Bittern
/ˈbɪtərn/
Definition 1 of 1
Pro Tip 1/3Habitat Specific
Used to refer to birds in marshy or reedy wetlands, not just any bird. 
The nature reserve is an excellent place to see a bittern in its natural habitat.
Pro Tip 2/3Elusive Bird
Implies the bird is often difficult to see or find due to its secretive behavior. 
Despite searching all day, the bittern remained elusive.
Pro Tip 3/3Mistaken Identity
Avoid confusing 'bittern' with more common birds; it's a specific type of heron. 
At first glance, I mistook the crane for a bitern, but then I noticed the difference.