Monday, December 31, 2007

What are the odds?

Part 1:

On 6 December 2007 at about 8PM, in the midst of an intense winter storm, a resident of Lilllooet, BC heard a thump on their front door. Thinking the dog wanted to come in, they opened the door to find a strange bird lying on the front porch. It later died despite their best efforts, and it turns out to be a Cook's Petrel (although similar species still need to be ruled out)! This is the first for BC and for Canada.

Lillooet is west of Kamloops, in southern interior BC. It is over 100 miles to the nearest salt water, and at least 250 miles to the nearest open ocean where a Cook's Petrel would be "comfortable". How many were blown into BC and simply perished in bogs and lakes? Maybe only one, but what are the odds that the only one happened to crash into the front door of a house? And on top of that a house where the residents would take enough interest to report it?

Part 2:

In early December 2007 it was reported on the OregonBirds listserv that a Jacksnipe had been shot by a hunter in November - a first record for Oregon and only the 6th for North America of this secretive and cryptic species. But then it was discovered that the same hunter shot a Jacksnipe in the same area of coastal Oregon in late October 2004 , making this the 7th for North America.

How many other Jacksnipes have been shot and never reported? How many are wintering along the Pacific coast of North America? Maybe none. But what are the odds that one snipe-hunter, in a single patch of coastal Oregon, could personally find about one-third of all the North American records of this species?

Part 3:

On 23 December 2007 I went on one of my infrequent birding trips to Cape Ann, Massachusetts with my son and two friends. I was aware of recent Slaty-backed Gulls in Illinois and Pennsylvania, so my expectations were up, but it was still a shock to see a Slaty-backed Gull in Gloucester Harbor - the first ever for Massachusetts. I even thought that "the" bird an hour later had a very different looking bill color, and the next day Rick Heil was able to confirm that there were indeed two Slaty-backed Gulls in Gloucester. Most amazing, just an hour or so after I saw the first one in Gloucester, Wayne Petersen and Dave Larsen found another individual on Cape Cod (they thought they had a first state record, only to find that theirs was the second ... or third, by a matter of minutes - Ouch!).

How many other Slaty-backed Gulls are scattered around the eastern US? Maybe only these few. But what are the odds that the very-thoroughly-birded state of Massachusetts would suddenly have three records? Interestingly, at Gloucester and Cape Cod, the Slaty-backeds coincided with an unprecedented invasion of hundreds of Bohemian Waxwings. It seems bizarre to even suggest that movements of these species are related, but could it be just a coincidence?


And now we enter a new year filled with possibilities....

1 comment:

NickL said...

man this gets me excited for some rarities.