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| Who am I? (Photo: Dan Irizarry) |
Night-herons are a group of waders named for their nocturnal hunting habits. There are seven extant species of night-heron, with two regularly occurring in the Americas: Black-crowned Night-Heron (Nycticorax nycticorax) and Yellow-crowned Night-Heron (Nyctanassa violacea).
While the Black-crowned has a global distribution (range map), the Yellow-crowned is restricted to the Americas (range map). In the USA, the Yellow-crowned is found mostly in the eastern half of the country, whereas the Black-crowned can be found in some part of every state except Alaska. Both species are prone to wandering outside their core range, especially during migration and post-breeding dispersal.
These two species are unmistakable as adults, but a little trickier to identify as juveniles. Luckily, even their silhouettes are distinctive. This article discusses how to differentiate the species by their proportions and shapes, then describes three categories of plumage you may encounter: adult, juvenile, and a variable "teen" plumage. We also touch on a few other species of herons that might be confused for a night-heron.
The Black-crowned Night-Heron often appears neckless, thanks to a thicker, shorter neck usually curled close to the body. Its head is blocky and large in proportion to its body, and gives an impression of being securely set on the neck. The eye is small or proportional to the bird's head.
Yellow-crowned Night-Herons have a more graceful appearance, due to their thin, tapering neck which is usually held extended up from the body. The head of a YCNH is small relative to its body; it is oval-shaped and connects to the neck in a dainty way. The size and shape of the head are still apparent while this species is resting in a somewhat "hunched" posture. Its eyes appears large, almost bulging.
This distinction isn't foolproof: an alert or hunting BCNH could extend its neck fully, whereas a resting YCNH may curl its neck.
Bill shape
The bill on Black-crowned Night-Herons appears more elongated (Fig. 2). The culmen, the top edge of the upper mandible, is slightly downward-curved, whereas the bottom edge of the lower mandible is almost straight. The bill of a BCNH looks thin in comparison to its square head.
A Yellow-crowned Night-Heron has a stout, bulbous bill. The culmen is more strongly curved, as is the lower edge of the lower mandible. This species appears to have a thick bill in comparison to its petite oval head.
Picking up subtle cues in shape and structure takes some practice. When I'm trying to learn more about a bird, I prefer to identify it using the traits I'm very certain of, then study the traits that are less obvious. In that spirit, remembering the plumages of adults will enable further study, even if you forget everything else in this article. Adults are hard to misidentify.
Adult-plumaged Yellow-crowned Night-Herons have distinctive striped facial markings. The head is black save for two light stripes--one on the crown, and one on the cheek. The rest of the bird is a soft gray with darker-centered, gray-edged feathers on the wings and back. A small yellow plume extends from the crown during breeding season.
Black-crowned Night-Herons use the same color palette, but in a different pattern: dark on top, light underneath. The BCNH has a solid black crown and back, giving it a cloaked appearance. The underside of BCNH looks soft, its creamy white cheeks and throat fading into its gray wings and off-white belly.
Bill color in these species is variable, but adult BCNH tend to have yellower bills. An adult breeding BCNH usually has a fully black bill; in the nonbreeding season it gains a half-yellow lower mandible. In contrast, adult YCNH have mostly or entirely black bills.
Juvenile plumage
The "juvenile plumage" is the first set of feathers a bird grows right after it has hatched. Three characteristics are helpful for identifying individuals that are wearing juvenile plumage: wing/back pattern, chest/throat pattern, and bill color (Fig. 1; Fig. 4). After their first summer, birds molt out of this plumage into successively more adult-like plumages, but retain varying degrees of immature traits (see next section).
Juvenile Black-crowned Night-Herons have large, vertically elongated spots on the back and wing coverts. The shape and size of these spots varies, but they tend to take up a greater area of the feather and average farther up towards the base of the feather, sometimes long enough to touch the next row of feathers. BCNH may have white edging on their wing coverts, but it is usually not as stark as the edging seen on YCNH. Juvenile Yellow-crowned Night-Herons' back/wing spotting is composed of small, creamy-white triangles. These spots are roughly equilateral, i.e., each side of a single "triangle" is roughly the same size. The wing coverts of YCNHs are often edged with contrasting white -- foreshadowing a similar pattern on the adults.
