Great article about shooting in the Galapogos is by Thom Hogan located at
http://www.bythom.com/Galapagos.htm . The article covers several relevant topics:
Table of Contents:
• What Will You See?
• Which Camera Should You Take?
• What Lenses Do You Need?
• How Much Film Is Enough?
• Do I Bring a Tripod?
• What's a Typical Day Like?
• Ecotourism Versus Survival
Definitely a worthwhile read.
I'd think about adding a lens with IS. Being able to get close to the subject will help the image when shooting in harsh light. You can also look at Artie Morris's website
http://www.birdsasart.com and search the bulletin archive for Galapagos. Artie shows what and how he captured his terrific images over many years of trips to the Galapagos.
Enjoy your trip.
Marc
http://www.marcschoenholz.com