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n style=3D'font-size:12.0pt;fon --_000_C8D7A39694DA4A70826A75980A89B229dalca_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Hi John, I=92ve seen a couple of groups of ~20-30 Am Goldfinches passing through our= yard in Halifax recently, feeding high in the trees plus visiting feeders,= twittering away, then moving on after a half hour or less. I had assumed = that these were migrating groups en route, but this species never seems to = figure in your flight call lists. Does this mean that they really are in the business of migrating now but do= so silently so you miss recording them? Alternatively does it mean that t= hey are just wandering around locally for food in groups, but are not =91in= tending=92 to migrate at all? Generally, are there a lot of species that migrate silently that you would = obviously miss recording? Perhaps the ratio of flight calls to radar image= s at the same site would be instructive, if possible to make these and if t= hey can be quantified usefully (for instance, do the radar images cover mor= e spatial volume than the acoustic recordings reach, and if so could you co= mpensate for the difference)? Presumably the flight calls are thought of as a coordination process to pro= mote keeping that species group bunched together to collectively improve na= vigation, or are there some other benefits?=97 calling while migrating must= have an additional otherwise unwanted metabolic cost. Steve On Oct 24, 2016, at 2:12 PM, John Kearney <john.kearney@ns.sympatico.ca<mai= lto:john.kearney@ns.sympatico.ca>> wrote: Hi All, Nocturnal migration was down to 88 flight calls at Carleton, Yarmouth Count= y, this week. The estimated minimum number of individual migrants was 78. T= he most common species was White-throated Sparrow (23 calls) and Yellow-rum= ped Warbler (11). Sparrows accounted for 63% of all calls, warblers for 25%= , and Kinglets for 7%. Straggling warblers included a Black-throated Green = Warbler and a Black-throated Blue Warbler. The weather radar in Caribou, Maine, indicated a similar low volume of migr= atory activity based on the density of echoes in clear-air mode. A summary table is given below and tables and charts can be seen here<http:= //www.johnfkearney.com/Carleton_YarmouthCounty_2016.html>. Estimated Call Minimum Species Count Individuals* White-throated Sparrow 23 14 Unidentified Sparrow 11 11 Yellow-rumped Warbler 11 11 Savannah Sparrow 9 8 Song Sparrow 7 11 Golden-crowned Kinglet 6 3 Unidentified Songbird 5 5 Palm Warbler 5 5 Blackpoll Warbler 3 3 Lincoln's/Swamp Sparrow 3 3 Dark-eyed Junco 2 1 Black-throated Blue Warbler 1 1 Black-throated Green Warbler 1 1 Unidentified Warbler 1 1 Total 88 78 * Calls that are more than one minute apart plus calls that are less than o= ne minute apart divided by three and rounded up to nearest whole number --_000_C8D7A39694DA4A70826A75980A89B229dalca_ Content-Type: text/html; charset="Windows-1252" Content-ID: <50D0C8CE846E7D42B5DA68F8DDA040EC@namprd03.prod.outlook.com> Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3DWindows-1= 252"> </head> <body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-lin= e-break: after-white-space;"> Hi John, <div>I=92ve seen a couple of groups of ~20-30 Am Goldfinches passing throug= h our yard in Halifax recently, feeding high in the trees plus visiting fee= ders, twittering away, then moving on after a half hour or less. I ha= d assumed that these were migrating groups en route, but this species never seems to figure in your flight call lists= . </div> <div>Does this mean that they really are in the business of migrating now b= ut do so silently so you miss recording them? Alternatively does it m= ean that they are just wandering around locally for food in groups, but are= not =91intending=92 to migrate at all?</div> <div><br> </div> <div>Generally, are there a lot of species that migrate silently that you w= ould obviously miss recording? Perhaps the ratio of flight calls to r= adar images at the same site would be instructive, if possible to make thes= e and if they can be quantified usefully (for instance, do the radar images cover more spatial volume than the acou= stic recordings reach, and if so could you compensate for the difference)?&= nbsp;</div> <div><br> </div> <div>Presumably the flight calls are thought of as a coordination process t= o promote keeping that species group bunched together to collectively impro= ve navigation, or are there some other benefits?=97 calling while migrating= must have an additional otherwise unwanted metabolic cost. </div> <div>Steve </div> <div><br> <div> <div>On Oct 24, 2016, at 2:12 PM, John Kearney <<a href=3D"mailto:john.k= earney@ns.sympatico.ca">john.kearney@ns.sympatico.ca</a>> wrote:</div> <br class=3D"Apple-interchange-newline"> <blockquote type=3D"cite"> <div lang=3D"EN-CA" link=3D"blue" vlink=3D"purple" style=3D"font-family: He= lvetica; font-size: 12px; font-style: normal; font-variant: normal; font-we= ight: normal; letter-spacing: normal; line-height: normal; orphans: auto; t= ext-align: start; text-indent: 0px; text-transform: none; white-space: norm= al; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"> <div class=3D"WordSection1" style=3D"page: WordSection1;"> <p class=3D"MsoNormal" style=3D"margin: 0cm 0cm 8pt; line-height: 15px; fon= t-size: 11pt; font-family: Calibri, sans-serif;"> <span style=3D"font-size: 12pt; line-height: 16px; font-family: 'Book Antiq= ua', serif;">Hi All,<o:p></o:p></span></p> <p class=3D"MsoNormal" style=3D"margin: 0cm 0cm 8pt; line-height: 15px; fon= t-size: 11pt; font-family: Calibri, sans-serif;"> <span style=3D"font-size: 12pt; line-height: 16px; font-family: 'Book Antiq= ua', serif;">Nocturnal migration was down to 88 flight calls at Carleton, Y= armouth County, this week. The estimated minimum number of individual migra= nts was 78. The most common species was White-throated Sparrow (23 calls) and Yellow-rumped Warbler (11). Spar= rows accounted for 63% of all calls, warblers for 25%, and Kinglets for