Cormorants and anhingas are two types of waterbirds that are often confused with one another due to their similar appearance and behaviors. However, there are some key physical differences between cormorants and anhingas that can help birdwatchers distinguish between the two. In this article, we will go over the main similarities and differences between cormorants and anhingas in terms of their physical characteristics, habitat, diet, and behavior. Knowing the subtle ways in which cormorants and anhingas differ will help you confidently identify which type of bird you are observing in the wild.
Similarities Between Cormorants and Anhingas
Cormorants and anhingas have a number of shared physical traits and behaviors that contribute to the confusion between these two waterbirds. Here are some of the key similarities:
– Both have long, thin necks and long, pointed beaks. This gives them a very snake-like appearance.
– They have short legs that are set far back on their bodies and webbed feet, which are adaptations for swimming and diving.
– Their plumage is predominately black or very dark brown. Some species may have patches of lighter colors on their heads, necks or breasts.
– They have long tails.
– Both cormorants and anhingas spend much of their time swimming low in the water with only their long necks sticking up. When swimming, they propel themselves using only their feet, keeping their wings tucked at their sides.
– They dive underwater to catch fish, often swimming down to considerable depths.
– After fishing, they come up on land or rocks to dry their feathers, holding their wings outstretched.
– They nest in groups, building nests out of sticks in trees or on cliffs.
– They are found along coastlines, rivers, ponds and lakes in many parts of North America.
Due to these shared characteristics relating to anatomy, habitat and behavior, it’s no wonder that anhingas and cormorants can be tricky to tell apart in the field. But with a closer look, some consistent differences do emerge.
Key Physical Differences
While anhingas and cormorants are remarkably similar in their overall appearance, there are some physical differences that can serve as clues for telling the two birds apart:
Size: Anhingas tend to be smaller with more slender, thinner bills while cormorants are larger with thicker bills. On average, cormorants measure about 30 inches long with a wingspan around 48 inches. Anhingas are usually about 26 inches long with a wingspan around 36 inches.
Neck feathers: When dry, cormorants have white neck feathers whereas anhingas usually have dark neck feathers even when dry. The neck feathers of the anhinga have a scale-like appearance.
Tail shape: Cormorants have fan-shaped tails while anhingas have longer, pointed tails. The tail of the anhinga is also thinner.
| Characteristic | Cormorant | Anhinga |
|---|---|---|
| Size | Larger | Smaller |
| Bill shape | Thicker | More slender |
| Neck feathers when dry | White | Dark |
| Tail shape | Fan-shaped | Long, pointed |
These consistent physical differences, though subtle, are very helpful clues when it comes to telling a cormorant apart from an anhinga.
Behavioral Differences
In addition to physical characteristics, cormorants and anhingas exhibit some slightly different behaviors that can aid in identifying them:
Drying posture: After fishing, cormorants often hold their wings outstretched at a 45 degree angle from their bodies to dry. Anhingas more commonly hold their wings horizontally straight out.
Swimming posture: Cormorants swim low in the water with their bodies submerged, whereas anhingas swim with more of their bodies above the water line.
Diving style: Anhingas tend to dive straight down vertically from the water’s surface. Cormorants are more likely to dive in at an angle.
Fishing habitats: While there is overlap, cormorants are more often found fishing in saltwater coastal areas while anhingas prefer sheltered bays, lagoons and freshwater lakes.
Paying attention to these subtle differences in behavior can provide more clues to help distinguish cormorants and anhingas when observing them in the wild.
Range and Habitat
The ranges and habitat preferences of cormorants and anhingas also show some differences:
Range: Cormorants have a wider global distribution than anhingas. Cormorants are found along coastal areas throughout much of North America, Europe, Asia, Africa, Australia, and Antarctica. Anhingas are only native to warmer regions and mainly stick to North America, South America and Africa.
Habitat: While there is some overlap, cormorants are more likely to inhabit coastlines and rocky cliffs while anhingas prefer sheltered bays, lagoons, swamps, inland lakes and rivers further from the ocean.
Migration: In general, anhingas are more likely to be year-round residents in their breeding areas whereas cormorants are more migratory and travel larger distances.
Knowing the preferred range and habitat of each species can provide additional clues if you have a sense of the location and ecosystem where an unknown bird is spotted.
Conclusion
While cormorants and anhingas share many similarities due to their way of life as fishing waterbirds, a trained eye can spot several key differences between the two types of birds. Cormorants tend to be larger in size with thicker bills, white neck feathers when dry, fan-shaped tails, and a preference for coastlines. Anhingas are smaller with more slender bills, dark neck feathers even when dry, pointed tails, and a preference for inland freshwater. minor behavioral differences are also apparent during swimming, diving and drying postures. Being able to distinguish these subtle but consistent differences will set you up for accurately identifying the cormorants and anhingas you come across in the field. With a little practice, you’ll be spotting the difference in no time and adding both these remarkable waterbirds to your life list.
