Guttifer's Nested Checklist Theorem

Guttifer's Nested Checklist Theorem, named after pioneer lister Tringa Guttifer (read about T. Guttifer here), states that the total of one checklist area cannot exceed the total of a second checklist area, if the first checklist area fits within that second checklist area. 

Birders unfamiliar with this theorem are likely still aware of its principle. For example, Vancouver Island is part of BC and thus an individual's Vancouver Island life list cannot exceed their BC list, since any bird observed there would, by default, also represent a BC bird. BC is nested within Canada, and so it goes on.

However, the official Vancouver checklist area is an international one, and blatantly contradicts Guttifer's Nested Checklist Theorem, through the inclusion of Pt. Roberts, WA. Due to this outrageous discrepancy with one of listing's founding principles, many local birders are opposed to including anything seen at Pt. Roberts on their Vancouver list. Many players now choose to go by the new eBird Metro Vancouver County checklist area, which for all purposes is identical to the official Vancouver checklist area with the exception that it excludes Pt. Roberts. 

So where does this leave me? Pt. Roberts is a fantastic birding area offering some of the best and most easily accessible sea watching around Vancouver. I often wish it was part of BC, but then suddenly realize how quickly it would get developed, and immediately become thankful that it isn't. It would be a shame to disregard such a birding hotspot, but in order to compare apples to apples, a distinction needs to be made between birds seen only in Pt. Roberts. As such, my list will be reported as 2XX + Y, where Y represents Pt. Roberts additions. 

There are two species that are most easily seen within the Metro Vancouver checklist area at Pt. Roberts: Heerman's Gull and Ancient Murrelet. The time to see Heerman's Gulls locally is now, and in between high tides on August 3rd I visited Pt. Roberts to get my "security" Heerman's Gull.

#231 + 1. Heerman's Gull. 3 Aug 2015. Lighthouse Park, Pt. Roberts, WA.

I now plan to make a subsequent effort to see a Heerman's Gull in the Vancouver checklist area north of the border because, if for no other reason, 2XX + Y is such an ugly format for a list total.

Count update: 236 + 1 as of August 6, 2015.