A Little Bit More
There’s a good chance you’ve never really thought about how a bird can incubate its eggs when its feathers are such good insulators – now you know! Although the unit poster notes that birds lose their breast feathers at the time of incubation, ducks and geese are a bit different - they pull their own feathers out instead and use them to line their nests.
Downy Woodpecker with brood patch
If you’re able to inspect an incubating bird that’s in your hand, you’ll see that its bare skin is quite flushed with blood. There is a supplemental blood supply that kicks in during incubation to insure that the eggs can be brought to a temperature that permits the embryo to develop normally. For most birds, like hawks, pigeons, grebes, and songbirds, there is only a single brood patch. But the shorebirds have two and gulls, and chicken-like birds have 3. The pelicans have no brood patch at all but instead warm their eggs with both body and feet during incubation. As you might expect, only the sex(es) that incubates has a brood patch – if males incubate they too have this ability.
Activities
Science – Temperature Please
Objectives: Understand that human bodies have “hot spots” too
Materials: Thermometer (small one that can be placed against body)
During the 1980s, the International Crane Foundation, located in Baraboo, Wisconsin, was breeding rare and endangered cranes. The Foundation received permission from Russia to gather a few eggs from the rare Siberian Crane in Siberia to raise in Wisconsin. All went well until the carrier was ready to board her plane in Moscow with the eggs. The airline didn’t want the egg container to accompany the carrier in coach. The eggs had already begun incubation in the wild so they needed to remain warm in a specially built box with a hot water bottle for the trip. There was a stalemate with the airline saying the box couldn’t stay in the passenger area and the carrier insisting the box had to accompany her. At last, the carrier, a rather tiny, spunky woman, said she’d take the eggs out of the box and put them in her blouse if they didn’t permit the box to accompany her. That did it…the airline relented and the box accompanied her all the way home.
Although this is an interesting and true story, the eggs really wouldn’t have remained warm enough on her body; she knew that, but the airline didn’t. The eggs would have been warmer on her body than if they had been left in the box without frequent hot water bottle changes, however.
The “Bare Midriff” poster focuses on the extra warmth that needs to be generated by an incubating bird. Humans also have warmer areas on our bodies too although this has nothing to do with incubation, of course. I think it would be interesting to take the temperature of various areas on a person to see just how much difference there can be from one body area to another. Most of us have had our temperatures taken orally but it’s also possible to use other body areas too. We’ll focus on a few “acceptable” body locations to get a ballpark idea of temperature differences.
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1. Select a student subject who is willing to have “their temperature taken” Be sure to place the thermometer on the skin - under any clothing is fine
2. Take their temperature (wait at least 5-6 minutes for any change to be registered) at several locations – (suggested areas include: armpit, forearm, forehead, ankle, stomach, back of neck)
3. Be sure to note these locations and temperatures on paper/blackboard so you can refer to them later
It should be apparent to all that our bodies have warm and not-so-warm areas – we’re not a consistent temperature all over. Although the average normal human core body temperature is 37°C (98.6°F), it’s doubtful you’ll even come close to this temperature with the locations we’ve chosen.
Key Concepts
Structures and Functions, Reproduction, Life Cycles, Behavior and Regulation
Questions
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