thermoregulationJune 19, 2006
I had this idea that I'd take a Monday off from Gray Cubicle World (not its real name) to do a plover warden shift on a weekday for variety and in hopes of feeling more connected to what's happening on the refuge. Mainly what I'm feeling is hot. It's hot and humid. Really really hot and humid. On the other hand, it does feel good not being in a gray cubicle on a Monday morning.The first bird I saw was an osprey cruising over the ocean. You don't see those in gray cubicles at the nexus of 128 and Rt. 3! The opsrey came back a few times but I didn't see it catch any fish.
Unsually for this season, I'm at the north boundary this morning. I've almost always been south this year. I missed a couple of shifts due to rain and I think one of those I would have been north -- I don't have the schedule in front of me. Despite the myth that north is busier than south visitor-wise I always seemed to get about the same number of people to talk to at both ends. The major difference between north and south for me is that the north means dogs and the south means kayakers. Both listen about as well. :-)
There was a steady stream of visitors but not as overwhelming a number as I thought there'd be on such a hot day. I had it easy compared to refuge biological staff and their helpers who were putting up electric fencing around the least tern colony. I can't imagine sweltering in the humid haze AND being pooped on by defensive least terns at the same time.
Other than the osprey flybys and a couple of terns there's not much bird action on the beach. A little ways down the beach, there's a ringbilled gull with its mouth wide open and its throat vibrating. Soon it was joined by a common grackle who also faced south with beak wide open like it was panting. The grackle flew about 5 feet further south, landed, and started panting again. All the gulls on the beach, as well as the grackle, are facing the same way.
At first I thought the ringbill was doing some new kind of flycatching technique because it did seem to grab a couple of flies while it was sitting there, but it slowly dawned on me that it was more like a dog panting. I guess gulls (and grackles) don't sweat. I never thought about how gulls keep cool.
Back home I consult my Birdwatcher's Companion under Thermoregulation, where it tells me to see Temperature, body. Aha! I guessed right -- birds don't have sweat glands. They can make use of evaporative cooling, though, by vaporizing water in the lungs and internal air sacs and then releasing it by panting. The throat vibration thing is also a cooling mechanism called "gular flutter." They release internal heat by quivering the skin of their throats and increasing the blood flow.
Further reading on the Internet (whatever did curious people do before Google?) tells me that the direction they're all facing is a cooling adaptation too. Apparently gulls will rotate to always face the sun on hot days. Supposedly this reduces heat gain by minimizing the sun-exposed surface area and by orienting the white parts, the most reflective, to direct sunlight to minimize how much heat they gain from the sun. I didn't find anything on why grackles, who are all dark, would orient themselves that way.
Plum Island
least
tern 3
common tern 2
osprey 1
great black back gull 2
herring gul 3
ringbilled gull 1
double crested cormorant 1
common grackle 1
tree swallow 1
Today's Reading
The Honorable Visitors by Donald Richie, Field Notes: The Grace Note of the Canyon Wren by Barry Lopez, Birdwatcher's Companion by Christopher Leahy
2006 Booklist
Ignore this thing below if you are reading the Plover Warden Diaries.
|
|
||
Copyright © 2006, Janet I. Egan