[CT Birds] Using radar to monitor nocturnal migration

Nick Bonomo nbonomo at gmail.com
Sun Apr 22 21:17:29 EDT 2007

Hi all,

I wanted to bring this site to the attention of CTBirders:

The webmaster of this site (David La Pluma) uses radar images to
monitor nocturnal migration, and you can do it yourself!

I'm not going to get into details because I'm still learning the
basics of radar interpretation, but the jist of it is pretty simple.
One can use certain radar feeds to "see" birds liftoff at dusk and
continue to migrate through the night. This is very cool stuff. The
density of migrants can be read with a simple legend, like with rain.
Of course precipitation also shows up on the radar, so you need to
learn how to recognize birds versus rain. That part is usually easy,
since rain forms in bands which move across a region and vary greatly
in intensity, while the bird migration usually occurs fairly evenly
over a broad front.

Anyway, check out that site for some great information!

This is the site I'm currently using to check the radar myself:

As an example, try this at the site I just listed:
 - under "Product", click Regional Reflectivity
 - under "Background", keep it at Black
 - keep "End Date" and "End Time" as is
 - change "Loop Duration" to whatever would take you an hour before
sunset (so if you do this at 10pm, set the loop to 3 or 4 hours)
 - Now just click on the state of Connecticut on the map, sit back,
and wait for the images to load

After the images load (this could take a few minutes), the radar loop
will run. Notice how the radar fills up with activity after sunset.
These are the birds. FYI, you need the Java plug-in to run the loop I

I just did this, and the early returns from tonight indicate a really
good migration tonight....heaviest activity yet this season, for sure.
Heavier than last night at this time. Not surprising given the warm
temps and light southwest winds straight from the southeast up to New
England! Tomorrow might be a good morning to get to those migrant
traps and find more early warblers, including an overshoot like
Prothonotary or Yellow-throated.

Back to the woodcreeper site at the top of this message: David lives
in New Jersey and bases his observations/predictions on that state.
But we are fairly close, so we often have similar migration events.
This is still a worthwhile site to monitor. I've learned a lot from it
already. During the peak of migration (now through May), David usually
posts radar loops the following morning. They are available in
thumbnails at the bottom of each daily posting. So, right now you
could watch last night's migration through New Jersey as another

Nick Bonomo
Orange, CT

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