Cuculinae is a subfamily of birds within the family Cuculidae, commonly known as cuckoos. This group includes various species that are found in diverse habitats around the world, particularly in tropical and subtropical regions. Cuculinae birds are known for their distinctive calls and behaviors, which often include brood parasitism, where they lay their eggs in the nests of other bird species. Members of the Cuculinae subfamily exhibit a range of sizes and plumage patterns. Some well-known species include the common cuckoo and the Asian koel. These birds play important roles in their ecosystems, contributing to pest control and influencing the breeding behaviors of their host species.