Why are cuckoo fossils relatively uncommon?

The scarcity of cuckoo fossils is primarily attributed to the group's preference for forest habitats. In the fossil record, woodland animals—particularly small birds—are fossilized much less frequently than those that inhabit open areas or aquatic environments.1

While the order Cuculiformes is not well represented, evidence suggests that cuckoos existed by the early Paleogene Period, approximately 60 million years ago.1