(Regulus calendula)
The ruby-crowned kinglet (Regulus calendula) is a very small passerine bird found throughout North America.It is a member of the kinglet family.The bird has olive-green plumage with two white wing bars and a white eye-ring.Males have a red crown patch,which is usually concealed.The sexes are identical (apart from the crown),and juveniles are similar in plumage to adults.It is one of the smallest songbirds in North America.The ruby-crowned kinglet is not closely related to other kinglets,and is put in its own subgenus,Corthylio.Three subspecies are currently recognized.