For the Birds Radio Program: Sneakers vs. Fred through a Stethoscope
Ever listen to a bird’s heart through a stethoscope? Laura Erickson has. (3:40) (Date confirmed)
Last week I taught a bird class for some sixth and seventh grade girls. We spent part of the time outdoors studying bird identification, but most of the time we were indoors studying bird anatomy and physiology. We used my licensed education birds, Sneakers the Blue Jay and Fred the Nighthawk, as our prime exhibits. Fred graciously goes along with just about anything. He held perfectly still on the balance pan while we weighed him, and if he found the procedure boring, he was to polite to say so. Sneakers was a different story. There is just no way you can make a Blue Jay sit still on a balance pan, so we ended up putting her in a cardboard box and figuring out the difference. We discovered that Fred weighs just over 80 grams, and Sneakers 96 grams.
Then we got a stethoscope to find out what their heart rates are. Fred is so laid back and slow and Sneakers so excitable and active that we hypothesized that Sneakers’s heart would greatly outpace Fred’s. A healthy bird’s pectoral muscles and keel bone are too thick to hear through, but you can hear the heart just fine listening through the back. Fred cooperatively allowed us to feel around with the instrument and let each girl listen in. A nighthawk’s heart rate is too fast to count the individual beats, but with a sense of rhythm we can hear quick measures of four beats and so we simply counted the measures, calculating his heart rate at 336 beats per minute.
Sneakers found the stethoscope right interesting as long as we held it on Fred, but she was livid when we tried it on her, so I had to hold her tight. It was hard to hear anything over all her squawking, but from what we could hear, her heart didn’t sound much faster than Fred’s. So we looked up bird heart rates in a reference book. There wasn’t anything listed for the nighthawk, but it did show the Blue Jay’s heart rate as 307 beats per minute–actually slower than Fred’s 336. So our hypothesis was proved wrong. Apparently, the size of a bird is more important thank its activity level in determining how fast its heart pumps.
During the course of the week, the girls were mightily impressed with both birds. Blue Jays and nighthawks have diametric personalities—when the girls recorded behavior during the week, they couldn’t keep up with Sneakers’s busyness, hopping from one perch to another, bathing, eating, pecking her perch, looking for peanuts under the newspaper, looking out the window, trying to catch a fly—she went from one activity to another much faster than they could write it all down. Fred mainly sits. They had time to write down each type of feather he preened, and spent most of their time yawning as he looked at them with gentle but serious eyes. I thought Sneakers would be the favorite for her colorful beauty and jolly ways, but it turns out the girls like them equally: Fred for his dignified manners and Sneakers for her spunky personality.
That’s the best thing about birds. Each species is uniquely wonderful. The girls learned a lot more about the heart than you’d think by setting a stethoscope on a couple of birds.