ML475455111

Age

Not specified

Sex

Not specified

Observation details

The main roost was easily visible from the bridge, and I had good views in all directions with my scope. I could see birders in a small boat watching the same roost as I was north of the bridge. Estimated by the 1000 when they were mostly flying around before settling down in the phrags. I counted to 100 a few times to calibrate, and I did some counting in my photos to make sure I was in the right ballpark. 400-500k were reported here two nights ago and it shouldn't be peak yet, so I'd expect numbers to be higher tonight than they were two nights ago, but I believe my number is reasonably accurate. Perhaps I hit it on a bad day, though I imagine numbers are at least vaguely similar night to night. I'm curious what methods were used to estimate the larger numbers recently and in the past. Certainly low tens of thousands and I could imagine 100k+ at absolute peak, but I wonder about the reports of many 100s of thousands in the past few years, especially when the photos attached to some of those reports don't seem all that overwhelming and don't seem to support such high estimates, and mostly look on par with what I witnessed tonight. I know what 100k birds looks like and this did not seem close to it tonight, let alone 500k. Perhaps my estimates are low (it was difficult to estimate; my clicker was useless and it was impossible to do rate of passage, count based on photos given the low light and distance, or other more accurate estimation techniques) and it could have been a bad night. A fun evening but not the spectacle I imagined based on the reported numbers. I'll probably come back on another night and see if it compares, in case I somehow overlooked something obvious tonight or the chance it was a drastically "off" night for the roost. The photo shows about 990 martins. At peak there may have been 8-12 times that in the air over the roost, plus maybe a similar number landed (though that might be low), and a few thousand milling around downstream too.

Technical information

Model

Canon PowerShot SX70 HS

Lens

3.8-247mm

ISO

800

Focal length

151.3 mm

Flash

Flash did not fire

f-stop

f/5.6

Shutter speed

0.01 sec

Dimensions

5184 pixels x 3888 pixels

Original file size

6.91 MB