Well... large gulls deserve at least 2-3 more plates - Caspian, American Herring, Armenian, Atlantic, Siberian. I would also wish more on HerringxGlaucous hybrids and first-summer Ring-billed.
Yellow Wagtail subspecies, Amur Falcon, Oriental Honey Buzzard, Ruppels Vulture, Lesser Kestrel female, Steppe and African Long-legged Buzzards, Ross Goose, Lesser Canada Goose, Balearic Shearwater, Ultramarine Tit, Lesser Redpoll, Western/Eastern Olly and Sykes Warbler, escaped flamingos, Elegant Tern & hybrids, Black Redstart hybrids, Cormorant subspecies...
Pelicans and cranes could get flight views like those of raptors.
More details could go on crakes, Blyth's Pipit or treecreepers.
Some Mr. Mullarney plates could do well with PhotoShop, moving pictures around the plate - his plates are sometimes overcrowded or clumped. Little Gull-Kittiwake page is an example.
Tawny Owl could get more different sounds, and calls of many species (e.g. warblers and chats) could be even more detaily described. Actually, for me call descriptions are one of greatest assets of this book.
I would like to see "Tips" section for some awkward species, like Hazel Grouse or crakes, as introduced in "Threatened birds of the world".
And, last but not least - feral Mallard x Domestic Duck and feral Muscovy could get full treatment. This is most common question which beginners ask; "I seen on a pond a duck which I can find in no book..."
I wouldn't actually mind a book growing slightly, maybe 5-10% more pages and 10% bigger format. This is not much but would greatly increase usefulness.
