Rufous-collared sparrow

Rufous-collared sparrows’ breeding season begins with the arrival of the rainy season. The amount of food available largely determines the length of the breeding season.

Both parents build a cup-shaped nest, primarily using grasses and rootlets. They generally build it near the ground or in low vegetation. Once the nest is finished, the female lays two to three bluish-green eggs. Incubation lasts 12 to 14 days.

This bird can have up to two broods per year.

Hatching eggs of another species

When both Rufous-collared sparrow parents are away from the nest, it creates a unique opportunity for the female shiny cowbird (Molothrus bonariensis). She takes advantage of this moment to approach and push a sparrow egg out of the nest. She then settles in and lays one of her own eggs before quickly leaving.

While the sparrow parents return to the nest, they remain unaware and incubate the foreign egg as one of their own. This is known as brood parasitism.