The Black-capped Siskin is restricted to the highlands of Guatemala and the neighboring Mexican state of Chiapas. It occurs mainly above 2000 m, but sometimes as low as 1500 m, in pine, pine-oak-alder, and fir forests, woodlands and open habitat. Much of its natural history remains unknown. Black-capped Siskin moves in pairs, family groups, or small flocks, sometimes in mixed flocks together with congeners Black-headed Siskin (Spinus notatus), Lesser Goldfinch (Spinus psaltria), and Pine Siskin (Spinus pinus). Outside the breeding season, flocks of several hundred individuals have been observed. Favourite food sources of Black-capped Siskin are the seeds of alder trees (Alnus spp.) and thistles (Cirsium spp.).