Back to the obsession piece. There are all sorts of bird enthusiasts in the world. From the person who just enjoys watching the birds that might appear at a yard feeder to those that might travel to other continents to add to their sights, it all comes down to creating and maintaining lists as a dedicated birder. From the yard list to the state list to the life list, it's pretty amazing just how involved folks can get, and the wealth of citizen science that can be utilized overall.
I've always enjoyed looking at and photographing birds. And unbeknownst to me, I dove right in as more than just a casual observer without realizing it. Back in the early 1980s, I received my first SLR camera and zoom lens as a gift. And right away, I began documenting the birds seen in the yard and starting my first list - a yard list. Although I haven't been as thorough as some in keeping that yard list year by year, I instead have just kept an overall record, Guess it was just in the blood to start keeping a list to begin with. And it has been enjoyable to look back at some of the birds noting my own little trends on those species I see all the time and those that come around very infrequently.
Connecticut Ornithological Association http://ctbirding.org/index.htm
National Audubon Society http://www.audubon.org/
What Non-birders need to know about Birders