Birds of Britain A Field Guide to British Birds
The Owl Pages Everything you might want to know about Owls
Handbook of the Birds of the World: Internet Bird Collection A collection of more than 7,500 video clips of nearly 2,500 different species of bird
The Arachnology Home Page The Arachnological Hub of the World Wide Web
2500 links to sites with info and pictures of spiders and other arachnids
North American Bird Sounds Recordings of bird song from Northa America
Animal Diversity Web Brief but very useful descriptions with pictures and taxonomic infomration on many animals from the University of Michigan Museum of Zoology
Sharpe Shells A commercial site with illustrations of hundreds of sea shells

Tree of Life

An excellent guide to taxonomy though only parts are done
Integrated Taxonomic Information System An authorative taxonomic website