Because of their great height, towering above the level of the surrounding tree-tops, cottonwoods are preferred look-out perches of certain of the larger birds, notably red-tailed hawks (_Buteo jamaicensis_), barred owls (_Strix varia_), and crows (_Corvus brachyrhynchos_). Flocks of robins (_Turdus migratorius_) and of rusty blackbirds (_Euphagus carolinus_) preparing to roost have been noted habitually to gather in the tops of tall cottonwoods. In spring, large wandering flocks of goldfinches (_Spinus tristis_) have been seen feeding on the leaf buds of cottonwoods. Baltimore orioles (_Icterus galbula_) and yellow-billed cuckoos often forage in cottonwoods. Red-bellied woodpeckers (_Centurus carolinus_) spend a disproportionately large amount of their time in cottonwoods. These woodpeckers have been observed nesting in the hollow branches on several occasions. Downy woodpeckers (_Dendrocopos pubescens_) also have been noticed foraging in cottonwoods on many occasions. Certain large isolated cottonwoods along creeks were favorite stopping places of blue jays (_Cyanocitta cristata_) which, on trips from one wooded hillside to another, usually perched briefly in the tops of these tall trees. Calling and looking about, the jays seemed to maintain contact with distant mates or members of the flocks by using these high perches. Often after a brief pause in the top of the cottonwood they flew off in a new direction. Both woodrats and opossums have been known to utilize hollow cottonwoods as dens. Fox squirrels have been seen climbing in cottonwoods occasionally. #Juglans nigra.#--Black walnut is one of the more prominent hardwoods. Under original conditions, evidently many of the larger trees were of this species. Being the most valuable timber species of the area, walnut has been subjected to heavy cutting over the past 85 years. Most of the walnut trees still present are small or medium-sized, but the species is still abundant over much of the area. Along certain hilltop edges there are groves of walnuts, growing in nearly pure stands, with an occasional elm, ash, coffee-tree or honey locust. Elsewhere walnut trees are more scattered, but are distributed throughout the woodland. Although the walnut trees growing in woods are of various sizes from those of mature size down to saplings, seedlings are to be found mainly in fields near the woodland edge. In these situations it is one of the more prominent of the woody species invading open lands. The seeds evidently are transported mainly by rodents, especially fox squirrels.