Dive Dry with Dr. Bill

#223: Cormorants: Birds That Swim, Fish That Fly

I've never been very good at identifying birds, even in the days of my youth when I used to roam the fields and streams of suburban Chicago. There's just something about them that never really appealed to me. The only bird I'm very serious about is the turkey served for lunch on the King Neptune... although I may have to switch back to soy turkey if everything goes well (remember the great soy turkey sandwiches from Alma's Health Food Bar in the 1970's?) . Perhaps it is because birds fly way "above my head" (and occasionally drop little "gifts" on it) instead of at my eye level under the sea. Or maybe it is because I've met too many amateur birders who seem obsessed with keeping life lists of the birds they have seen, and are preoccupied with rarity to an extreme. I find life lists to be symptomatic of the collector mentality, possibly indicating some strange psychological disorder... and I've always felt that the common species are the key to understanding how an ecosystem really works, not the rare ones. I have no idea how many species I've seen underwater, and what difference would it make anyway? I'm glad there are millions of them I have yet to see!

Our local Catalina tour guides often refer to the list of oddities about our Island when they spiel to our visitors. You know... "we have a Casino in which there is no gambling, a Third Street but not a First or Second, Vons grocery store delivers (do they?) but the Post Office does not." Another phrase in this mantra is "We have fish that fly, and birds that swim." I've already written about Catalina's famous flying fish in a previous column, but it has been four years since I've written about our diving birds, the cormorants. Time to revisit this interesting group!

Cormorants are fairly large, dark (in color, not mood) birds with long necks and slender bills that have a hook at the end. My limited ability to actually identify these to the species level is a matter of intellectual laziness, since there are only three species here in our waters, and 37 world-wide. Ours include the double-crested, Brandt's and pelagic cormorants. The double-crested has a yellow pouch at the base of its bill, while the Brandt's has a blue pouch with a buff patch nearby, and the pelagic has a dull red face. Perhaps I have trouble identifying them because I'm partially color-blind.

Cormorants contribute to the snowy white coating on many of our coastal rocks along with their seagull and pelican "fellow travelers." They've made their contribution to the only downhill slope on Catalina, you know... "Ski Bird Rock." While resting on these rocks, the cormorant will often spread its wings wide so they dry out in the sun. Unlike the noisy gulls, these birds are generally silent and only issue low grunts when gathered together. Sounds something like what I heard coming out of the Marlin Club last weekend. When they fly in groups, they usually do so in V-shaped formations or straight lines.

The sexes in cormorants are difficult to tell apart on casual observation (and I'm not about to get any more intimate with them!). During breeding season they may have different plumage or patches on their bodies, or a crest may develop on their heads. These birds tend to nest in colonies. When they coexist in a region, the different species usually choose different areas to nest. Cormorants create their nests out of seaweed, sticks and/or grasses on coastal islands or cliff faces. All three species lay between three and six pale blue eggs.

When feeding, these diving birds may descend to depths up to 150-200 feet, although I have yet to see one in our waters below 100. They pop below the surface in a forward dive, then swim with their wings held close to the side. Propulsion is accomplished using the feet with long glides often following the kicks. Cormorants can cover quite a bit of territory underwater during a dive. They often feed on schooling fish like blacksmith, but may even hunt for them in the rocks, but will also feed on crustaceans and other invertebrates.

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 human 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. Perhaps I should try training a few of them myself given my "skills" as a fisher!

Several years ago I was filming in the dive park at a depth of 65 feet. A cormorant "flew" up right in front of me on its way towards the surface. The visibility was excellent so I was able to watch it as it bobbed up there. As soon as it dove, I followed it with my video camera as it came down in front of me and searched under the rocks for a snack. I was able to capture the entire dive, which lasted just over 30 seconds, in one take. Over the past few weeks I've been diving the park and had a number of "close encounters" (of the best kind) with diving cormorants. One surfaced just in front of me, literally swimming up the front of my wetsuit! Fortunately my quick wits allowed me to capture it as it rose to grab a gulp of air. It then dove down close to me and hunted among the rocks of the breakwater as I filmed. I was amazed to find that it would enter one hole in the breakwater, swim through the caverns there and exit out another hole 30-40 feet away. More recently my mind has focused on a "bird" of a different feather. Someday I may tell my readers about that encounter!

© 2007 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. Please help me climb out of self-imposed poverty... buy my "Munching and Mating in the Macrocystis," "Great White Sharks of Guadalupe," "Calimari Concupiscence: Mating Squid, " "Playful Pinnipeds: California Sea Lions," "Belize It or Not: Western Caribbean Invertebrates, Fish and Turtles" or "Gentle Giants: Giant Sea Bass" DVD's. Yes, take Dr. Bill home with you... we'll both be glad you did!

Cormorant surfacing in front of me... and diving back down;
cormorant hunting for blacksmith or crustaceans underwater

This document maintained by Dr. Bill Bushing.
Material and images © 2006 Star Thrower Educational Multimedia