It describes its attacks on the Great Green Macaw when competing for nest-sites in Ecuador

I have included this article by Bernabé López-Lanús on the Collared Forest Falcon (Micrastur semitorquatus) because of the interesting description of its attacks on the Great Green Macaw (Ara ambigua) when competing for nest-sites in Ecuador. One of the main competitors of the Hyacinthine Macaw for nest sites in the Pantanal is - according to the field research of Neiva Guedes - the same species of falcon. Neiva has installed several hundred artificial nest boxes in recent years, which are used by several species, including the falcon. This takes some of the competitive pressure off the Hyacinthine Macaws, which tend to prefer natural nest sites. I took this photo of a falcon in an artificial nest box during my visit to the project in January 1999.