Hi All, I monitored night flight calls on a coastal headland for two autumn seasons, 2013 and 2015, using the same methods and equipment in each year. You can see a summary table of the results here: http://www.johnfkearney.com/Glasgow_Head_Guyborough_County.html.
There was a remarkable increase in the number of warbler night flight calls in 2015 compared to 2013. While many warblers increased 2 to 7-fold, Cape May Warblers were 9 times higher and Bay-breasted Warblers 11 times higher. The latter two species are known to be Spruce Budworm dependent species and have been shown to increase substantially more than other warbler species during an outbreak. There is reported to be an increasing infestation in areas well north of my monitoring station. A possible cause for concern is that another budworm dependent species, the Tennessee Warbler had fewer flight calls in 2015. Part of the reason for this post is to suggest that there can be a utility to identifying difficult flight calls, like the zeep and double-up calls, to the species level. Of course, these identifications are not going to be correct all of the time. There is only a certain probability that they are correct. I do use measurements and certain rules in guiding my identification of difficult species. I only id to the species level when I judge there to be a relatively high probability that it is correct, although I can't as yet give an exact probability range. For those ids that I judge to have less than a high probability, I leave to the generic or family level (these are also listed in the table of results in this study). Any comments would be most welcome. John -- 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://firstname.lastname@example.org/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/ --