Groove-billed Ani

The Groove-billed Ani (Crotophaga sulcirostris) is a member of the cuckoo family. This ani was named for prominent grooves along the contours of the bill. Groups of ani forage for grasshoppers, flies, wasps, ants, cicades, and cockroaches. Nesting is a cooperative activity carried out by the entire flock of anis. All three ani species are cooperative breeders in which several females lay eggs in a single nest. Several pairs may join together to build a loosely constructed twig nest lined with fresh green leaves into which all the females of a group lay eggs. One smooth-billed ani nest that belonged to a group of 15 contained 29 eggs. The most that have been found in a groove-billed ani nest were 20 eggs contributed by 5 females. Both sexes incubate bringing fresh leaves or twigs at each changeover.

Not all the eggs survive to be incubated and females compete to make sure that their eggs are the ones which survive. Competition takes the form of females rolling each other's eggs out of the nest, so by the time incubation starts there are usually broken eggs strewn over the ground below the nest. Female anis are apparently unable to recognize their own eggs, so each female rolls eggs out of the nest only up to the time when she herself starts to lay, otherwise she would run the risk of evicting her own eggs. There is a dominance hierarchy among the females in a group and the most dominant female ends up with the largest number of eggs in the nest at the time of incubation. She achieves this by starting to lay after the others.

The Groove-billed Ani is similar to the Smooth-billed Ani but has a smaller bill with a smooth curvature to the culmen and grooves (often difficult to see). They are best told apart by voice. Grackles have much thinner bills.