Related by context. Frequent words. (Click for all words.) 64 wolves roam 50 nesting seabirds 50 Jurassic Period 50 ancestors migrated 49 Cretaceous Period 48 prairies 47 Late Triassic 47 southward migration 47 conifer forests 46 chestnut blight 46 grassy plains 46 sparsely settled 46 temperate forests 45 Mormon pioneers 45 Beringia 45 Late Cretaceous 45 coniferous forests 45 Sandhill cranes 45 beaver pelts 45 tallgrass prairie 45 tundra swans 45 pronghorns 45 temperate rainforest 45 Upper Paleolithic 45 migratory songbirds 45 Boreal forest 45 Gambian rats 44 wintered 44 mostly ethnic Tutsis 44 Bering Straits 44 Atlantic Flyway 44 subarctic 44 ringnecks 44 westward migration 44 interbred 44 Fertile Crescent 44 trumpeter swans 44 Gypsy moths 44 red cedars 43 nesting bald eagles 43 Selkirk Mountains 43 Bighorn Basin 43 double crested cormorants 43 dinosaurs roamed 43 roamed 43 Pleistocene 43 Mesolithic 43 Conata Basin 43 buffalo herds 43 boreal 43 sparsely inhabited 43 migratory bird species 42 colonized 42 Infestations 42 buffalo herd 42 Greater Yellowstone Ecosystem 42 blue winged teal 42 Hutu moderates 42 Early Cretaceous 42 bison herds 42 endangered mammal 42 Volcano erupts 42 wintering grounds 42 hunter gatherers 42 extirpated 42 Gondwanaland 42 pygmy rabbits 42 bison 41 intervened militarily 41 bobwhites 41 migrating 41 migrated 41 temperate zones 41 Whooping cranes 41 redpolls 41 hardwood forests 41 fur trappers 41 Mesoamerica 41 snowy owls 41 gadwall 41 Pleistocene era 41 Whooping Crane 41 prairie 41 resettles 41 searchers scoured 41 Gila Wilderness 41 cottontail rabbits 41 Raton Basin 41 mastodons 41 exterminated 41 steppes 41 savannahs 41 white fronted geese 41 migrations 41 deciduous forests 41 bison elk 41 Palaeolithic 40 inhabited 40 coexisted peacefully 40 peopling 40 sandhill cranes