Field Guide The BirdVoice™ Field Guide is a hard-wearing encapsulated (waterproof) reference card. It has been designed to fit easily into a shirt pocket. Species are ordered alphabetically by common names for instant accessibility. There are 270 species with calls, songs and guides in a small concertinaed guide. Price £15.00. You will need to have BirdVoicePEN to enable the Field Guide DOWNLOAD: Full preview of the Field Guide Key Features: - Designed for shirt pocket - Dimensions 17 x 8 x 0.1 cm - Waterproof - Alphabetical listing for quick access