Chestnut-collared Swifts are aerial insectivores, spending most of the day in continuous flight, capturing insects on the wing. Often flies high and fast when foraging (Stiles and Skutch 1989), but it may descend nearly to ground level during wet weather, at least during the emergence of winged reproductive termites (Collins 1968). During foraging flights, flurries of stiff, rapid wingbeats are interspersed with glides and swerving arcs, in which the wings are held down sharply below horizontal (Stiles and Skutch 1989, Hilty 2003). Roosting behavior little known, but apparently roosts in scattered pairs or in larger groups; Rowley (1966) reported a roost that contained an estimated 300 individuals. Large groups of roosting swifts may be composed on immature and unpaired individuals (Marín and Stiles 1992). Chestnut-collared Swifts roost on the nest with incubating or brooding, and at the side of, or near, the nest during the nonbreeding season (Marín and Stiles 1992).
Little information. Chestnut-collared Swift nests, at least at times, in loose aggregations, but not in dense colonies (Rowley 1966, Marín and Stiles 1992).
Chestnut-collared Swift is at least socially monogamous. During courtship, engages in courtship chases, which are high-speed chases involving two or three, occasionally four, birds; flight during courtship chases usually is high above the ground, 100 m or higher, and "often the chasing birds engaged in twisting glades, turning and veering in unison at full speed with the wings held below the horizontal", and accompanied by "sharp, scratchy sputtering notes and dry rasping shrieks" (Marín and Stiles 1992).
Social and interspecific behavior
Chestnut-collared Swift is gregarious, usually foraging in single species flocks of 10-20 individuals, or in flocks of "up to a few hundred birds" (Howell and Webb 1995). Sometimes also associates with flocks of other species of swift, such as White-collared Swift (Streptoprocne zonaris) and White-tipped Swift (Aeronautes montivagus) (Ridgely and Greenfield 2001b), but characterized by Hilty (2003) as less likely to forage with in mixed aggregations than are other species of swift. Chiefly forages in the upper levels of mixed species flocks (Marín 1993).
Bat Falcon (Falco rufigularis) is documented to prey on Chestnut-collared Swift (Beebe 1950).