I think BerrieK has the right idea. I have seen crows carry off stones and bones.
However I have seen in Arizona photos of "soft" meteorite landings.
Part of the article from:
http://www.physics.smu.edu/jcotton/ph1311/ch04a.htm
The first one is called a "find" and the second is called a "fall." The term "fall" implies that the meteorite is recovered soon after it was observed falling. Funny thing - finds are about 80% irons while falls are about 95% stones. So 95% of what falls in stone but 80% of what gets found is iron! This is actually not mysterious. For a meteorite to get found, it must look different from the rocks in the area. An iron meteorite is almost guaranteed to do that. A stone meteorite can look a lot like any other rock, and someone not familiar with the appearance of meteorites will likely miss it.