on a moving minivan didn't survive the experience, but the lucky driver did.
How likely are you to get beaned by an animal plummeting out of the blue? Since these events have been happening for so long, it seems safe to say they'll probably continue. Is it possible to predict them? They've happened in foul weather and fair, heat and cold, and seem to be truly random events. Unless science delves into the mystery and pinpoints the cause and the agent, we can't know where flying fauna come from, or why, or when. If you hear "thump-thump" instead of "pitter-patter" on the roof, better check carefully before venturing out.
Possible solutions to personal danger could be: A) staying indoors at all times, or B) carrying an umbrella everywhere you go. If you elect the latter and it starts to rain pennies from Heaven instead of the proverbial cats and dogs, you can turn it upside down and get rich.