Mixed-Species Foraging Aggregations and Heterospecific Attraction in Boreal Bird Communities Mönkkönen, Mikko ; Forsman, Jukka T. ; Helle, Pekka ; Monkkonen, Mikko Abstract Publication: Oikos Pub Date: October 1996 DOI: 10.2307/3545592 Bibcode: 1996Oikos..77..127M