Linda Hibbin, Graham Searll and myself were at Kirstenbosch this morning (Friday 3 May) and at a tree we have named the cuckoo tree, as all the larva of the Garden Acrea Butterfly have attracted so many Klaas's Cuckoos, we observed a fascinating interaction.
Both adult and juvenile cuckoos were present, and today we watched a male chasing a female all around the area. Every now and then she would stop on a branch, utter a strange call, and he would immediately pop a caterpillar into her bill! The strange call from the female and interaction attracted some Sombre Greenbuls who then followed the cuckoo pair in a procession through the tree tops!
I couldn't imagine the cuckoos would want to breed now, but on the other hand, the Sunbirds are starting to breed and perhaps the Cuckoos see them as potential hosts?
I can't find any reference to Klaas's breeding in winter in the Western Cape, as their hosts are mainly Prinias and other birds that only breed in spring or summer - so why would this pair be showing this behaviour unless our winter breeding sunbirds are actually their host parents?