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Show Migrating Birds ? According to the bureau of bio- I logical survey, few migrating ' birds fly higher than 3,000 feet and ' only occasionally do they reach 5,000 feet. Most birds like to fly I beneath the clouds, and the ma- jority of the species migrate at a "v height below 1,000 feet. In bad I weather they may fly much lower as evidenced by the number that ' strike against lighthouses ani high buildings. Birds have, of course ' been seen at much higher alti- tudes, but these records were established es-tablished in mountainous countries ' I where the birds fly a comparative- ) ly short distance above the land. The bureau explains that migrating migrat-ing birds fly at low rather than high altitudes by the fact that the j lessened buoyancy of air at great heights makes flying difficult. I |