This past Wednesday, October 15, I was outside in downtown Jamestown, New York, for much of the night. An area of low pressure had moved by earlier in the day and precipitation had cleared. Clouds were thinning and moving east. There are plenty of unnatural noises to hear on a typical night in the City of Jamestown – music, people shouting, vehicles and often large trucks passing by. There was also an incessant yet subtle chorus of noises coming from the low levels of the sky in the form of avian flight calls! Birds were moving south and in strong numbers with almost endless peeps and chips whispering through the turbulent skies.
I took some screen grabs that night to serve as a visual explanation.
Thrushes, sparrows and late warblers were migrating in a corridor through Chautauqua County being bounded by the low that had moved through and Lake Erie and another low to the west. Here is an infrared look showing the clouds having created that path.
The line was rapidly advancing east and providing just enough of a hole for the birds to slip through without being impacted by the second low to the west. Bearing in mind that low pressures spin counter-clockwise this area was producing a southerly flow so even areas as close as Ohio had uncooperative flight conditions. Remember that radar systems can be used to find birds but that night the Buffalo station showed a more complex tale.
You can see the rain coming up from the south across the eastern Mid-Atlantic getting into New England with more circling the low to the west. If you look at Buffalo you can see migrant birds being picked up on radar. However, that ring or circle does not appear very large, does it? It is also mostly blue showing “light” migration. This is because most of the heavy migratory movement was taking place at low altitudes with birds flying under the radar returns which gain elevation further from the radar origin. It made perfect sense to me as it backed up what I was observing outside.
I know one thing…I need to learn more nocturnal flight calls!
Scott Kruitbosch
Conservation & Outreach Coordinator
