If this is a puna then the other one must be a glossy ibis what is the size between the 2 and are they very closely related in any way (ie. are they a sub-species of each other)
EDIT -
Have Twycross ever bred any of the 2 species recently
The two are in the same genus - Glossy is Plegadis falcinellus and Puna is Plegadis ridgewayi - so they are related but as closely as two subspecies of the same species.
That is defiantly different to an Australian Glossy Ibis, but as the Glossy Ibis occurs in Australia, Asia, Europe and Africa there may be some regional differences.