March 3, 2010
Dr. David Aborn

Dear Students:
It's snowing here in Chattanooga, so it is hard to believe spring is almost here! I heard the first robins singing here on February 19th, and the bluebirds have paired up and are busily checking out nest sites. Best of all, it won't be long before migrants start arriving from their wintering grounds in the tropics! There are still a few weeks before things really get busy, so you have time to practice predicting migratory activity from looking at a weather map. Last week, Journey North was kind enough to post my tutorial on how to read a weather map and how weather affects bird migration.

What to Expect This Week
Does This Week’s Weather Mean for Migration? Let's take a look at the weather map:

  • Right now, much of the southern US is covered by rain and snow. If any birds were arriving from the tropics today they would be forced to land quickly along the Gulf coast because of the poor flying conditions, an event known as a fallout because the birds look like they are falling out of the sky. That means bird watchers and researchers would have plenty of birds to see.
  • Once the low-pressure area moves off the east coast, there is high pressure behind it, which means northerly winds. Those headwinds would keep birds grounded for an extra day or two. Once the high pressure moves east, winds will shift to the south and the birds can make their way north with the help of tailwinds.
  • Another storm system is moving in off of the Pacific Ocean. That means western migrants arriving from Mexico will be in the same position as birds in the East...grounded. In a couple of days, conditions will improve and then the birds will be able to move north.

Watch For Early Migrants!
IIt is still too early for large numbers of migrants to be arriving, but a few early arrivals are starting to trickle in. I have received reports of Tree Swallows and Purple Martins from Mississippi and Florida. In addition to swallows and martins, other early arriving species to look for include Ruby-throated Hummingbirds, Louisiana Waterthrushes, and Black-and-white Warblers.

While migration may be slow for now, it won't be long before we are all up to our necks in migrants, so dust off your binoculars!

Take Care.

David Aborn
North Chickamauga Creek Conservancy
Chattanooga, TN