Rfalconcam Forum

Other Nature Related Information => General Nature Discussion => Topic started by: Donna on 26-Oct-11, 07:38:27 AM



Title: The Pittsburgh Murder
Post by: Donna on 26-Oct-11, 07:38:27 AM
of Crows!  :wave:

http://www.youtube.com/watch?v=CjMHLWp-ORc#ws (http://www.youtube.com/watch?v=CjMHLWp-ORc#ws)

How to count birds: By Kate St John

Inevitably a flock this large makes us wonder:  How many crows are there?  How do you even estimate their number?  Here’s how.

   1. Note the starting time.  (For example:  5:45pm)
   2. Pick a reference point in the scenery.
   3. Use a timer and count the number of crows passing the reference point for 1 minute or 3 minutes, whichever is most useful.  Make several of these timed counts so you can get a decent average of crows per minute.
   4. Now relax and watch the crows passing by.  If their concentration increases or decreases noticeably, redo the timed counts.
   5. When the crows taper or stop coming, note the ending time.  (For example:  6:30pm)
   6. For how many minutes did the crows pass the reference point?
   7. Use some easy algebra:  minutes * crows/minute = crows.

Ta dah!

You can try this while watching Peter’s video.  Count the number of crows exiting the frame, then multiply by 40 minutes.

How many did you count?

p.s.  Dedicated crow watchers (like me) have been noticing the crows for a couple of weeks.  I predict that everyone else will notice them for the first time on November 7.  Why?  Because we’ll change the clocks (“fall back”) on November 6 and suddenly, on Monday November 7, the crows’ rush hour will coincide with ours.


Title: Re: The Pittsburgh Murder
Post by: MAK on 26-Oct-11, 03:54:21 PM
 :mini-bird: :mini-bird: :mini-bird: :mini-bird: :mini-bird: :mini-bird: :mini-bird: Just like downtown Rochester near Washington Square Park!  :mini-bird: :mini-bird: :mini-bird: :mini-bird: :mini-bird: :mini-bird: :mini-bird: