Show Migrating Birds According to the bureau of bio bio- biological biological biological logical survey few migrating birds fly higher than feet and only occasionally do they reach feet Most birds like to fly beneath the clouds and the ma ma- majority majority majority of the species migrate at a height below 1000 feet In bad weather they may fly much lower as evidenced by the number that strike against lighthouses and high buildings Birds have of course been seen at much higher alti alti- altitudes altitudes altitudes tudes but these records were es es- established established es- es established in mountainous countries where the birds fly a comparative comparative- comparatively ly short distance above the land The bureau explains that migrating migrating migrating ing birds fly at low rather than high altitudes by the fact that the lessened buoyancy y of air at great heights makes flying difficult |