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
Not Only... But Also parody of "Thunderbirds" and other Sylvia and Gerry Anderson puppet shows), and the "rhythmic voodoo" R&B singer Bo Dudley – though the fame of these almost certainly owes much to the fact they still exist in vision, unlike much of the series. Contrary to popular myth, the Cook perennial "One Leg Too Few", a classic sketch about a one-legged actor applying for the role of Tarzan, which had been written by Cook when he was 18 years old and used in "Beyond the Fringe", never appeared on the BBC "Not Only... But Also", although it did feature in one of