There, Their and They're

 

I stepped outside yesterday to fill the water dish.   Most of the neighborhood critters usually stop by for a drink.  As I poured fresh water into the bowl, the crows were yelling at me.  I went ahead and assumed they were thanking me.

I tried to understand how it is they communicate with each other when it all sounds the same.  Caw! Caw!  I can’t detect any deviation, no inflections or change in pitch or volume.  Every yell sounds exactly the same.  How strange is that?