On January 18 I posted about the large number of geese Mike and I saw at Universal Mines. I posted on eBird that we saw 20,000 Canada Geese and 500 White-fronted Geese. Of course those were estimates.
The point of the following post is to clear up in my mind that we didn’t see 10,000 or 100,000 but somewhere in between. And that the next time I come across this situation I know what type of photos and angles to shoot to get a better count.
I used the few photos I took to refine my guess. And I am confident to say we saw 30,000 geese. I think.
Here is my methodology. I arbitrarily made a box – the one with a red X – and counted the geese. I counted approximately 150. I then made other squares I thought looked like they had the same density. There were 16 of these boxes in this photo or approximately 2500 geese.
And this photo of geese just taking off is also the only photo of geese on the water on the north side. The 3 boxes have around 400 geese each or 1200 geese on the west side of the lake. The photo doesn’t show it but the geese go on to the north end of the lake. I figure we aren’t seeing the east side or the north 60% of the lake. Or another 15000 = 1200*6 *2. (Total on west side x rest of lake x the east side)
I learned from this exercise that I need to take the correct photos. Because if I had taken a photo showing the complete north side of the lake I would have a better approximation and wouldn’t have any doubts.
Any suggestions on how to count high numbers of birds such as these would be appreciated.