A Little Bit More
Anyone who has watched birds for even a short length of time soon realizes that they spend a lot of time preening. On the surface it may appear that it isn’t much more than a rearranging of feathers but as the unit poster notes, distributing oil is also an important activity for a healthy bird. The preening activity distributes oil from the preen gland over the feathers but also functions to position the feathers a bit like the shingles on a roof. A bird’s feathers are arranged so they neatly overlap one another, and are able to prevent both water and air from reaching the skin where they can “rob” the animal of heat. This means a bird is both buoyant and insulated from the cold, whether it be in water or air.
When a bird preens and places its own oil on its body this is helpful, if not crucial, but there are times when the wrong kind of oil can have catastrophic effects on birds and other water creatures. Birds that get into oil spills, wherever these may occur, are at real peril because instead of providing insulation, petroleum products end up causing a bird’s feathers to mat and this eliminates their ability to insulate the bird’s body. During an oil spill, many birds die from exposure to the elements from an “over-dose” of oil that they’ve gotten on their bodies simply by swimming through the material.
Definitions
castastrophic: overwhelming, tragic event
Activities
Science – Water off a duck’s back
Objectives: See how effective oil can be for waterproofing
Materials: Newspaper, stick of butter or margarine, water, spoon
This is a very simple exercise but one that clearly demonstrates the effectiveness of oil on a given substance. We won’t use feathers but we’ll use paper instead to make our point.
- Cut two similar pieces of paper from a newspaper approximately 4”X 4”
- Use a stick of butter or margarine (works best if cold from the refrigerator) to coat one side of only ONE paper square – leave the other square clean
- Using a spoon (or eyedropper) drop a few drops of water onto the newspaper that was NOT oiled
- Using the same amount of water, drop a few drops onto the newspaper that was oiled
- Observe the difference, if any. This may take a few minutes
It should be obvious to students what the difference is between the two pieces of paper after a short time. From this demonstration, they can better understand how oiled feathers are more water resistant than non-oiled ones.
Key Concepts
Structures and Functions, Behavior and Regulation, Adaptations and Diversity
Questions
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