Since March 1, our Austin city station has recorded 4250 night calls. The quieter station 10 miles to the west had 6372. See the attached graph showing the number of calls per hour of the night. This is for the quiet station.
This chart seems rather too convenient. I am suspicious of it. What is known about this kind of timing? The curve matches the inverse of the relative quiet of a typical night. Life is just quieter in the middle of the night. So can’t a lot of this be a detector and noise effect? Or do the birds actually fly and call more in the middle of the night? Also this data doesn’t adjust for daylight savings shift in the third week of March or the fact that dusk shifts to later times as spring progresses. What we really want to plot is the hour after dusk not the actual time. But has anyone here figured out a formula for the number of minutes each night that dusk shifts? You can google this and get a bunch of graphs but there must be a formula ..... probably involving a bunch of cosines and other witchcraft? -Mike Farmer equipment Mic – Oldbird 21c Software – Oldbird tseep, thrush, GlassOFire, Raven Pro, Excel -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.NortheastBirding.com/NFC-L_SubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/[email protected]/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NFC-L 3) http://birdingonthe.net/mailinglists/NFCL.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
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