kevin's id tips

kevin's id tips

Black-crowned & Yellow-crowned Night-Herons, immatures

Immature Yellow-crowned Night Heron (L) and immature Black-crowned Night Heron (C) - American Bittern (R)

Two night-herons share somewhat similar body shapes and structural features and have comparable juvenile/immature plumage for most of their first year.  With careful study, you will notice subtle to obvious differences in body and bill shape as well as plumage features. Juvenile plumage may be referred to as immature plumage after August due to a slightly different appearance caused by feather wear, even though the feathers are the same.                                                                                                       

Physical Features:

Yellow-crowned has a longer neck and more slender body, which combined with a smaller head and different bill shape creates a different profile than Black-crowned. Black-crowned has a stockier body and thicker, shorter neck. Its bill is also heavier, but more importantly, different in shape. 

 

Black-crowned’s thick-based bill tapers to a fine point with a slightly decurved upper mandible and straight lower culmen. This differs from juvenile Yellow-crowned’s stocky bill, whose upper culmen and lower mandible are similar in shape. With careful comparison, Yellow-crowned’s different bill shape combined with a smaller head becomes a reliable and recognizable physical impression, even with silhouetted birds. 

 

In comparison to both night-herons, American Bittern is much larger in size and has a noticeably longer neck and bill. It also has a thin head that seems to be an extension of its neck, unlike both night-herons that have defined head shapes. 

 

Plumage and Bare Parts Details:

Immature Black-crowned’s bill is mostly yellowish in color, especially the lower mandible, while immature Yellow-crowned has a mostly blackish-gray bill that is often washed whitish by salt in coastal locations. Young juvenile Yellow-crowned’s evenly proportioned bill has a yellowish lower mandible base during its first few months of life, similar to Black-crowned, so care should be taken when evaluating this detail during summer months. 

 

Subtle plumage differences are helpful in separating these two birds. Black-crowned is browner than the grayish-toned Yellow-crowned, and has large white spots on the wing coverts compared to finer ones on Yellow-crowned.  Black-crowned also has broad, blurry streaks on the underparts compared to narrow, more defined spots in Yellow-crowned. 

 

American Bittern shows slight plumage similarities to both juvenile night-herons and is found in the same wetland habitats. It has a uniform brownish crown and back, buff cheek, and complex, fine markings on its wing coverts. Underparts and neck are more heavily streaked with greater pale background than both immature night-herons, and a yellow iris differs from orange ones in night-herons.