Bird migration evidence. Seabirds fly low over water but gain altitude when crossing land, and the reverse pattern is seen in landbirds. However most bird migration is in the range of . Bird strike aviation records from the United States show most collisions occur below and almost none above . Bird migration is not limited to birds that can fly. Most species of penguin (Spheniscidae) migrate by swimming. These routes can cover over . Dusky grouse "Dendragapus obscurus" perform altitudinal migration mostly by walking. Emus "Dromaius novaehollandiae" in Australia have been observed to undertake long-distance movements on foot during droughts. While participating
Oozlum bird rips from the sky. The oozlefinch has been adopted as the unofficial mascot of the United States Air Defense Artillery. The oozlum bird was the subject of the British 1970 film, "Carry On Up the Jungle". There was also a recurring joke in an episode of the BBC radio comedy, "The Navy Lark" that Lt Commander Murray (Stephen Murray) did not know what the oozlum bird was. Sub Lieutenant Phillips (Leslie Phillips) suggested that when young, oozlum birds fly straight, and it is only when they turn left that the trouble starts. The oozlum bird is sometimes used as a