A fallacy is something that is not true.
A Cuckooshrike is a cross between a Cuckoo and a Shrike is a fallacy. It is not true. So, what is a Cuckooshrike?
A Cuckooshrike, a Cuckoo, and a Shrike are all birds, but a Cuckooshrike is not a Cuckoo and it is not a Shrike.
It is not closely related to the Cuckoo and it is not closely related to the Shrike. They are not very similar. In fact, they are in different families.

Cuckooshrike (left), Cuckoo (middle), Shrike (right)
A Cuckooshrike is in the Campephagidae family. A Cuckoo is in the Cuculidae family. A Shrike is in the Laniidae family.
The name, Cuckooshrike, probably comes from the grey colour of many of the Cuckooshrikes. Some also look a bit like a cuckoo, and have a similar undulating flight.

Indochinese Cuckooshrike

Diederick Cuckoo

Long-Tailed Fiscal Shrike

Long-Tailed Fiscal Shrike
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM