I have also noticed that there have been a number of days this season in which there was good migration reported on the ground, but relatively low densities seen on radar. While the variation of wind direction at different altitudes may offer a path for birds to migrate on nights that the predominant winds are not favorable, It still doesn’t explain why more birds are not showing up on radar. Are they migrating so low that they fly “under the radar”? Do they have some sort of natural “stealth” mechanism to avoid showing up as reflectance? Or are the numbers still relatively modest but local weather circumstances are just concentrating them in certain of our parks?
It will be interesting to see what we see on the ground when the densities pick up a bit. Peter. On May 2, 2016, at 3:57 PM, Sean Sime <s...@seansime.com> wrote: > > I was fortunate enough to see the male Cerulean Warbler in Prospect Park this > morning and equally fortunate to be standing near Karen Ohearn when she said, > "I've got a Yellow-throated Warbler!" > Both birds were near the southern terminus of the Lullwater adjacent to the > winter bird feeding station. A checklist with ID quality photos can be seen > here. > > http://ebird.org/ebird/view/checklist?subID=S29356904 > <http://ebird.org/ebird/view/checklist?subID=S29356904> > > For those on the list that watch radar and wind maps, last night offered a > true 'teachable moment." The surface winds were from the NE and SE overnight. > There was no visible lift off north of Virginia on radar maps as of 10:30pm > and no measurable drop out this morning at 5:30am. > > I use this radar link: > http://radar.weather.gov/Conus/northeast_loop.php > <http://radar.weather.gov/Conus/northeast_loop.php> > > And this wind map: > http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-76.16,41.82,2048/loc=-73.010,40.993 > > <http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-76.16,41.82,2048/loc=-73.010,40.993> > > Given what was visible (to me) I decided to not be out first thing. As tweets > from Prospect Park starting coming in it was clear birds moved last night. So > curiosity prompted some conversation. What Shane Blodgett was kind enough to > point out was on the wind map I use one can search by elevation. By clicking > the "earth" icon in the lower left corner of the wind map you can change the > height for the wind readings. I have more research to do, but by changing the > height to 850 (this is a pressure reading, but correlates with the altitudes > birds migrate at) I could immediately see the mid-level winds were from the > SW overnight and provided an explanation for the influx of birds in the park > and along the coast this morning. > > If other list members have more/other sites they find useful in this regard > please share. The technology and information accessible at our fingertips is > exciting! > > Good birding! > > Sean Sime > Brooklyn, NY > > > > > > > -- > NYSbirds-L List Info: > Welcome and Basics <http://www.northeastbirding.com/NYSbirdsWELCOME> > Rules and Information <http://www.northeastbirding.com/NYSbirdsRULES> > Subscribe, Configuration and Leave > <http://www.northeastbirding.com/NYSbirdsSubscribeConfigurationLeave.htm> > Archives: > The Mail Archive > <http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html> > Surfbirds <http://www.surfbirds.com/birdingmail/Group/NYSBirds-L> > BirdingOnThe.Net <http://birdingonthe.net/mailinglists/NYSB.html> > Please submit your observations to eBird <http://ebird.org/content/ebird/>! > -- -- NYSbirds-L List Info: http://www.NortheastBirding.com/NYSbirdsWELCOME http://www.NortheastBirding.com/NYSbirdsRULES http://www.NortheastBirding.com/NYSbirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/nysbirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/NYSBirds-L 3) http://birdingonthe.net/mailinglists/NYSB.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --
