Friday Feathers

Are we up for a new quiz? (Won't it be refreshing to see a post from me with no dead, gooey things?)

• 18 subspecies
  
• Nearly global in distribution
• Does not build a nest
• Usually vocalizes only during breeding season
• Was nearly wiped out by a pesticide invented in 1837
• Wears a "helmet"
  

This one isn't hard, my gentle readers.