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/ --
