Black-necked Stork research

["Greg Clancy" <>]

Jack,

 

You have rightly reminded me that there are other examples where there are different coloured irises in male and female birds however the differences are not as great as in the stork.  Galahs have pink (female) or dark brown (male) irises, male Sulphur-crested Cockatoos and Major Mitchell's Cockatoos have dark brown to black irises while females have red or brown irises, the latter in younger birds.  It is interesting that these birds don't show any other obvious dimorphism, which is similar to the stork. Despite these similarities it is difficult to distinguish the sexes at anything other than very close range in the cockatoos.  The yellow iris of the stork can, however, be observed at some distance.  

 

 

Regards

 

Greg