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
Peter and the Wolf in a pond nearby. The duck starts arguing with a little bird ("What kind of bird are you if you can't fly?" – "What kind of bird are if you can't swim?"). Peter's pet cat stalks them quietly, and the bird—warned by Peter—flies to safety in a tall tree while the duck swims to safety in the middle of the pond. Peter's grandfather scolds him for being outside in the meadow alone ("Suppose a wolf came out of the forest?"), and, when he defies him, saying: "Boys like me are not afraid of wolves", his grandfather takes him back into