Puffin Puffin
The bird you are thinking of is a SWAN.
ter
There is no specific species of bird that ends with "tar."
The dodo is an extinct bird with just three letters in its name.
Bird
Rail
tanager
Puffin Puffin
If the s here indicates a plural, then rails are wading birds that have a 5-letter name ending in s. (The word rail is obviously a 4-letter word.)
pelican
redwing
joerw
Walbeb
The bird you are thinking of is a SWAN.
Swift
Goldfinch, Chaffinch or Bullfinch.