March 17, 2010
Dr. David Aborn

Dear Students:

Birds are still trickling in. There are more and more reports of swallows, as well as some of the other early migrants. I know they are glad to see some good flying weather. That low-pressure area was very slow to move. The rain lingered over much of the eastern US for several days. If it had happened a few weeks from now, it would lead to some of the first big fallouts. But since it is still early, not many were forced to land. Once the system finally moved out over the weekend (with the exception of northern New England, where it is still raining), the skies cleared and the winds shifted. This allowed an influx of birds to arrive. Most birds that showed up were martins and swallows, but there were a few new species as well. The Gulf Coast had the greatest diversity, with the first Black-throated-green Warbler and Black-and-white Warbler showing up in Texas, the first Northern Parula in Mississippi, and the first Louisiana Waterthrush, Hooded Warbler, Yellow-throated Warbler, and Prothonotary warbler in Alabama.

Yellow-throated Warblers and Ruby-throated Hummingbirds have also started showing up in Georgia and North Carolina. The southerly winds have also helped push a couple of swallows farther north over the last day or so, with a single Tree Swallow arriving in Illinois and a Barn Swallow showing up in Maryland.

Migration is also starting to pick up out West. The improved weather has allowed 4 different swallow species (Tree, Violet-green, Northern Rough-winged, and Cliff) to make it to New Mexico, and the first Black-chinned Hummingbirds arrived in Arizona. It is nice to learn that more people are able to enjoy spring migration!

What Does This Week’s Weather Mean for Migration?
So will all of this continue? Look at the weather map and see:

  • There is a low-pressure area in the southwestern US. It is not a particularly strong system, but it is still bringing some rain to the area. That will keep migrants grounded for a day or two.
  • There is high pressure behind that system, but it is pretty far north. This early in the season, it probably won't affect the birds, as they are far to the south. Therefore, I would expect that by the end of the week the eastern US should see a new influx of migrants coming in from the tropics, and those that are already here should make some progress north.
  • Farther west, there is another front bringing rain to the Southwest. That will keep a lot of birds from coming up through Mexico. In another day or two, however, people should definitely keep an eye out for new arrivals! That second front will move across the country right behind the first.

As I keep telling you, migration will only be getter better and better for a while, so practice your weather map reading and look for those birds!

David Aborn
North Chickamauga Creek Conservancy
Chattanooga, TN