I live in the state of Guanajuato, and this book helped me to identify only 1 bird of the hundreds i was seeing in the area. It left me frustrated and disappointed. All birds shared with the United States and Canada are to be found in a different guide, which you wont be able to buy in mexico, so bring one with you. I have recently started using "A Field Guide to the Birds of Mexico and Adjacent Areas" by Ernest Preston Edwards, and have been able to identify every single bird i have come across since. Altho i like it much more than the Peterson Guide, i do find the write ups lacking.. the bird song is completely omitted, which you will be able to find in the Peterson guide. From my personal experience i feel that a few guides are needed to properly identify, and learn about the birds one will be seeing in Mexico. I am looking forward to finding a complete book one day, to save me lugging around three.