On average, BCNHs' necks have longer, thicker, blurry beige stripes, giving the impression of a lighter neck. YCNHs' necks are darker overall, with smaller, brightly-contrasting white stripes.
Bill color is highly variable, with immatures of both species often showing a yellow-green base to the bill. Young BCNH usually have this feature. The bottom edge of their upper mandible is often lined with bright yellow, green, or orange. This color extends close to the tip of the bill, approximately matching the extent of the coloration on the lower mandible. YCNH average darker bills, and the pale parts look more white than they do yellow or green. The lower edge of the upper mandible is usually not brightly marked; the color extends closer to the tip of the bill on the lower mandible than it does on the upper mandible.
Immature/"teen" plumage
These two species share the interesting trait of not acquiring their "definitive," or adult, plumage for 2-3 years after hatching. These species grow their first streaky brown plumage (Figs. 1, 4; see previous section) soon after hatching in the summer. Starting in their first fall, the birds molt into a "teen" plumage which may be very similar to their juvenile plumage, or may start to show some adultlike features. Each year, the birds molt again, growing successively more adultlike with each molt.
While the Black-crowned has a global distribution (range map), the Yellow-crowned is restricted to the Americas (range map). In the USA, the Yellow-crowned is found mostly in the eastern half of the country, whereas the Black-crowned can be found in some part of every state except Alaska. Both species are prone to wandering outside their core range, especially during migration and post-breeding dispersal.
These two species are unmistakable as adults, but a little trickier to identify as juveniles. Luckily, even their silhouettes are distinctive. This article discusses how to differentiate the species by their proportions and shapes, then describes three categories of plumage you may encounter: adult, juvenile, and a variable "teen" plumage. We also touch on a few other species of herons that might be confused for a night-heron.
Shape and posture
General posture and proportionsOverall, Black-crowned Night-Heron (BCNH, for short) has a compact, hunched appearance, whereas Yellow-crowned Night-Heron (YCNH) gives a more elegant, "upright" impression (Fig. 1). These traits are influenced by the proportions and the posture of each species' neck, head, and body.
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Figure 1: Immature Black-crowned Night-Herons (left) compared to immature Yellow-crowned Night-Herons (right). Sources, clockwise from top left: Nick Shere; Susan Young; Todd Hooe; Stephen R. D. Thompson |
The Black-crowned Night-Heron often appears neckless, thanks to a thicker, shorter neck usually curled close to the body. Its head is blocky and large in proportion to its body, and gives an impression of being securely set on the neck. The eye is small or proportional to the bird's head.
Yellow-crowned Night-Herons have a more graceful appearance, due to their thin, tapering neck which is usually held extended up from the body. The head of a YCNH is small relative to its body; it is oval-shaped and connects to the neck in a dainty way. The size and shape of the head are still apparent while this species is resting in a somewhat "hunched" posture. Its eyes appears large, almost bulging.
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| Figure 2: Adult Black-crowned Night-Heron (above; source unknown) and adult Yellow-crowned Night-Heron (below; by Harvey Barrison). |
In general, BCNH have a thick torso and short legs, whereas YCNH have a slender torso and longer legs. However, length of legs can be a challenging trait to judge on birds walking in water or among tall vegetation. The difference in leg size is apparent in flight. In flight, only the toes of BCNH extend past the tail, whereas in YCNH the toes and part of the tarsi extend past the tail.
Bill shape
The bill on Black-crowned Night-Herons appears more elongated (Fig. 2). The culmen, the top edge of the upper mandible, is slightly downward-curved, whereas the bottom edge of the lower mandible is almost straight. The bill of a BCNH looks thin in comparison to its square head.
A Yellow-crowned Night-Heron has a stout, bulbous bill. The culmen is more strongly curved, as is the lower edge of the lower mandible. This species appears to have a thick bill in comparison to its petite oval head.
Markings
Adult plumage (Fig. 3)Picking up subtle cues in shape and structure takes some practice. When I'm trying to learn more about a bird, I prefer to identify it using the traits I'm very certain of, then study the traits that are less obvious. In that spirit, remembering the plumages of adults will enable further study, even if you forget everything else in this article. Adults are hard to misidentify.
