Video evidence that cuckoos farm their hosts by ejecting nestlings.

Area of Science:

• Ornithology
• Behavioral Ecology
• Evolutionary Biology

Background:

• Avian brood parasites often face competition for host nests.
• Nestling ejection by brood parasites is documented, but its purpose (e.g., farming) is debated.

Purpose of the Study:

• To investigate evidence of "farming" behavior in common cuckoos (Cuculus canorus).
• To determine if brood parasites manipulate hosts into re-nesting to increase parasitism opportunities.

Main Methods:

• Observational study of a common cuckoo and Daurian redstart (Phoenicurus auroreus) population.
• Intensive nest monitoring to document brood parasite and host interactions.

Main Results:

• A common cuckoo female was observed ejecting all Daurian redstart nestlings from a host nest.
• The host pair rebuilt their nest after the destruction.
• The same cuckoo successfully parasitized the replacement nest.

Conclusions:

• The observed behavior provides evidence for "farming" in common cuckoos.
• This strategy may be more prevalent than currently detected, requiring detailed nest monitoring.