provided by Clinic for the Rehabilitation of Wildlife
When scouting for water birds and shorebirds, it is common to encounter a large, black bird perched on the water’s edge, or a lightpost, with its wings outstretched absorbing the sun’s rays. Often times it is a double-crested cormorant; the most generally distributed cormorant in North America. Sometimes, one will be lucky enough to spot an anhinga. Although slightly similar in appearance, the two have several distinguishable differences that properly identify them in the wild.
The word Anhinga originates from the Brazilian Tupi language. Anhingas are found in shallow, slow-moving, sheltered waters and are commonly referred to as snakebirds, darters, or water turkeys. They have long, s-shaped necks with straight, daggerlike bills. The eighth and ninth cervical vertebrae create a hinge apparatus that allows the quick, striking motion in catching prey. Anhingas have longer tails than double-crested cormorants that fan out to look like a turkey tail in flight. Adult males are almost entirely black with silvery, white streaks on their back and wings. Female anhingas and immature individuals present with a pale head, neck, and breast with a sharply contrasted dark belly.
Deceptive in their appearance, looking more like a cross between a goose and a loon, the double-crested cormorant is surprisingly a relative of frigatebirds and boobies. The double crest is only visible on adults during breeding season which is black in most regions other than in Alaska where the double crest presents as white. Found in almost any aquatic habitat, they are incredibly adaptive birds. They have a curved bill with a sharp hook at the end, not as long or pointed as the anhinga. They are dark in color overall with shorter necks and tails than the anhinga. Juveniles have a pale neck and breast that gradually blends into a darker belly. Double-crested cormorants are brightly colored in some strange places. Around the base of the bill and chin, the skin has an orange and yellow vibrance. Their eyes are aquamarine and the inside of their mouths are electric blue.
Both the anhinga and double-crested cormorant exhibit similar behavior after hunting and foraging in the water. Spreading their wings and sunning is a behavior developed to dry their feathers after swimming in preparation for flight. Both the anhinga and cormorant have a lack of waterproof feathers with less preen oil than other birds which means their feathers are easily soaked. This seems like it would be problematic, but this ability to take on water makes it easier for them to hunt underwater effectively. Though, their buouancy in the water slightly differs. The anhinga swims low in the water with its body partly or mostly submerged with only the neck or bill visible, displaying that the term “snakebird” is rather appropriate. Anhingas are not fast swimmers and prefer to slowly stalk their prey. When hunting they may wait for fish to approach and then impale it with a lightning-fast strike. Double-crested cormorants are powerful swimmers that dive into the surface of the water and propel themselves deeper using their feet and wings to catch faster-swimming fish.
At CROW, double-crested cormorants are admitted far more frequently than anhingas. On January 18, a juvenile anhinga was admitted from Sanibel after being found moving slowly. Upon closer inspection, it was obvious there was a string wrapped around the middle of the patient’s beak. The patient’s body composition was thin, but not emaciated. The string was untangled from its beak and the patient was given fluid therapies to rehydrate and provide caloric nutrients. In addition to the beak entanglement, it was later noted that the patient had symptoms of red tide poisoning. The patient is being closely monitored and given fluids to help with the detoxification process.
One final way to undeniably tell whether a bird is an anhinga or a double-crested cormorant is to look at their flight. Anhingas are able to soar and require gliding flights from trees to start off, then continue on using a flap and glide method. Double-crested cormorants are unable to soar but can easily take off from the water and once in flight they continually flap with no glide.
THIS WEEK AT CROW (1/13-1/20):
There were 90 new patients admitted to CROW’s Wildlife Hospital including 20 northern raccoons, three royal terns, two gopher tortoises, two brown pelicans, a chicken turtle, a red-shouldered hawk, and a brown thrasher. Recent Releases include a bobcat, a yellow-rumped warbler, a boat-tailed grackle, and a black scoter. Check out a full list of CROW’s current patients and recent releases!
Wildlife doesn’t have health insurance! Your donations help cover the costs of medical and rehabilitative care for over 5,000 patients admitted to CROW’s Wildlife Hospital each year!
Want to learn more about wildlife rehabilitation? Stop by CROW’s Visitor Education Center at 3883 Sanibel Captiva Road.
About Clinic for the Rehabilitation of Wildlife (CROW)
Established in 1968, the Clinic for the Rehabilitation of Wildlife (CROW) is a teaching hospital saving the sick, injured and orphaned native and migratory wildlife of Southwest Florida and beyond. Through state-of-the-art veterinary care, public education programs and an engaging visitor center, CROW works to improve the health of the environment, humans and our animals through wildlife medicine. For more information, or to plan your visit, go to http://www.crowclinic.org. If you find an animal that is in need of help, call (239) 472-3644 ext. #222.