Most of us who live here are familiar with a phrase used by tour guides to describe our island's uniqueness: "we have fish that fly, birds that swim." For an animal to do the unexpected (from a human perspective) makes it a novelty. This week's article will deal with one of those novelties, the diving bird known as the cormorant.
Cormorants are relatively large, dark colored birds with long, slender necks and thin bills. Adults have bills with a curved tip and often colorful faces and throat regions. Some develop feathery crests on their head during breeding season. Groups of cormorants may fly in V-shaped formations like geese, but they do not make any noise in flight.
There are actually several different species of cormorants in our area including the double-crested, Brandt's and pelagic cormorant. These birds can be observed all along our coast either resting on rocks, swimming or diving in the water. Those observed on rocks often have their wings spread out to dry in the sun.
Cormorants tend to nest in colonies, usually on rocky areas along the coast. The nests are made of seaweed, feathers, sticks, twigs and/or grasses. The double-crested cormorant can be found on inland lakes and often uses trees to nest in there. Most species found here lay 3-6 bluish eggs in the nest. When nesting, these birds may make various noises with different species using different sounds. If different species nest in the same area, they usually choose different types of nesting areas such as cliff tops, ledges or shallow slopes.
Cormorants eat fish and crustaceans. They may dive to significant depths in search of food. Brandt's cormorant often fish together, diving as a group to form a "living net" forcing fish to gather together making them easier prey. Most of the pictures accompanying this article were taken in the Dive Park. A cormorant suddenly appeared in front of me at 65 feet, on its way to the surface. The visibility was very good so I was able to watch the cormorant at the surface. When I saw it begin its dive, I started my video camera and captured it as it swam down to my depth. It reached the bottom just in front of me so I was able to follow it with the camera as it searched for food. Instead of capturing the many blacksmith fish that were swimming in the area, it kept poking its head under rocks. It may have been searching for crabs or other crustaceans, or possibly young blacksmith hiding there.
Japanese fishermen have used the practice of Ukai, or cormorant fishing, for 1,300 years. Trained cormorants are fitted with leashes and metal rings around their necks to prevent them from swallowing the fish. They are released into the water to capture fish which the fisherman makes them disgorge from their throat pouch at the surface. In return they are rewarded with some food. At one time this practice was used to provide freshwater "sweetfish" to the Japanese Imperial family. Today very few fishermen are allowed to practice Ukai, and permits are usually passed on within the selected families who use it mainly to present Japan's cultural history to visitors.
These diving birds and our summer visitors, the flying fish, sure make me envious. Many times when the Dive Park stairs are packed with SCUBA classes entering the water, I've wished my SCUBA gear had a rocket pack that I could use to fly quickly to the location I wanted to dive. Of course wishing for a bit more patience would be an easier request to fulfill.
© 2003 Dr. Bill Bushing. Watch the "Dive Dry with Dr. Bill" underwater videos on Catalina Cable TV channel 49, 10:00 AM and 5:00 PM weekdays.
Image caption: Cormorant on shore; diving to 65
looking for food at 65 feet; returning to surface from shallow dive
This document maintained by
Dr. Bill Bushing.
Material © 2003 Star Thrower Educational Multimedia