The two best tools are ZipGuides and the advanced search:
ZipGuides allow you to view the wildlife of an area (U.S. only) based on a zip code. This helps you identify which of the species in our extensive field guides you were most likely to have seen in a given area.
In addition, the Advanced Search feature on eNature allows you to submit information on a variety of characterisitics you may have observed (e.g. color and size), thus greatly narrowing the possible species.
You may also find additional useful information by searching the Ask an Expert library.
We hope this helps,eNature Staff