Weather and Songbird Migration: March 7, 2012
Dr. David Aborn, ornithologist
Dr. David Aborn

Dear Students:

Spring migration continues to pick up. I have seen or been told about hew migrant sightings from all over the country. Last week, I pointed out the strong cold front that would keep birds grounded for a few days. That storm system brought those terrible tornadoes to many places in the South and Midwest, and some pretty strong north winds followed it. Over the past couple of days, however, the high pressure system has moved east, and the winds have shifted to the south. This has allowed birds that were already here to start moving north again, and more birds have been arriving from the tropics.

New Species in the Central, South, and Eastern US
The swallows have been making progress, with many Tree Swallows arriving in Indiana and Washington, DC. People in Illinois saw their first Barn Swallows and Purple Martins of the year. In Texas, the Black-chinned Hummingbirds have arrived, as have the Golden-cheeked Warblers—a gorgeous bird that only breeds in central Texas. New species seen in Louisiana over the past couple of days include Yellow-throated Warblers, Yellow-throated Vireos, Northern Parula, and Blue-gray Gnatcatchers. Birders in Alabama have been treated to their first Ruby-throated Hummingbirds and Northern Parulas. I have not seen anything other than swallows here in Tennessee, but I know some of those species I just mentioned are not far away!

Migration in the West
Birders our West have also been enjoying their first taste of spring migration. People in Arizona have been seeing Ash-throated Flycatchers and Barn Swallows, while those in California have reported the first Rufus Hummingbirds, White-throated Swifts, Cliff Swallows, and Warbling Vireos.

What Can We Expect This Week?
So will this trend continue into next week? Let's see if the weather map gives us any clues:

  • A cold front is currently over the Rockies and the Southwest. It is not a strong front. There's not a lot of rain with it right now, and the winds behind it are not strong. That means birds in the western US might only be grounded for a day or so, and then they will be able to head north again. New birds can fly up from Mexico without too much trouble.
  • As the front moves east over the next couple of days, it will pick up moisture from the Gulf of Mexico; the southern and eastern US can expect more rain from the system, but still no strong north winds. That means birds will have poor flying conditions while the front is passing through, but once it clears, they should be able to take off and head north again.

Keep Practicing!
Migration will be in full swing before you know it, so keep practicing your weather skills and get out there to watch for those birds!

Take Care.

David Aborn
North Chickamauga Creek Conservancy
Chattanooga, TN