Marshall, 1942 Micrastur semitorquatus Lake Olomoga Heard every evening & early am. at camp - always from same spot. Also one morning one called from edge Rio San Miguel in swamp forest. 1st specimen taken by R. Stilson at the spring back of camp at dusk. It was entering a hole in a large tree about 40' up. Next specimen taken by me early am. Both birds had been calling far up the mt. but I gave imitation & they came closer. Finally the male came down to the woods at edge lake & chased a pair Caracaras then perched in dead tree where I shot it. Perches with tail down & head inclined forward. I also seen & chased from out of all the dense clumps of trees where it would alight - same posture - usually body horizontal - very strange for hawk more like Cloughalaca. Shot at it several times. Call of male: loud gawk - with downward inflection.