Johnny Wee documented a pair of adult Ashy Tailorbirds (Orthotomus ruficeps) feeding a recently fledged Plaintive Cuckoo (Cacomantis merulinus) at Singapore’s Pasir Ris Farmway1 in mid-July 2013.
It must have been a strange sight to witness a pair of small tailorbirds feeding a larger cuckoo fledging that was more than twice their size. The tailorbirds must have worked extra hard looking for food to satisfy the hunger of this giant fledgling. With each feed, the tailorbird placed whatever food it managed to catch into the fledgling’s gape that was wide enough to accommodate the former’s head.
Cuckoos are well known for their parasitic behaviour of laying their eggs in the nests of other birds. Such behaviour allows the cuckoos to keep on reproducing without the need to build nests or to care for their offspring.
The only other instance of such a big difference in size between a host species and a large young of a brood parasite is seen HERE where a Pin-striped Tit-babbler (Macronus gularis) feeds a Drongo Cuckoo (Surniculus lugubris) juvenile.
Other instances of interspecific brood parasitism where the size differences were less significant include the following:
1. Golden-bellied Gerygone (Gerygone sulphurea) feeding Little Bronze Cuckoo (Chrysococcyx minutillus) juvenile HERE.
3. Common Iora (Aegithina tiphia) feeding Banded-bay Cuckoo (Cacomantis sonneratii) fledgling HERE.
Note: Rajathurai Subaraj assisted in the identification of the Ashley Tailorbird.