We know that squirrels
make the most of fall's plenty by hoarding nuts for the winter, but the fact
that birds also store, or cache, food goes largely unappreciated. Through
clever observation and experiments, biologists have found that food caching
(from the French cacher, "to hide") has developed to a high art in
some birds.
Take the chickadee, for
instance. Chickadees put tens of thousands of food items a year into short-term
storage. They usually retrieve and eat the food in the space of several days. Each
food item is cached in a different place to make it difficult for thieves to
steal all the food at once. When hiding a new item, they remember their
previous storage sites and avoid placing caches too close together. Chickadees
remember each hiding place for around a month, even though they may be
scattered widely across a bird's territory. Research shows they use visual cues
to navigate back to each of their cache sites by a combination of larger
landscape features, particularly verticals, and use of the sun as compass.
Smaller local details are not as critical, probably because these often change
in a forest. When retrieving food, they remember which sites have been emptied,
either by them or by robbers, to avoid fruitless searching.
How does a tiny bird
have such brain power?
No comments:
Post a Comment