A field guide, whether in book or app form (or both), is a birder’s best friend. This is especially so when you’re visiting a new location, or somewhere that you just aren’t familiar with every single bird. You never know what you’re going to see.
But having a quality field guide for your local area or your own country is also indispensable. You might be early on in your birding journey, where identifying species is an exciting challenge (some species can take years to become familiar with!), or you might just enjoy having the detailed information that a good guide provides.
After all, modern field guides contain so much more than just species identification data and pictures. They cover breeding and best information, detailed descriptions of the differences of male, female and juvenile plumage, comparisons between similar species, and of course the ranges and subspecies of birds.
An excellent bird field guide is not just a guide but a mini encyclopedia. Many guides are updated every few years (some even yearly), to take into account changes to species known ranges, changes in taxonomy and any other new data that has come to hand from scientists in the field.
Choosing a bird field guide usually results in deciding between a number of titles. Certainly most countries have several titles that cover an entire country, while in Africa for example you’ll find guides that cover either specific countries or a certain part of the continent; since bird ecosystems don’t recognize human imposed borders.