Re: [nfc-l] When does night end?
Dear all, thanks for all the input, references and answers. Yes, it is indeed quite clear in real life when night ends and it is good to see that the formal limits agree. In my parts of the country the first sign of the night getting to an end is a 1 hour chorus of pygmy owls, followed by (the proper) Robins and blackbirds. Around the start of blackbirds calls is where my local night appears to end. This is some 45 minutes before sunrise (twilight is somewhat longer at 60degN than say at 40degN). This definition is potentially problematic in late May when the last arctic migrants head for the tundra - there is almost no "proper night" at that time here. And slightly off the migration topic. This past June/July we intentionally birded in Lapland (70degN) with my son at "night time" because of lower levels of background noise for recording. Despite of the midnight Sun being above the horizon we were impressed how most of the birds were completely silent (slept) for the "darkest" 3-4 hours. Thanks for the discussion Harry Lehto Finland hle...@utu.fi -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES Archives: 1) http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html 2) http://birdingonthe.net/mailinglists/NFCL.html 3) http://www.surfbirds.com/birdingmail/Group/NFC-L Please submit your observations to eBird: http://ebird.org/content/ebird/ --
[nfc-l] When does night end?
Hi, in discussing night flight calls I am a bit confused about the concept of "night". Astronomically, I have no problem with the true night, and the various twilights. If the limit of "night" is taken at sunset/sunrise, then various day birds fall into the category of night flight calling birds even if they are not proper night migrants. Tits (chikadees), crows and finches start to vocalise before well sunrise, during the civil twilight, and gererally they do not crowd the sky in the deep hours of the night. There appears also to be an assymetry between dusk and dawn. During the same light conditions the duirnal birds at dusk tend to be much quiter than at dawn, so this is not that miuch of a problem in the evening. My question is when do you guys consider the night over? Regards Harry hle...@utu.fi Finland -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES Archives: 1) http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html 2) http://birdingonthe.net/mailinglists/NFCL.html 3) http://www.surfbirds.com/birdingmail/Group/NFC-L Please submit your observations to eBird: http://ebird.org/content/ebird/ --
Re: [nfc-l] Moonwatch question
Mike et al, to your point.. >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 only limited experience with moonwatching, but can make some comments as an astronomer. Consider a full moon. It shows a contrast to the adjacent background. For all purposes of Moonwatch the surrounding sky is informationless and "black", so an optimum field of view would be such that the moon fills the whole field of view. The moon itself is not really that bright. It is actually quite close to the brightness of green grass in daylight. To alleviate the "large contrast problem", you could be better off if your vision was **not** dark adapted. I would actually observe the moon in conditions were the back yard lights and city light ;-) are on and not switched off. Quite different from standard astro observing in that sense. Because the moon is a celestial body it moves its diameter in 2 minutes with the rest of the sky. This creates a problem as one should really be tracking the moon with a proper setup mount. If a tracking mount is not available then one could obtain a 1 minute nonstop stare if the magnification were such that it covered 2/3 of the diameter of the moon. Then a few seconds for repositioning etc. I would guess that having the telescope still for 1 minute would be better than manually trying to follow it all the time. Regards Harry J Lehto -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html --
[nfc-l] Tenglmalm/Boreal Owl autumnal call
Hi, for the type of call that Tengmalm's/Boreal Owl (Aegfun) makes when they are moving about is now downloaded at http://www.tarsiger.com/sounds/index.php?lang=eng Regards Harry hle...@utu.fi -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html --
Re: [nfc-l] First recording ... rails on migration
Rob and others, The Tengmalms/Boreal Owls (Aegfun) wer enot heard by Janne but by a couple of other people. One of them is close to the North end of the gulf of Bothnia. The Tengmalm call is by description the same as what I call (somewhat incorrectly the Whip call - I'll try to get it uploaded to www.tarsiger.com later tonite). As for the three crakes Janne heard (of course on different nights), he mentions that they gave calls similar to normal territorialal calls, so that there was no question about the id. Maybe this answers partailly at least your question about spotted's call type in flight. Regards Harry - Harry J Lehto, Ph.D., Adj. Prof. Tuorla Observatory Department of Physics and Astronomy University of Turku Väisäläntie 20 FI-21500 Piikkiö FINLAND hlehto(a...@sign)utu.fi -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html --
Re: Re:[nfc-l] First recording ... rails on migration
Michael and others,
After my last email to the group Magnus Robb inquired
about the Spotted Flycatcher (Musstr) I mentioned, so I sent out an inquiry to
the Finnish birdnet about what migrants birders had heard. Among others Spotted
was "confirmed" although undocumented by recordings - hope that this will be
done soon. A couple of other interesting records came into moonlight. One such
is that when Tengmalm's Owls (Aegfun) are on the move they stay in contact at
night by calling - you can hear a flock moving by on a wide front. It was not
confirmed whether they do this calling during flight of if they sit down to
make these autumnal contact calls.
Now getting to the main point about Rails. I got a note from Mr. Janne Aalto,
who lives in Parikkala just next to the Russian border close to a good Rail
site Siikalahti. He told me that he had heard three rail species in flight:
Water Rail (Ralaqu), Spotted Crake (Porpor) and a Corncrake (Crecre). He was a
bit cautious in calling these night migration calls, but he told that the birds
were all definitely flying and wondered whether they started their display
calls ("songs") when they felt that they were approaching a familiar display
site. The Corncrake was apparently further up in the sky. I have personally
heard coots (Fulatr) and moorhens (Galchl) call during full migration.
These sounds quite similar to your yellow rail observation.
regards
Harry
hle...@utu.fi
Finland
-
Harry J Lehto, Ph.D., Adj. Prof.
Tuorla Observatory
Department of Physics and Astronomy
University of Turku
Väisäläntie 20
FI-21500 Piikkiö
FINLAND
hlehto(a...@sign)utu.fi
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RE: [nfc-l] Request from the UK
Dear all, quite interesting to read about flights of rare vargrant such as swainson's thurshes or yellow warblers. Where I do some monitoring I have had rather quiet nights in the last week. Some Black-bellied Plovers (Plusqu), Ringed Plovers (Chahia), Tree pipits (Antpra), Spotted flycatchers (Musstr) and the very first migrating Red-wing (Turili) of the season, and also a number of unid's calls. As you may have guessed already, I am located in Europe a bit North of UK. Now a short question relating to some previous mails. In addition to Raven pro (which is sort of expensive), syrinx (which I cannot get to work) and Tseep-x are there any freeware programs which could be useful for searching calls from large files? regards Harry Harry J Lehto Kaarina, Finland -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html --
