Hi everyone, I've been lurking and enjoying reading the posts so far ... much as I'm intrigued by all the possibilities for nocturnal observations, for the fall I'm primarily preoccupied with being up at dawn to do migration monitoring via mist-netting (at McGill Bird Observatory in Montreal, Quebec). As an aside, we happen to have an Environment Canada radar station within 1 km of our site, but as was noted the other day, the images released to the public aren't useful for tracking migration - if anybody does find a way around that, we'd be most interested.
Regarding the direction of flight paths, I have a couple of comments. A couple of years ago I had an opportunity to take a portable radar unit into the foothills of northeastern British Columbia (approx 1800 - 2000 m / 5500 - 6000 ft elevation). I operated it for a few hours after dusk in three different locations to get an idea of how migrants were moving (both direction and height). While topography would certainly be expected to have an effect in a landscape with stark ridges and valleys, I was still surprised at just how varied the movements were ... even in early September, there were nearly as many heading straight north as south (let alone most other directions). The other note is that analysis of banding data suggests that for a lot of species, the notion of "traditional" north-south migration may not be all that accurate. In fact, the Canadian Atlas of Bird Banding (http://www.cws-scf.ec.gc.ca/publications/BBA-AOB/v1ed2/index_e.cfm) shows quite a strong northwest-southeast axis of movement for many species across much of the continent (and skewing toward northeast-southwest in the far east). This is shown particularly well by Common Redpoll (http://www.cws-scf.ec.gc.ca/publications/BBA-AOB/v1ed2/ShowBird.cfm?lang=e&; aou=5280), though admittedly it isn't a typical migrant. Still, the pattern isn't all that different for others I randomly picked to look at, such as Yellow-rumped Warbler (http://www.cws-scf.ec.gc.ca/publications/BBA-AOB/v1ed2/ShowBird.cfm?lang=e&; aou=6550) and Swainson's Thrush (http://www.cws-scf.ec.gc.ca/publications/BBA-AOB/v1ed2/ShowBird.cfm?lang=e&; aou=7580). For many other species there aren't enough recoveries mapped to describe any clear pattern, but it still looks like truly north-south movements are far from typical. How this translates on a local level I'm not sure - I expect we have much yet to learn (a common sentiment it seems). But I wouldn't be surprised if in some cases different species (or even different populations of the same species) moving through the same area might be heading in somewhat different directions. Happy observing, Marcel Gahbauer Executive Director The Migration Research Foundation Montreal QC www.migrationresearch.org mar...@migrationresearch.org -- NFC-L List Info: http://www.NortheastBirding.com/NFC_WELCOME http://www.NortheastBirding.com/NFC_RULES http://www.mail-archive.com/nfc-l@cornell.edu/maillist.html --
