Wednesday, December 23, 2009

Athol CBC (Baldwinville 12/19) and the Game

Recently, I read an article about predicting bird lists before venutring into the field,compairing it to the actual list and tallying a score. For each matching species, between predicted and actual list, you get 2 points. For each species you miss, you subtract a point and for each unpredicted species, you also subtract a point. So, finding that European rarity or lingering warbler does no good in this game....the Christmas Count compiler might feel differently.
Here is a quick example:
Predicted List .......................Actual List ..............................Points
Black-capped Chickadee.........Black-capped Chickadee ...........2
Brown Creeper...................... Blue Jay.................................... -1
American Crow.................... American Crow.......................... 2
............................................Common Yellowthroat.............-1
Totals........................ 2 points out of 6 for (33.3%).

This was the 16th time I've done this section of the Athol CBC, so that expirence should be helpful, though just a few misses will bring the score down dramatically. More on this "contest" later.
I got under way at 5:30AM with the temperature being 12 f, but fortunately there was no wind. Good conditions to owl, a mile and half walk through decent habitat for Great-horned and Northern Saw Whet yielded nothing. I listened for waterfowl, which often roost on the Otter River, but the recent snow cover and fridged weather had "pushed" these species away from this portion of the count circle.
Day break.
After the failed owling attempt, I met up with Tom and Jonathan and we began our diurnal birding along the Otter River. While some of the more common species such chickadees, nuthatches, jays, crows and so forth were found an "expected" large flock of Tree Sparrows could not been found. Some years there had been 100+ present, we only found a 1/2 dozen. A few Song Sparrows, fairly uncommon up this way in winter, was nice and a calling Purple Finch was heard as it flew overhead. While Purple Finch is a nice surprise, I had not predicted for today's list...so thats a "black mark"!
Plenty of ice, even on the faster moving stretches of the river.
Once back toward the village some of the "townies , such as Rock Pigeon, House Finch and House Sparrows, were picked up. This years total of House Finches (31) was the highest in many years, perhaps this population has recovered from the conjunctivitist disease? It might be of interest to check other CBC numbers once those are compiled and posted. We looked hard for the resident mockingbird, this miss didn't help the "test score".

Other than a single Sharp-shinned hawk, this was our only other "raptor" of the day.
Once Baldwinville was canvased, we headed up to Lake Dennison. It had been very cold the past 10 days, but previously it had been a mild late fall. Warning signs of unsafe ice were posted all along the lake, so we were surprised to see 2 guys pull ice skates from their car. The birding had been dull for the previous few hours, so we stuck around hoping for some non-avian excitement... No dice. What little sense these guys had, kept them close to shore and out of the "drink". Being half dissappointed we moved on and found our first Golden-crowned Kinglets for the count.

Some one has to be the first skaters of the season or last swimmers.
The roads to the north of Lake Dennsion were gated off for the winter, we did a one mile walk and then returned to Baldwinville in the hopes of adding a few new species or two. Eariler in the morning we'd seen a Ringed-necked Pheasant, ripped to pieces on the river ice. Upon our return, to our original starting point, we found 2 live pheasants, while we counted them (and a male found later) is beyond me why this species is countable as the state releases 40,000+ each year across the state. None the less it costs me a point on the test!

An over-exposed digi-bin shot of one of 3 pheasants in our area.
Our last "new" species of the day was Sharp-shinned Hawk, another "unpredicted" species and another minus one for the test.
Typically the Athol CBC is a good one for winter finches, but its been a very lean season for these northern "irruptives". The birder, below, had waited a long time for a grosbeak or redpoll or crossbill...and not even a siskin.

Waiting for irruptive finches? Its gonna be a lean winter for northern finches and "they stole my Bins"!
The below spreadsheet has results from all years I have done this section of the CBC, the species names HILIGHTED were my predictions (actually I had predicted 30 and missed hilighting Canada Goose, Mallard, Pileated Woodpecker and Ruffed Grouse on my speadsheet), the actual number seen is in the 2009 column. I had predicted 30 species, our team got 26, but 7 species were missed and 3 unprediected species were. So the score was 36 of a total of 60 pts for a precentage of 60%.
Predicted species.......23 X 2= 46
Missed Species.............7 X -1= -7
Unpredicted Species ...3 X -1= -3
Total Points.............................36
Percentage.......................36/60= 60%

2 comments:

Kim said...

Tom, is that your own spreadsheet you use to track your birds for various years? Very impressive! I tried doing that for a while but resorted to eBird recently as I can download it into Excel for analysis, charts, etc.

60% success rate isn't half bad at all. Love the Falcon!

Tom Pirro said...

Hi Kim,
I started the spreadsheet back in 1993 and always have for this count data. Of course when I started it, THE spreadsheet application was Lotus 123, I later converted it to excel, once that MS program came into voge. I also will enter it into ebird.