Mike and group, I always thought that it was pretty easy to discern between bats and birds with my 30x scope. Maybe that only applies to close bats and that assumption needs to be reevaluated. Anyway this is a great topic and I would be interested in participating in an organized moonwatch effort. Best regards, Thomas Greg Bucks County PA
--- On Fri, 9/4/09, Michael Lanzone <[email protected]> wrote: From: Michael Lanzone <[email protected]> Subject: Re: [nfc-l] Moonwatch question To: "David Mozurkewich" <[email protected]> Cc: "[email protected]" <[email protected]> Date: Friday, September 4, 2009, 7:04 AM Hi Ted, et al., Good question! While like David said bats often fly irregularly and the wrong direction, Some nights, especially later in the night, most of the bats I see are all going the right direction and flying directly. Because I am using a scope I can ID them ok, but now that my 3 year old daughter is into moonwatching with me I only get use of the scope some of the time and use my binoculars when she is watching. I quickly realized how many birds are missed and how dificult it is to tell a bird from a bat at a lower magnification. I tried both 8 and 10 power bins and although the 10s were better, I could not always detect birds my daughter was seeing and/or definitely assign bird/bat. So that sparked the next experiment , different zoom levels on my scope. It makes sense, but I saw more birds at 60x than at 20x. Also again, more birds with a polarizing filter on the end, this was also easier on the eyes. So where does that leave us? Well definetly we need much more thought of optics used and how to assign some type of detection probability. I have some ideas on how to do this, Ted you might be in a good position to immediately test this with your class this wekend! Anyway, something to ponder as we gear up to do this on a larger scale. Talk to you all soon, Mike Sent from my iPhone On Sep 4, 2009, at 6:30 AM, David Mozurkewich <[email protected]> wrote: > On Fri, 2009-09-04 at 02:53 -0600, Ted Floyd wrote: > >> I should think that, given distant and fleeting views of such animals, >> there's the potential to over-count birds by accidentally counting bats >> and moths. Any pearls of wisdom on this one? > > Ted, > > All the birds are flying the same direction while other critters have > random flight paths. This eliminates most false alarms and is good > enough except when the birds are a minority of your detections. > --David Mozurkewich > Seabrook, MD USA > > > -- > NFC-L List Info: > http://www.NortheastBirding.com/NFC_WELCOME > http://www.NortheastBirding.com/NFC_RULES > > http://www.mail-archive.com/[email protected]/maillist.html > -- -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/[email protected]/maillist.html -- -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/[email protected]/maillist.html --
