Marshall, 1938 Otusflammeolus Whitake#s, June 20 I expected to be able to follow it until it arrived in its terr., there it would stop & hoot while I would be able to observe it.However,it kept retreating at alarming rt. for no less than 500 yd.,directly uphill,& was followed with gt. difficulty. Finally caught up in vicinity of lg.dead cedar.After remaining still for a while, was able to call it to me. Its hoots were very loud & penetrating, the loudest & fullest tones yet heard.Apparently great resonance. Was seen in open, close against trunk dead cdé- cedar,in axil of branch stub,20 ft high.Silent.I began to call,& it flew about me in low trees from perch to perch looking intently . Looked most often upward; expected invader to be in higher trees, the normal place. Made slight rushing of wings when flew very close,and often noise as wings touched branches as flew thru dense growth yo u young trees. When peering about,used peculiar hunching motion ,rotating effect,raising head & bending body forward. Found why this owl so wild & hard to approach - snapped twig,owl jerke d forward & flicked wings violently - intolerant of approach of ground-trvelling enemies.As elong as I kept from moving around,owl flitted about looking for source of hoots.Definite terr. reaction. Perched directly in front & began giving loud full hoots but hoarse - the usual form when another bird near. Changed gradually into clear hoots.Head pointing up,posterior pt. body contracted,then sides of throat swelled greatly at each hoot.Throat greatly distended all time,even when not calling. Seemed as if it were amplifying hoots by bringing air-sacs into play, as indicated by compression of posterior flanks. Feathers of throat continually erect from its gt. glandular(?) enlargement.Long,silence,then last heard way up hill. (Only one apparent insect flight noticed.)