Does the crow keeps its egg in the nest of a cuckoo?

"Cuckoo bird" refers to an entire family of related birds. Many species are brood parasites, laying their eggs in the nests of other species, but the majority of species raise their own young. The temperate species are migratory. For species breeding at higher latitudes, food availability means that they migrate to warmer climates during the winter, and all do so. Migration (or in the case of some species - lack of migration) dictates when they nest. Mostly they build their nests when preparing to breed - which occurs most often in the summer months. There is no one particular summer month that is unique as a month for making nests.