- Richardson 1937 Red-breasted Nuthatch (Sitta canadensis) June 16, 1937 - Swi. W Parkins Lake, Deschutes Co., Oregon A single bird was seen entering a hole (apparently of a woodpecker) about 25' high in the trunk of a live White Fir. This may be a nest cavity, but if so probably could not have been excavated by this species in hard live wood - or may only be a roosting cavity. This is likely for the bird entered late in the twilight and was not seen to come out! June 19, 1937 - so above - The above mentioned cavity is evidently not used as a nesting cavity for birds have not been seen around during the day. If it is assumed then that this species generally roosts in cavities, it becomes of interest to know the exact position in roosting. If the floor of the cavity were fairly wide and flat, the nuthatch could roost on it in a relaxed horizontal position. If it were vertical and narrow, the position of the bird would have to be a clinging one. This were of interest in its effect on development of leg proportions, musculature etc., for as is shown in various swift's opened tail - a perching habit alone can give rise to a marked structural adaptation,