Simplify the following text for a Grade 9 native English-speaking person.
Original: Most cormorants , including nearly all Northern Hemisphere species , have mainly dark feathers . Some Southern Hemisphere species are black and white .
Simplified: The majority , including nearly all Northern Hemisphere species , have mainly dark plumage , but some Southern Hemisphere species are black and white , and a few ( e.g. the Spotted Shag of New Zealand ) are quite colourful .