Laura Erickson's For the Birds

In a country inhabited by well over 250 million people on a planet with over 5 and a half billion people, it gets harder and harder to do anything unique. But I think I managed to accomplish a genuinely unique feat this summer when I drove down to the Twin Cities with Annie and Snarfy the nighthawks, and radiographed their innards. Somehow I suspect that even with the world population at this extraordinary level, it would be hard to find anyone else who finds nighthawk guts all that interesting.

But Gary Duke, a founder of the Raptor Center and one of the world’s leading authorities on bird digestion, is a gutsy kind of guy, so we set out to get the inside story on nighthawk digestion. I fed the birds a plop of food laced with barium, put them in a little two-story box, and Gary turned on the veterinary school’s radiograph machine.

Annie, the young and the restless, waddled about a bit, so we could observe her from side to side–a funny, animated little skeleton. Snarfy found the procedure utterly boring, and yawned several times.

Nighthawks have an enormous stomach–it fills about a quarter of their internal cavity. Their intestines are small and short, with a pair of little offshoots called caeca at the juncture between the small and large intestines where our appendix would be. Nobody knows for sure why nighthawks have caeca. They may help the bird regulate its body fluids, or they may harbor bacteria that secrete an enzyme that digests the chitin in the exoskeletons of beetles and other hard insects. Owls also have caeca, though hawks do not. Scientists guess that owls originated as insect eaters while hawks originated as bird and mammal eaters. The whole point of my Ph.D. research will be to figure out the function of these odd structures that make nighthawk droppings smellier and yuckier than most bird droppings.

I thought the interesting part of watching nighthawk digestion would happen when the food finally made it down to the caeca, but it turns out that the nighthawk duodenum is equally fascinating. There is a thick section right where the stomach empties in, and when the food reached this part, it sloshed back and forth for many minutes. Gary, who has radiographed a wide variety of birds, from hawks to ostriches, had never seen this duodenal slosh before. Now we’re guessing that perhaps the caeca really are for regulating fluids, and that the duodenum is where the real digestion takes place.

It may take years to unravel this mystery, especially because no way am I going to sacrifice a single bird for the research. This one time radiographing is the most invasive procedure I’ll ever do. But little by little, I’m working toward finally earning the title “The Bird Gut Queen.”

Here is what I must have aired a few years later, but don’t know the date.

In a country inhabited by over 260 million people on a planet with 6 billion people, it gets harder and harder to do anything unique. But I think I managed to accomplish a genuinely unique feat a few summers ago when I drove down to the Twin Cities with two nighthawks named Annie and Snarfy, and radiographed their innards. Somehow I suspect that even with the world population at this extraordinary level, it would be hard to find anyone else who finds nighthawk guts all that interesting.

But Gary Duke, a founder of the Raptor Center and one of the world’s leading authorities on bird digestion, is a gutsy kind of guy, so he and I set out to get the inside story on nighthawk digestion. I fed the birds a plop of food laced with barium, put them in a little two-story box, and Gary turned on the veterinary school’s radiograph machine.

Annie, the young and the restless, waddled about a bit, so we could observe her from side to side–a funny, animated little skeleton. Snarfy found the procedure utterly boring, and yawned several times. The two of them reminded me of cartoons where the character gets into the x-ray booth. Fortunately, the university radiograph equipment is state-of-the-art stuff with very low levels of radiation.

Nighthawks have an enormous stomach–it fills about a quarter of their internal cavity. Their intestines are small and short, with a pair of little offshoots called caeca at the juncture between the small and large intestines where our appendix would be. Nobody knows for sure why nighthawks have caeca. They may help the bird regulate its body fluids, or they may harbor bacteria that secrete an enzyme that digests the chitin in the exoskeletons of beetles and other hard insects. Owls also have caeca, though hawks do not. Scientists guess that owls originated as insect eaters while hawks originated as bird and mammal eaters. The whole point of my on-again, off-again Ph.D. research is to figure out the function of these odd structures that make nighthawk droppings smellier and yuckier than most bird droppings.

I thought the interesting part of watching nighthawk digestion would happen when the food finally made it down to the caeca, but it turns out that the nighthawk duodenum is equally fascinating. There is a thick section right where the stomach empties in, and when the food reached this part, it sloshed back and forth for many minutes. Gary, who has radiographed a wide variety of birds, from hawks to ostriches, had never seen this duodenal slosh before. Now we’re guessing that perhaps the caeca really are for regulating fluids, and that the duodenum is where the real digestion takes place.

It may take years to unravel this mystery, especially because no way am I going to sacrifice a single bird for the research. This one time radiographing is the most invasive procedure I’ll ever do. But little by little, I’m working toward finally earning the title “The Bird Gut Queen.”