Re: [nfc-l] Western radar?

[Jeffrey Buler]

Jesse, The NEXRAD network of radars are similar in design and therefore detect birds similarly. The radars out west have much more limited views of migration because the topography leads to partial or complete blockage of the radar beam or the radars are sited at high elevations so the beam is too high to detect migrating birds. So your suspicion of poor radar effectiveness is the major culprit. Some of the eastern radars have similar issues (e.g., Burlington Vermont radar comes to mind) but luckily the Appalachian mountains are a lot older (smoother topography) than the Rockies and don't block radar beams quite as much. However, there are also fewer birds migrating through the Rockies - though I don't know of a study that has really tried to quantify this in a rigorous way. Less biomass leads to lower radar reflectivity. So the migrations through the Rockies appear less dramatic in relation to the eastern US. Best, Jeff On 9/10/2013 12:19 PM, Jesse Ellis wrote: I know I've asked this of various folks before, and probably gotten reasonable if short answers, but I'm blanking out on the reasons. Can anyone shed light on why radar doesn't really work for detecting night flights in the intermountain West and the West Coast, esp. south? Is it literally that the birds are more spread out or fewer (seems very unlikely to me) or that all those boreal migrants trend east and clump up (seems possible, but shouldn't eliminate all flights) or that something about the topography/geography leads to differences in the effectiveness of radar? I am currently in the Los Angeles Basin, and I realize I'll probably not hear flights like I have out east, just because of migration routes, but I'm still curious about the radar question here. Are there any published or posted resources on this? Thanks, Jesse -- Jesse Ellis Post-doctoral Researcher Dept. of Integrative and Comparative Biology, UCLA -- NFC-L List Info: Welcome and Basics Rules and Information Subscribe, Configuration and Leave Archives: The Mail Archive Surfbirds BirdingOnThe.Net Please submit your observations to eBird! -- -- Jeffrey Buler, Ph.D. Assistant Professor of Wildlife Ecology Department of Entomology & Wildlife Ecology University of Delaware 246 Townsend Hall Newark, DE, USA 19716 Office: 302-831-1306 Mobile: 302-723-0156 Center for Managed Ecosystems -- NFC-L List Info: Welcome and Basics Rules and Information Subscribe, Configuration and Leave Archives: The Mail Archive Surfbirds BirdingOnThe.Net Please submit your observations to eBird! --