Mackenzie Valley route, 60 Magnetic sense, 30 Magnus, Olaus, 4 Mallard, 22, 31, 33, 58 Man-o'-war bird, 30 Martin, purple, 12 Migration, advantages of, 6 altitudes, 26 distances, 38 diurnal, 15 fall, 37 historical accounts, 4 long distance, 38 mystery of, 4 nocturnal, 15 origin, 7 perils, 75 problems, 81 routes, 41 segregation during, 31 short, 34 species and groups, 12 speed, 18 theories of causes, 7 undetermined, 34 vagrant, 73 variable, 35 vertical, 72 weather, 80 Mississippi Valley route, 60 Mockingbird, 83 Movements of residents, 82 Movements of species and groups, 12 Murre, 29 Mystery of migration, 4 Nighthawk, 9, 16, 32, 38, 55, 60, 70 Nocturnal migration, 15 Northern ancestral home theory, 8 Nutcracker, Clark's, 73 Nuthatch, 7 white-breasted, 83 Orientation, 28 Origin of migration, 7 Oriole, 15 orchard, 9 Ovenbird, 70, 78, 80 Owl, great horned, 34 screech, 83 snowy, 12, 74 Pacific coast route, 63 Pacific oceanic route, 66 Passerella iliaca, 35 Pelican, 4, 16, 26 Perils, aerial obstructions, 76 exhaustion, 78 migration, 75 storms, 75 Pewee, western wood, 72 Phalarope, 33 northern, 27 Photoperiodism, theory of, 9 Pigeon, homing, 30, 31 Pintail, 22, 55, 62, 79 Pipit, 73 Pliny, 4 Plover, 15 golden, 11, 19, 48, 49, 51, 54 (map), 66, 68, 71, 79 upland, 15 Poor-will, 5 Problems, migration, 81 banding studies, 81 migration of the white-throated sparrow, 84 migration of the yellow-billed loon, 84 movements of residents, 82 Quail, 2, 34 California, 82 migratory, 2 Rail, 4, 15 Carolina, 79 Raven, 19 Redhead, 58, 62, 85 Redpoll, 12 Redstart, 14, 45, 47 (map), 70, 78 Residents, movements of, 82 Robin, 9, 22, 24, 33, 34, 35, 61, 70, 76 Routes, 41, 53 (map) Arctic, 68 Atlantic coast, 53 Atlantic oceanic, 48 "bobolink," 55, 56 (map) evolution of, 70 flyways, 46 Great Lakes, 60 Great Plains, 62 Mackenzie Valley, 60 Mississippi Valley, 60 narrow, 42 Pacific coast, 63 Pacific oceanic, 66 Rocky Mountain, 62 wide, 42 Rowan, William, 10