Doesn't surprise me. A family of 4 can get into the average city zoo for the same price as parking and ONE ticket to Disney, not even counting gas/hotel/etc.
When people first tabled and labelled everything a "economic crisis", these where my exact thoughts. If people no longer travel out of country, they are more than likely to spent their free-time and holiday time locally. What better way to do that than in a zoo or botanical garden (if a safari is not that cost effective for you)?
The Woodland Park Zoo in Seattle has had a 14% jump in attendance this year, and 17% since the award-worthy Humboldt penguin exhibit opened in May. Hopefully all of the new guests appreciate the fact that they are visiting one of North America's top 5 or 10 zoos, with loads of naturalistic enclosures, but I'm sure that many people are there simply because they cannot afford to go on expensive plane trips to various other destinations.
Many Florida zoos are booming in the middle of the economic recession. Miami Metrozoo is seeing record-breaking attendance numbers, partly due to the number of locals staying near home but also because of December's $50 million "Amazon & Beyond" set of exhibits.