Every spring, large flocks of dark-colored, long-necked birds make their way across North America: Double crested Cormorants. Due to their distinctive shape, these birds are easy to identify in the marshes and lakes that they inhabit. However, there is another cormorant species that occasionally makes its way north from central and south America that looks incredibly similar to its double-crested relative: The Neotropic Cormorant.
In most places in the United states, with the exception of some southern states, the Neotropic Cormorant is extremely uncommon. For that reason, it pays to know what to look for in order to find a rare species or simply to differentiate them from Double-crested Cormorants in states where the two species regularly overlap.
The first thing to look at is the size and shape. Neotropic Cormorants are shorter and sleeker than Double-crested Cormorants with an average 61cm height, and a wingspan of 102 cm compared to the 70 to 90 cm height and 114 to 123 cm wingspan of the Double-crested Cormorant. In addition to the basic size difference, the Neotropic Cormorant’s tail will appear longer (compared to its body) than the Double-crested Cormorant’s tail. These characteristics are most noticeable in flight when directly compared to the other cormorant species but can also be seen when the birds are perched.
Size can be difficult to determine without a direct comparison to other nearby birds. Fortunately, there are some other field marks that can be used to distinguish these two species. First, note the lores (just above the bill, going from the eye to the bill) on the Double-crested Cormorant. Both juveniles and adults display yellow to orange colored lores. In Neotropic Cormorant, the lores are significantly darker. When comparing these two next to each other, there is actually a significant difference.
Another important area to note on these birds is the gular (which is essentially the upper throat). Both species have orange or yellowish gulars, but the shape is different depending on the species. If you look carefully, you can see that the Neotropic Cormorant has a gular that angles toward the bill in an acute angle. The gular on the Double-crested Cormorant angles far less, and in many instances makes a 90 degree angle.
Another field mark birders regularly use to distinguish these species is the white triangular marking that lines the gular on the Neotropic cormorant. It’s very obvious in adults but less visible in juveniles.
It can be really difficult to make a positive ID based on just one characteristic between these two species. For that reason, it’s best to look at all the field markings. As a whole, an adult Neotropic Cormorant will have a smaller, sleeker stature, a longer tail, dark lores, a gular that acutely angles in toward the bill, and a white triangular marking around the gular. An adult Double-crested Cormorant will be larger and blockier, have a shorter, stubbier tale, brightly colored lores, a gular that is less angled near the mouth, and no white triangle mark around the gular.
A Double-crested Cormorant can be identified by regarding these characteristics:
Brightly colored lores
More obtuse angle where the gular meets the throat
Lack of white around the gular
A Neotropic Cormorant can be identified by the characteristics below
Acute angle where the gular meets the throat
White triangle marking around the gular in adults
With these traits in mind, it becomes much easier to differentiate between these two species. We hope you found this post helpful. Be sure to like and subscribe for more ID tips, and leave a comment below if there are any specific species you would like to see an ID tips about.
Adult Neotropic Cormorant photo by Gary Leavens