Sentence:  Understandably, birders in the U.S. are advised to carefully distinguish <WSD>Ruddies</WSD> from the usually more-expected Common Ground-Doves [...]. (Brightly-colored, pinkish adult male Common Ground-Doves have been misidentified as male <WSD>Ruddies</WSD> on several occasions, however.) Unless the fortunate birder happens upon a Ruddy Ground-Dove amongst a flock of sparrows, it will often be necessary to sort through innumerable Inca Doves. 
Meaning of the word marked with <WSD> tags:  A ruddy ground dove.