According to a 2006 U.S. Fish & Wildlife Service survey, birders spent more than $12 billion nationwide on travel and equipment expenses such as cameras, binoculars and bird food.

That same report states that about 1.3 million people came to Arizona to observe wild birds. Arizona birding generated $838 million in trip-related spending the same year, bringing about $1.2 billion in revenue into the state. You might just say wildlife viewing is comparable to the combination of hunting and fishing in the United States.