Sunday, February 16, 2014

Bird traces

How many birds are in my sky?  - And maybe some UFOs?

To answer this question I used a cheap webcam (Logitech C310) and two pieces of software:
  • UFOCapture is a video motion capture software that starts recording on a hard disk drive of a computer a few seconds before a change in the picture to a few seconds after a change in the picture.
  • Yawcam is a static picture caption software with options for periodic captures and motion detection.
The software is sensitive enough to detect birds in flight and it recorded their flight paths correctly. Below I enhanced the paths manually to make them more visible.
Unfortunately I did not get a stable performance but I'm sure it's a hardware (webcam+laptop) problem and not a software problem, because I had similar problems with Yawcam. Many video recordings were incomplete or showed just static pictures (no motion). But the (few) successful video recordings were very impressive. 

I didn't get enough data to count the birds in my sky. But from the video's I noticed some things. Some are blindingly obvious in hindsight, but it's good to be reminded of them:
  • Few birds fly high. Most birds stick to the ground.
  • It is difficult to catch birds in flight.
  • Birds fly very quickly through my sky. It takes them less than 1 second to pass through the field of view.
  • There are not many birds in the early morning sky. And most detected birds are individuals, there are no flocks.
  • Birds are very small in the sky. I recognised seagulls and pigeons. Their flight patterns are easily identified. But otherwise it's difficult to determine the species.
The software is relatively stable but it has very limited functionality. The motion detection is not sensitive enough to detect birds in flight. So I set the software to take periodic pictures (1 picture per minute) and I caught:
  • 26-12-2013 from 11:26 to 12:41 (75 minutes) looking North: 5 birds (4 seagulls, 1 unknown)
  • 26-12-2013 from 15:19 to 17:39 (140 minutes) looking South: 18 birds (7 unknown, 1 unknown,  3 seagulls, 1 unknown, 6 jackdaws going to roost)
  • 29-12-2013 from 12:20 to 17:30 (310 minutes) looking Southwest: 34 birds (1 unknown,1 magpie?, 4 jackdaws?, 24 seagulls, 1 airplane, 1 seagull, 3 jackdaws going to roost at 16:50)
  • 31-12-2013 from 13:31 to 17:19 (218 minutes) looking Southwest: 1 bird (1 seagull), probably an anomalous result because of the fireworks all day long
  • 1-1-2014 from 14:26 to 17:09 (163 minutes) looking North: 15 birds (15 seagulls)
Conclusion and further research
  • Webcam pictures of the sky are always beautiful.
  • A bird in the sky adds depth and perspective to the sky. Do you know that magpie in the Breughel painting?
  • Cheap webcams and free software are not sensitive enough for birdwatching and UFO hunting.
  • Most of our birds are seagulls and a few jackdaws. Seagulls circle in the sky so they are easier to catch.
  • If you look up 10 times you will see an airborne bird once. (But a human eye has a much wider view than the webcam, so you will probably see more birds.)
  • What setup would I need to catch our other birds (ducks, coots, blackbirds, robins, magpies)? Better resolution? Point the webcam at the ground? Install a bird feeder?
  • I could determine the most likely times to see a bird in the sky. My subjective feeling is that I see more birds in the morning and early afternoon than at other times.
26 December midday (includes the single pictures above)
26 December evening
29 December afternoon
31 December afternoon
1 January afternoon
Sources: - UFOCaptureV2, V2.24, 2013/06/09

1 comment:

  1. Lovely images! I suppose sometimes successful birdwatching is also down to the location, since birds tend to have their own habits. One video work I really like is Laurent Grasso's Les Oiseaux in which he appears to be just shooting a long video of a sky in Rome with some "smear" in it. Eventually it becomes apparent that it is not a weird digital smear but actually a huge flock of starlings moving in the sky. The footage of it was amazing.

    I'm sure if you use a better camera you can get better results even with the same software. The PS3 Eye is slightly better than most webcams because it was made for specifically for motion capture, but if you have a bigger budget then maybe a GoPro is better (and also small and versatile for other outdoor/mobile shooting purposes/tying it to your dog or cat's collar to see where it has been going)...