Cuculus is a genus of birds commonly known as cuckoos. These birds are found in various habitats around the world, including forests, grasslands, and wetlands. Cuckoos are known for their distinctive calls and often have a slender body shape with long tails. One of the most interesting behaviors of some cuckoo species is brood parasitism, where they lay their eggs in the nests of other birds. This strategy allows cuckoo chicks to be raised by other species, often at the expense of the host's own offspring.