My Two Cents:

I was fascinated by birds from age four at the very latest. I really got
"bit" by the bug and caught a full time obsession at age 10 (on Feb 8,
1972 to be exact). I read compulsively for at least 5 years without very
much field experience. I was also self taught - no family member or
friend showed more than a vague interest in birds. I guess that's
unusual - I hear lots of mentor stories (keep up the good work, science
teachers), but I think age 10-12 is a common time for the bug to bite.

Chris (I never claimed to be normal) Hill

PS. as a corrollary to my last statement, a story:

While on a Christmas Bird Count in suburban Westchester County, NY, my
partner (a 40ish science teacher) and I came upon a skinned skunk
carcass. Yes, we did! Don't know how it died. Drew's comment was that he
immediately knew that the party responsible for the skinning was 1. male,
and 2. between the ages of 12 and 17, because - WHO ELSE WOULD?! I had to
admit I agreed with him 100%.