Thanks Bryan! Fascinating. Wonder what cool birds are taking a rest in SE Greenland. Rob Raker Lakewood, CO On Saturday, February 13, 2021 at 9:22:00 AM UTC-7 Bryan Guarente wrote:
> COBirders, > It has been an interesting three weeks in the eastern provinces of > Canada. Newfoundland, New Brunswick, and Nova Scotia have had an influx of > Redwings <https://www.audubon.org/field-guide/bird/redwing> (*Turdus > iliacus*; the European species, not the blackbirds we know and love). > There have been 6 different instances of Redwings spread across those three > under-birded provinces (eBird map of Redwings in North America > <https://ebird.org/map/redwin?neg=true&env.minX=-76.05414250153214&env.minY=38.24833580700198&env.maxX=-42.304142501532134&env.maxY=52.12793756350506&zh=true&gp=true&ev=Z&mr=1-12&bmo=1&emo=12&yr=all>). > > Ornithologically, this is significant. Meteorologically, this is also > significant. The Polar Vortex has been mentioned in many circles recently > in relation to the cold we are feeling Friday through the weekend. There > was a strong wobble in the polar vortex recently that led to a strongly > different pattern of winds over the North Atlantic Ocean. This has caused > a long period where there have been relatively consistent *easterly* > winds from England/Iceland to the northeast reaches of North America. This > is backwards from the normal pattern of westerly (from west to east) winds > we expect to see in the Mid-latitudes. > > In all of the following web links, make sure you remember that this is on > a globe, so you will need to orient yourself appropriately to the > latitude/longitude lines to understand the winds. > > Here's an example of the backwards pattern: > > https://earth.nullschool.net/#2021/01/27/1100Z/wind/isobaric/850hPa/orthographic=-29.90,55.54,835 > > Sighting #1 showed up in New Brunswick for a two hour period then > disappeared (1/21). > > https://earth.nullschool.net/#2021/01/20/2000Z/wind/isobaric/850hPa/orthographic=-30.97,52.95,835 > . > > Sighting #2: showed up in Newfoundland on 1/25 in St John's: > > https://earth.nullschool.net/#2021/01/24/1900Z/wind/isobaric/850hPa/orthographic=-30.97,52.95,835 > > Sighting #3: showed up in Newfoundland on 1/29 in Stephensville: > > https://earth.nullschool.net/#2021/01/28/2100Z/wind/isobaric/850hPa/orthographic=-30.97,52.95,835 > > This one makes meteorological sense, but it isn't a strong case. I am > guessing this one was already local and showed up to where someone reported > it. > > Sighting #4: showed up in Maine on 2/1: > > https://earth.nullschool.net/#2021/01/31/2100Z/wind/isobaric/850hPa/orthographic=-30.97,52.95,835. > > This one is another case of possible dispersion to somewhere that it was > reported at a later date than when it probably showed up. But we are still > in the same type of weather pattern with winds out of Iceland/England which > would dictate some movements like this if a bird leaves those > island nations. > > Sighting #5: showed up in Wolfville, Nova Scotia on 2/3: > > https://earth.nullschool.net/#2021/02/02/1900Z/wind/isobaric/850hPa/orthographic=-30.97,52.95,835. > > This is a more typical winter pattern for the North Atlantic and NE North > America. This seems to be a wandering of one of the birds already in North > America in my mind. The wind pattern was NOT conducive for more Redwings > to be coming to this side of the pond. > > Sighting #6 and #7: showed up on the same day (2/12) in Crystal Crescent > Beach, Nova Scotia and in Crow Neck Beach, Nova Scotia: > > https://earth.nullschool.net/#2021/02/12/0500Z/wind/isobaric/850hPa/orthographic=-30.97,52.95,835 > > And as a weird side note, there has also been a Redwing that showed up in > Victoria, British Columbia yesterday (2/12) as well. There are two > subspecies of Redwing (*T.i.iliacus and T.i.coburni*). If these birds > are identified to subspecies, it would be interesting to see if the British > Columbia bird is of the *coburni *subspecies as that one breeds in > Iceland and winters in far western Europe as opposed to the mainland > Eurasia subspecies *T. i. iliacus*. Either subspecies is possible in the > US/Canada, but the *coburni *subspecies would be exceptional in British > Columbia and would lead one to believe that this bird likely crossed the > entirety of the Atlantic, THEN all of Canada to reach the B.C. coast. It > isn't that likely from the wind pattern, but possible. It is much more > likely that the B.C. bird is of the other subspecies and likely came from > Asia rather than Europe. > > Hopefully this was fun arm-chair birding while it is cold out. If there > are any questions about this, please ask. This is a fun time to explore > old records and dig in on winter vagrants. > > Good birding to you, > Bryan > > Bryan Guarente > Meteorologist/Instructional Designer > UCAR/The COMET Program > Boulder, CO > -- -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. 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