Reddit reviews Shamanic Journeying: A Beginner's Guide

You can do it either way. Sandra Ingerman has an audio book/CD with drumming. Steven Farmer also has a power animal book with a CD/MP3 with drumming and journeying instructions (if you buy the kindle version, you'll get a link to download the MP3s).

The advantage of recordings is that you can play them without bothering others. However make sure you have headphones that don't bother you; otherwise you'll be paying attention to that ear feeling. Also if you tend to move during journeys, use headphones that will stay on...

Crows pop up a lot in myth and legend. It's possible that the archetypal crow could be a spirit guide for you. To find out more about that, give this book a read, it's quick and easy: http://www.amazon.com/Shamanic-Journeying-A-Beginners-Guide/dp/1591799430

It's also possible that it's sheer coincidence.