Tweets,
Wanted to respond to one thing Jim Greaves pointed out:
"only a few dozen (a hundred perhaps?) US citizens have surpassed 650 species in North America in the process, and I'd wager most of them chase every rarity they can (not even pursuing life lists, but rather regional or state lists). "

While I agree that the habit of twitching for vagrants across the country can be energy intensive, I would point out that to get to 650 doesn't require "twitching" much at all. I stand currently at 600 species. I have lived in Oregon, Washington, New Mexico for less than a year and Alaska for about a year. I have NEVER been to the SE US, including Florida and have only briefly birded the Texas panhandle and nothing of the rest of that state. I have only taken pelagics out of the west coast, so no eastern pelagics on my life list. I have never driven more than a neighboring state to chase and obviously from having not birded much of Texas or SE US, 650 for myself would be quite easy. Stating my lack of travels isn't to degrade myself, however it is to show how 600 alone can be reached quite easily, in fact 400 in Washington alone is a fairly attainable goal. It is also to show that I really don't focus on my life list, but do want memories of looking at seabirds on the Pribilofs, hummingbirds in SE Arizona, the amazing Gannet colonies in New Foundland etc.. Yes I got lifers, and eventually I'll get to Florida, not because I want to drive up my life list but because I want to see species I have never before had the pleasure of seeing in the natural habitat.
So, I would take issue that to reach a 650 or even say 670 would take cross-country twitching. For those birders well over 700, then yes this comment made by Jim applies. To get near 700 only takes some vacation travels with the US and Canada and spending time in some areas. I wouldn't call week long birding vacations to places energy intensive, any more than what millions of other Americans do on their vacations. We just choose to go to National Wildlife Refuges and other places while the rest of America goes to Disneyland other popular places.

Off my soap box now. Just wanted to add my two cents.

Scott Downes
downess at charter.net
Yakima WA