Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Pelecaniformes
Family: Phalacrocoracidae
Genera: Phalacrocorax
Species: Melanoleucos
Scientific name: Phalacrocorax melanoleucos
Common name: Little Pied Shag, Little Shag, White-throated shag, Little Cormorant,  Kawau paka, Little pied cormorant, Little black cormorant, Kawau tūi

Phalacrocorax melanoleucos (Little black shag) is a common waterbird, found around the coasts, islands, estuaries, and inland waters of New Zealand, Malaysia, Australia, New Guinea and Indonesia, and around the islands of the south-western Pacific and the sub-Antarctic. It is a small short-billed cormorant which varies in colour from all black to pied (black and white) with a short stumpy yellow bill and small crest,  The mostly black white-throated form predominates in New Zealand.
There are three subspecies recognised in New Zealand. There are three subspecies are recognised whose different plumage forms freely interbreed.
Phalacrocorax melanoleucos (Little black shag) tail is longer than the Phalacrocorax carbo (Black shag).

Phalacrocorax melanoleucos Little Shag Kawaupaka.JPG

A Little black shag drying its plumage after diving. It has it has no oil glands and hence the feathers get wet so there is no buoyancy and it can submerge easier.Phalacrocorax melanoleucos Little pied cormorant-6.jpg

 Thanks to Wikipedia for text and information     https://creativecommons.org/licenses/by-sa/3.0/