Variable Sunbirds feeding Klaas’s Cuckoo

2009 July 4
by David J. Ringer

NAIROBI, KENYA — A persistent, strident begging note emanated from the tree above our patio all afternoon. Tiny birds flew in and out, making dry ticking notes, leading me to believe that the Variable Sunbirds were feeding young. But the begging note didn’t sound sunbird-like to me. I finally got the binoculars and stepped out to investigate.

Following the sunbirds’ movements, I soon located this little creature:

juvenile-klaass-cuckoo-chrysococcyx-klaas-1

Not a sunbird! Despite terrible backlighting from the late afternoon sun, I immediately suspected that this was a juvenile Chrysococcyx cuckoo. And based on its very stubby tail and limited mobility, it seemed quite young.

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Every few minutes, Variable Sunbirds (Cinnyris venustus) arrived to feed the demanding youngster. Both male and female participated in the feeding. Chrysococcyx cuckoos, like many of their relatives, are brood parasites — they lay their eggs in other birds’ nests. The unwitting foster parents then raise a young cuckoo, usually at the expense of their own offspring.

variable-sunbird-feeding-klaass-cuckoo-2

The young cuckoo is already noticeably larger than its foster parents. Details of the bird’s plumage pattern and the fact that it’s being reared by sunbirds indicate that this is a Klaas’s Cuckoo, Chrysococcyx klaas, which often selects sunbirds as hosts. (Various cuckoo species prefer different types of hosts.)

Related posts:

  1. Variable Sunbird, Cinnyris venustus
  2. Variable Sunbird’s nectar-thieving shenanigans exposed
  3. Some that got away
  4. Flycatchers in Nairobi
  5. Answers, clues, and mysteries

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