Here's a different example of birds on radar: Broad-winged Hawks migrating in the daytime along the south shore of Lake Ontario.
Large birds such as raptors rely not just on favorable winds but also more on updrafts than on powered flight during migration. Updrafts in the form of thermals are a daytime phenomenon. Winds, which form updrafts where they strike mountain ranges, are also generally stronger in the day. Neither type of updraft forms over water, so the birds which rely on updrafts generally go around large bodies of water if they can. In these clips, enough raptors have accumulated against the shore of Lake Ontario and gathered together even more as the work their way east, and climbed high enough that they showed up on the radar. This is why we go to Derby Hill and Braddock Bay in spring.
--Dave Nutter
Begin forwarded message:
Begin forwarded message:
From: Tom Carrolan <[email protected]>
Date: April 17, 2012 6:46:04 PM
To: Dave Nutter <[email protected]>
Subject: RE: weather, radar, & migrationFYI... in daylight.
Begin forwarded message:
> From: Tom Carrolan <[email protected]>
> Date: April 17, 2012 12:44:07 PM EDT
> To: Bill Purcell <[email protected]>, Bill Evans <[email protected]>, Christopher Wood <[email protected]>
> Subject: BWs: 16 April 2012
>
> This link will last a week or so. I am going to capture animations of this event for YouTube viewing.
> ===
>
> Derby had 3K, while Braddock Bay had 37K for the day. Most of the day was S winds, angling toward SW into the afternoon -- not unfavorable for Derby Hill. This NEXRAD site is quick and dirty... okay ugly, but shows the birds.
>
> Here's the midday flightline and the initial 1000 bird-movement; this was detected at Derby Hill:
>
> http://vortex.plymouth.edu/gen_nids.cgi?ident=tyx&pl=n0r&yy=2012&mm=04&dd=16&hh=18&nn=00&size=912x684&loop=yes1&zoom=¢er=
>
> However, when we look at later into the afternoon (thru 4pDST), you can see the bulk of the flight leaving land at Nine Mile Pt, although not outlandishly pelagic. This crop of BWs was essentially undetected at Derby Hill:
>
> http://vortex.plymouth.edu/gen_nids.cgi?ident=tyx&pl=n0r&yy=2012&mm=04&dd=16&hh=20&nn=00&size=912x684&loop=yes1&zoom=¢er=
>
> Let me know if the links don't work for you (I can shorten w/tinyulr.com )
>
> Tom Carrolan
> Liverpool NY
> www.hawksaloft.com
> .....................................................
> The only fence against the world
> is a thorough knowledge of it.
> -- John Locke, philosopher (1632-1704)
> ....................................................
>
--
Cayugabirds-L List Info:
Archives:
Please submit your observations to eBird!
--
