Egg Ejection in the Black Swift (Cypseloides niger)

<p><span>This article documents a deliberate egg ejection from a Black Swift nest. At 13:32 hours on June 25, 2023, the egg was laid, as captured by a surveillance camera with infrared capabilities at Box Canyon Falls, Ouray, Colorado. Unusually, from June 25 to July 1, the male was never at the nest, so incubation was performed only by the female at night, the egg remaining uncovered all day for 6 days while the female foraged. On July 1, a male (unmarked but presumed to be the nest mate of the female) returned to the nest and sat on the nest cup and egg. The female arrived a few minutes later, appeared agitated and performed a hostile wing-raising display, and aggressively pecked at the male's face and head until he moved aside, placing much of his body in a crack at the left side of the nest. The female then focused on the nest cup and the egg, repeatedly trying to move the egg closer and grasp it in her beak. At 20:41 hours, the female picked up the egg in her beak and quickly tossed it over the side of the nest.&nbsp;</span></p>