What a find! First for the ABA region, a female Sungrebe showed up in New Mexico. The bird was photographed on the 13th of November, and correctly Identified the 17th then refound the 18th. What a beautiful bird. Beautiful on behalf of its colors, and because of its shear rarity in the ABA area. See photos here.
Also a Lucy's Warbler in Fort McMurray, northern Alberta. The bird stayed from november 8-10. What a wacky spot for a arrid country warbler to be. Makes you wonder how many rare birds are we missing.
My theory is that it depends on several factors.
- Area of appropriate habitat
- Number of birders visiting that area
- Number of birders that know what they are looking at
- Densitiy of birders
- Hourly coverage of the appropriate habitat
So with all that, and more, in a estimantaly equation, we can kind of guess the number of birds we miss. It is all very complicated, but there are some basic rules. The more heavily birded the habitat is, the more rarities are found, and vica versa. So take Monterey Bay pelagic trips. Very active, good habitat, and lots of coverage, and they see some rare birds. More then you would if you visited a dock and scanned the ocean once a week.
To answer the question, this year the ABA has had 3 new birds. I think 10% or less of rare birds are ever found. so that makes about about 30 potential brand new birds for the ABA that were missed. Lets add about 2 to the missed column in honor of Attu Island. After its tours were closed, we miss much more birds.
So, the moral of the story is, get out there and look.