Cormorants are medium-to-large sized waterbirds that live near both fresh and saltwater habitats. There are about 40 different species of cormorants found throughout the world. Some key features that characterize cormorants include their long necks, hooked bills, webbed feet, and their ability to dive from the surface to catch fish and other prey. When looking for birds that are similar to cormorants, we can examine species that share common anatomical features, behaviors, habitats, and evolutionary relationships. In this article, we’ll take a closer look at some of the birds that bear resemblance to cormorants.
Anatomy and Appearance
Several types of waterbirds share the distinct anatomical features of cormorants. Most similar are the anhingas. Like cormorants, anhingas have slender bodies, long necks, pointed bills, and webbed feet. When swimming, both cormorants and anhingas swim low in the water with just their sinuous necks sticking up, giving them a snake-like appearance. Anhingas are nearly indistinguishable from cormorants when seen from a distance.
Other aquatic birds with comparable anatomy include darters, gannets, boobies, and some herons. Darters have slender, cormorant-like profiles and long pointed bills adapted for spearing fish. Gannets and boobies also exhibit narrow bodies, long necks, and pointed bills, though their feet are only partially webbed. Some herons share the long neck and harpoon-like bill of cormorants, using them to snatch fish, but have much more spindly bodies and legs compared to the stocky bodies of cormorants.
Bird | Key Similarities to Cormorants |
---|---|
Anhingas | Slender body, long neck, pointed bill, fully webbed feet |
Darters | Slender profile, long pointed bill |
Gannets and Boobies | Long neck, pointed bill, partially webbed feet |
Some Herons | Long neck, harpoon-like bill |
When it comes to coloration, cormorants are predominately dark colored, usually black, brown, or gray. Some other aquatic birds share this dark coloration including the anhinga, double-crested cormorant, and great cormorant. The white-breasted cormorant has a distinctly lighter underside. Birds with similar color patterns include the great blue heron, which has a gray back and lighter front, and some gannets and boobies which exhibit black and white coloration.
Behavior and Habitat
In addition to physical characteristics, the behaviors and habitats of some birds resemble those of cormorants. A foremost behavior is their method of diving from the surface to catch fish and other prey underwater. Cormorants and anhingas are two of the most adept diving birds. When diving, cormorants propel themselves underwater with their feet while pursuing prey. Other diving experts include gannets and boobies that plunge dive from heights, and puffins and murres that also dive propelled by their wings.
Cormorants inhabit coastal areas, lakes, and rivers. They nest in trees and on the ground on islands and shorelines. Birds that occupy similar habitats and nesting sites include herons, egrets, gannets, and some duck species. Cormorants are also colonial nesters, meaning they nest in dense groups for protection from predators. Other colonial waterbirds include gannets, pelicans, and some herons and egrets.
Evolutionary Relationships
Examining the evolutionary relationships between cormorants and other birds can also reveal similarities. Cormorants belong to the order Suliformes which includes gannets, boobies, anhingas and darters. The Suloformes order means “pelican-like” referring to shared traits between cormorants and pelicans. Scientists theorize that all members of this order evolved from a common ancestor. The order Pelecaniformes contains pelicans, herons, egrets, and ibises. While not directly related, Pelecaniformes share some behavioral and physical traits with the cormorant family due to convergent evolution.
Order | Includes |
---|---|
Suliformes | Cormorants, gannets, boobies, anhingas, darters |
Pelecaniformes | Pelicans, herons, egrets, ibises |
Both orders include fish-eating waterbirds with adaptations for diving to catch prey. This suggests convergent evolution as these bird groups evolved analogous traits to succeed in similar aquatic environments, even though they may not share an immediate common ancestor.
Examples of Birds Similar to Cormorants
Now let’s look at some specific examples of birds that are similar to cormorants:
Anhinga
As described earlier, the anhinga is one of the most similar birds to the cormorant anatomically and behaviorally. Like cormorants, it has a long snaky neck and dagger-like bill for spearing fish. Anhingas swim low with just their neck protruding and can dive up to 20 feet underwater propelled by their webbed feet. Two key differences are anhingas have longer tails and much more delicate bodies compared to plump cormorants.
Gannet
Gannets resemble cormorants in their slender shape, pointed bill, and diving behavior. They plunge dive from heights up to 100 feet to catch fish. Their feet are only partially webbed but their streamlined bodies minimize drag. Gannets lack the sinuous neck of cormorants and are colored white with black wingtips.
Pelican
While not directly related, pelicans bear some similarity to cormorants in their ecological niche. Pelicans are also fish-eating waterbirds that plunge dive feet first to catch prey. They have a cormorant-like extendable throat pouch for scooping up fish. Their very large bill and minimal webbing make them less agile divers than cormorants however.
Double-crested Cormorant
This North American species shares the typical cormorant body form. It dives from the surface and pursues fish underwater. During breeding, it grows distinctive yellowish “horns” on each side of its head. Its dark coloration and bright throat patch are also classic cormorant features.
Great Cormorant
The large great cormorant inhabits Europe, Asia, Africa, and Australia. Its big size, dark plumage, lengthy neck, and hooked bill are archetypal of cormorant appearance and physiology. It dives and swims using its webbed feet to chase down fish and crustaceans.
Great Blue Heron
While anatomically very different, the hunting behaviors of great blue herons have similarities to cormorants. These very large herons stand still or walk slowly through water before spearing fish with their sharp bills in a flash. Despite their spindly bodies, they sometimes submerge fully to catch prey like cormorants.
Conclusion
In summary, the birds that are most similar to cormorants share certain anatomical features like a slender, elongated profile, long neck, and pointed bill adapted for catching fish. Aquatic birds with comparable diving behavior include anhingas, gannets and boobies. Evolutionary relatives in the order Suliformes such as gannets and anhingas exhibit especially close similarity. Other waterbirds like herons occupy similar habitats and possess some behavioral likeness but are less closely related. All these birds have evolved adaptations for piscivory, even if distantly related, demonstrating convergent evolution. Unique cormorant characteristics like their short wings, stiff feathering, and totipalmate feet set them apart from all other species. By understanding what traits cormorants share with other aquatic birds, we gain insight into their ecology and evolution.