Another rare type of cloud is the noctiluminescent cloud. These are very high clouds that actually shine the way a satellite shines at night when it is going overhead. The light of the sun is still reflecting off the cloud, even though the sun is over the horizon.
Nice information. I remember the National Geographic special on Whooping cranes. These web pages show what happened to the "rocky mountain" flock (which is now gone with the exception of some "snowhill" cranes (cross breed cranes).