Nest parasitism in waterfowl

[lizardlips@cyberdude.com]

In Chris Bochu?s response to John Bois, he remarked that nest parasitism is 
unknown in waterfowl.

A number of species of ducks regularly parasitise other duck species on an 
opportunistic basis.  

One species, the Black-headed Duck _Heteronetta atricapilla_ of South America 
is an obligate brood parasite.  It has been recorded parasitising at least 18 
species, including ducks, but also coost and other rails, ibises, herons and 
even a caracara, a scavenging falconiform.  A difference between parasitism by 
this duck and birds such as cuckoos, honeyguides and viduine finches is that 
the young are precocial.  They make no demands on the host species other than 
for a site and warmth for incubation.  After hatching the ducklings leave the 
nest and look after themselves, leaving the host chicks unharmed.