I've long been a naturalist, in the general sense of enjoying birdwatching or botanizing: in high school I was a naturalist for the Appalachian Mountain Club and helped the Zambian Ornithological Society's bird atlas mapping project. In college I founded the Williams Naturalists, a student group devoted to, well, going for walks and catching and identifying things.
Like many of my colleagues today, this hobby evolved into a career trying to understand the origin and consequences of the biological diversity I previously enjoyed aesthetically. I like to work at the intersection of ecology and evolution, to understand how ecological interactions between species can drive evolutionary change and how that evolution can, in turn, modify ecological processes. Much of my work strikes me as a bit more ecological than would suit Evolution, and a bit more evolutionary than would suit Ecology.
The American Society of Naturalists is the natural home for this kind of cross-cutting work, particularly work that tries to fuse an expansive theoretical view of biology with some solid empirical data. I also really appreciate the long history of the ASN as the seminal biological research society of our country.
This has a personal side to it: as a former Secretary of the ASN, I was pleased to discover that the second Secretary of the ASN (Samuel F. Clarke 1886-88) was a professor at my undergraduate alma mater (Williams College), and had himself founded a group called the Williams Naturalists.