We didn't use guides - other than in the Mangrove.
Field Guide - Birds of Mexico & Central America - Ber Van Perlo
Where to find birds - A Bird-finding Guide to Mexico - Steve Howell ( a little out of date now but a good resource nevertheless.)
Mangrove guide - San Blas - Chencho ( 323 28 50716 - or he can be found by asking the boatmen that hang out and the stand on the right hand side of the road just before you cross the bridge on the way back out of town.)
Ocean trip and Peso Island - Pato or call 323 285 1281
Bird song - can be ordered form www.birdsounds.nl
Lonely Planet Guide for points of interest.
Make sure you see out Tips and Resources pages - and feel free to contact us for more information.