In South Lake Tahoe, where I used to live, there are so many pine trees that at various times during the year you will hear a snapping sound overhead and then a pine cone will come crashing down to the ground. I'd hear the "snap" and freeze, never knowing which tree the missile was coming from. I used to feel, at times, that I should be wearing a helmet when I was out working in my yard. Even icicles would sometimes fall with loud, thunderous sounds and I have thought it was odd that just walking outside to the mailbox could feel so dangerous. But those dangers aside, it never, ever crossed my mind that an iguana might fall from the sky.
Maybe Chicken Little might have been taken more seriously had he lived in Naples, Florida.