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Duration: 00:7 minutes Upload Time: 2007-09-23 01:43:52 User: Woodpeckersnest :::: Favorites :::: Top Videos of Day |
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Description: http://www.youtube.com/watch?v=MBruAWoCiv0 Woodpeckers @ home town blues-Woodpeckers also use their beaks to create larger holes for their nests which are 15--45 cm (6--18 inches) below the opening. These nests are lined only with wood chips and hold 2--8 white eggs laid by the females. Because the nests are out of sight, they are not visible to predators and eggs do not need to be camouflaged. Cavities created by woodpeckers are also reused as nests by other birds, such as grackles, starlings, some ducks and owls, and mammals, such as tree squirrels. Several adaptations combine to protect the woodpecker's brain from the substantial pounding that the pecking behavior causes: it has a relatively thick skull with relatively spongy bone to cushion the brain; there is very little cerebrospinal fluid in its small subarachnoid space; the bird contracts mandibular muscles just before impact, thus transmitting the impact past the brain and allowing its whole body to help absorb the shock; and its relatively small brain is less prone to concussion than other animals'. |
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