Continental Migration Project

Last night's radar image from central Pennsylvania - NEXRAD KCCX

The continental migration project explores the complex interactions of long-range bird migration with weather and terrain. The National Weather Service's NEXRAD weather radar network allows real-time monitoring of migration and the analysis of its interaction with terrain and weather. Because of the importance of tailwinds for most migrating species and updrafts for soaring species, insights gained from the analysis of NEXRAD observations allows migration forecasting with lead times up to several days.

I have written a program for the automated detection of bird echoes in these National Weather Service NEXRAD radar images. The program is experimental and subject to change as I learn more about bird echo characteristics. The program attempts to distinguish birds from precipitation but is by no means perfect. While it works most of the time for Central Pennsylvania its bird echo recognition algorithm is easily confused in coastal regions. Likewise, if it thinks both birds and precipitation are contributing to the echoes, it makes no attempt to separate the two. Instead it reports that it could find no birds (setting bird echo intensity equal to 0 dbz). Occasionally, especially during shallow snow events, it will mistake a broad area of precipitation centered on the radar site for birds, otherwise it does a good job of rejecting radar images that include precipitation echoes. To see the current plot of this season's experimental radar-derived migration records for Central Pennsylvania, click the "Summary of Season" item in the menu below.

I have also developed a neural net artificial inteligence system to forecast migration intensity. To see the current migration forecast for Central Pennsylvania, click the "Current Migration Forecast" item in the menu below.

Current Migration Forecast | Explanatory Examples | Other Radar Ornithology sites | Summary of Season

Explanatory Examples

• Bird echo in "clear air mode"
  • Broad area of echo centered on the radar site
  • Echo strongest near the radar site
  • Echo speckled at the finest scales
• Bird echo in "precipitation mode"
  • Different color scale for echo intensity
  • Weaker bird echoes are lost
• Thunderstorm echoes
  • Echoes scattered and patchy with much variability on the scale of counties
  • Echoes not, however, speckled at the finest scales
• Steady rain echoes
  • Echoes more widespread and less patchy
  • But variability is still on the scale of counties instead of fine-scale speckling
• Shallow snow echoes
  • Echoes centered on radar just as with birds
  • But echoes are mottled rather than speckled - i.e. the variations are of a size scale similar to a township instead of on the much smaller pixel scale
• Birds reacting to lake-driven weather

Selected Links

• Clemson University Radar Ornithology Lab

• Cornell University Birdcast

• Frank S. Pearce