Chris, It depends on where you are going and what you are looking for. Birds of Tropical Asia 3 might be of help to you. For a specific species you may have to contact the Macaulay Library at Cornell or another such institute. You could also try get in touch with BF member
hunson at Chengdu Bird Watching Society. He might be able to help you. If you are looking for species that are also found on Taiwan, I might be able to give you some help with calls but remember "regional dialect" may be a factor.