How do I fix certain parts of my character not moving with the armatures placed? So this is my first somewhat decent looking  character,, and I am trying to place armatures inside to see what I can do with him. However, once I finished doing what I thought would work, this happened. Can anyone help me and tell me what I did wrong? I can post the .blend file somewhere so you guys can get a better look if you need. 

.blend file link: https://www.dropbox.com/s/95lo4tixzu795yn/NatureFile.blend?dl=0

Update: 

Added link to .blend file
it is a weight paint error , i've checked the file and the part that is not moving has no parent , So 
-re-parent the whole mesh with "envelope or automatic weight " 
if it doesn't work :
-go to weight paint mode and do it manually
or :  
-add theme to the vertex group with the bone name