How does a newly hatched common cuckoo remove host eggs and nestlings from a nest?

Within a few hours of hatching, the young common cuckoo exhibits an instinctive behavior known as nest-mate eviction to eliminate competition for food from the host's offspring.12

The process occurs as follows:

• Positioning: The blind, naked cuckoo chick works itself underneath the host's eggs or other nestlings.1
• Heaving: Aided by a specialized depression located between its shoulder blades, the young cuckoo lifts the object onto its back.1
• Ejection: The chick then maneuvers the object to the rim of the nest and heaves it over the side.12

By repeating this action, the young cuckoo ensures that it remains the sole occupant of the nest, allowing it to receive the full attention and food provisions from its foster parents. This behavior is typically completed within 24 hours of the cuckoo hatching.1