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| Figure 3: Adult black-crowned Night-Heron (left; source) and Yellow-crowned Night-Heron (right; Kenneth Cole Schneider) |
Adult-plumaged Yellow-crowned Night-Herons have distinctive striped facial markings. The head is black save for two light stripes--one on the crown, and one on the cheek. The rest of the bird is a soft gray with darker-centered, gray-edged feathers on the wings and back. A small yellow plume extends from the crown during breeding season.
Black-crowned Night-Herons use the same color palette, but in a different pattern: dark on top, light underneath. The BCNH has a solid black crown and back, giving it a cloaked appearance. The underside of BCNH looks soft, its creamy white cheeks and throat fading into its gray wings and off-white belly.
Bill color in these species is variable, but adult BCNH tend to have yellower bills. An adult breeding BCNH usually has a fully black bill; in the nonbreeding season it gains a half-yellow lower mandible. In contrast, adult YCNH have mostly or entirely black bills.
Juvenile plumage
The "juvenile plumage" is the first set of feathers a bird grows right after it has hatched. Three characteristics are helpful for identifying individuals that are wearing juvenile plumage: wing/back pattern, chest/throat pattern, and bill color (Fig. 1; Fig. 4). After their first summer, birds molt out of this plumage into successively more adult-like plumages, but retain varying degrees of immature traits (see next section).
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| Figure 4. A juvenile-plumaged Black-crowned Night-Heron (left; Dennis Church) has softer neck streaking and larger spots than the precisely-marked juvenile-plumaged Yellow-crowned Night-Heron (right; Tom Benson). Differences in bill color and pattern can be a helpful identification clue as well. |
Juvenile Black-crowned Night-Herons have large, vertically elongated spots on the back and wing coverts. The shape and size of these spots varies, but they tend to take up a greater area of the feather and average farther up towards the base of the feather, sometimes long enough to touch the next row of feathers. BCNH may have white edging on their wing coverts, but it is usually not as stark as the edging seen on YCNH. Juvenile Yellow-crowned Night-Herons' back/wing spotting is composed of small, creamy-white triangles. These spots are roughly equilateral, i.e., each side of a single "triangle" is roughly the same size. The wing coverts of YCNHs are often edged with contrasting white -- foreshadowing a similar pattern on the adults.
On average, BCNHs' necks have longer, thicker, blurry beige stripes, giving the impression of a lighter neck. YCNHs' necks are darker overall, with smaller, brightly-contrasting white stripes.
Bill color is highly variable, with immatures of both species often showing a yellow-green base to the bill. Young BCNH usually have this feature. The bottom edge of their upper mandible is often lined with bright yellow, green, or orange. This color extends close to the tip of the bill, approximately matching the extent of the coloration on the lower mandible. YCNH average darker bills, and the pale parts look more white than they do yellow or green. The lower edge of the upper mandible is usually not brightly marked; the color extends closer to the tip of the bill on the lower mandible than it does on the upper mandible.
Immature/"teen" plumage
These two species share the interesting trait of not acquiring their "definitive," or adult, plumage for 2-3 years after hatching. These species grow their first streaky brown plumage (Figs. 1, 4; see previous section) soon after hatching in the summer. Starting in their first fall, the birds molt into a "teen" plumage which may be very similar to their juvenile plumage, or may start to show some adultlike features. Each year, the birds molt again, growing successively more adultlike with each molt.
The intermediate plumages are similar to the adult plumage, but with a dusky, brownish, dull, or streaky look (Figs. 5, 6). As the bird goes through various molts, its head begins to take on the pattern and coloration of the adult plumage. Each successive molt reduces the appearance of streaks, which also get smaller over time due to wear and tear. Individual birds may acquire different adultlike features in different orders.
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| Figure 5. Three "teen" Black-crowned Night-Herons showing reduced wing spotting and different orders of acquiring adultlike head patterning and unspotted wing coverts (left to right: Len Blumin; Gary Riley; Jerry McFarland) |
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