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
What/If/They Both Could Fly What/If/They Both Could Fly What/If/They Both Could Fly is a live album by Evan Parker and Joe McPhee recorded Norway in 2012 and released on the Norwegian Rune Grammofon label. Allmusic reviewer Thom Jurek states "For fans of improvised music, "What/If/They Both Could Fly" has much to offer. For seasoned listeners, it will not likely reveal many hidden new doors, but it is enjoyable and engaging for its lively interplay, presented in a relaxed, open, and inquisitive fashion". In The Guardian John Fordham wrote "It's a must for free-jazz disciples of Parker and McPhee, but the uninitiated may also find