Bird Watcher's General Store

Parasitic Jaegers
04/25/14


Dear Bird Folks,

A couple of years ago my wife and I were walking near the mouth of the Cape Cod Canal when we saw a strange-looking bird fly in front of us. It turned out to be a Parasitic Jaeger. I'd never seen one before (nor since). The Jaeger was eating a flounder, when a gang of Herring Gulls tried to take it away. The jaeger turned on the gulls, gave them a beating and then went back to feeding. I thought you'd be interested. 

- Ken, Sandwich, MA

Now you tell me, Ken,

Like you, I’ve never seen a Parasitic Jaeger and would have loved to see one. So before I respond to your e-mail, I’d like you to do me favor. The next time you see a strange-looking bird, could you not wait “a couple of years” before telling me about it? I drove down to the canal the minute I read your note, but it seems the bird had already moved on. I’m not sure why it didn’t stay there for two years and wait for me, but it apparently had other things to do. Unlike me, birds have busy schedules.

Parasitic Jaegers aren’t rare birds around Cape Cod, but they aren’t commonly seen from land. Most of the time they are flying just off shore. Jaegers (usually pronounced “yay-ger,” sometimes “jay-ger” and very rarely, Jaguar XKE) are fast flying gull-like seabirds that spend much of their time out in the open ocean. The name jaeger comes from a German word meaning “hunter,” which is appropriate because jaegers are excellent hunters. But the part of the name that really fits this bird is “parasitic.” When jaegers aren’t in the mood to hunt, they will simply steal food from other seabirds. By using superior flying skills and a pugnacious attitude, a jaeger will harass a gull or a tern until it coughs up a recently caught fish…or hands over its lunch money. Jaegers are considered to be the bullies of the sea, but unlike other bullies, jaegers can back up their blustering. Often punching well above their weight class, jaegers will steal food from birds that are three times heavier. Here’s your word of the day: When one bird steals from another, it’s called “kleptoparasitism.” (Try using that the next time you play Words With Friends and you’ll have enough points for the rest of your life.)

It should be noted that Parasitic Jaegers are most often food thieves during the winter. In the summer, when they are on their high Arctic breeding grounds, jaegers stop being crooks and take things up a notch. There they become killers. Like I said earlier, jaegers are excellent hunters and they have no trouble catching their own food when the mood strikes them. As much as I hate to say it, jaegers are really good at catching and eating other birds, including songbirds. With their superior flying skills, jaegers have little trouble overcoming most birds. And if that wasn’t bad enough, mated pairs of Parasitic Jaegers are one of the few bird couples that will hunt as a team. One jaeger will fly below the target bird, to keep it from going for protective cover, while its partner attacks from above. Parasitic Jaegers are truly the ultimate power couple.

While jaegers can’t capture big birds, it doesn’t mean these larger birds are safe from the jaegers’ wrath. When jaegers spot, say, nesting loons, they dive at the parents in an effort to drive them off their nest. If the jaegers succeed, they quickly move in and help themselves to fresh loon omelets. In addition to birds, Jaegers will also eat small mammals, insects and even berries, just to prove they are equal opportunity predators.

Because Parasitic Jaegers breed in the Arctic and spend the winter out at sea, casual birders aren’t likely to see them (unless they are fortunate enough to stumble into one eating a flounder at the canal). But with a little effort and some luck anyone can see one of these feisty birds. Sometimes strong storms push these seabirds close to shore. But who wants to stand out in the middle of a storm? The better, safer and drier way to see Parasitic Jaegers is to look for terns. At the end of each summer, when many folks are closing down their second homes and cottages, thousands of terns are also getting ready to head out for the season. Before they go, terns form large flocks along Race Point in Provincetown or on South Beach in Chatham. This pre-migration gathering is called “staging” and is different than the gathering of departing cars we find at the Sagamore Bridge. The clouds of swirling terns not only catch the attention of human observers, they are also magnets for the jaegers that have just arrived from the North. Tired of hunting for their own food, the jaegers have decided that it’s the terns’ turn to do their hunting for them. When a tern catches a fish, a jaeger or two, will lock onto it like a Minuteman missile. The Jaegers won’t stop harassing the tern until it coughs up the goods. I know it doesn’t sound fair, but in the end the joke is on the jaegers. They end up eating fish covered in tern spit. Ha, ha!

Parasitic Jaegers, with their brazen aerial acrobatics are remarkable birds to see in action, Ken. You were very fortunate to get such a good look at one. However, some folks don’t like jaegers. They feel bad for the terns that are constantly getting their hard-earned fish stolen from them. To which I reply: Really? You feel bad for the terns? If you are going to feel bad for anything, feel bad for the fish. There is never a happy ending for the fish. See, even I can be philosophical.




Artwork by Catherine Clark


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