Weather and Songbird Migration: March 15, 2017
By Dr. David Aborn

Winter returned with a vengeance!
Blue-gray gnatcatcher
Laura Erickson

Blue-headed vireo
Blue-headed vireo
Laura Erickson

Hooded oriole
Hooded oriole
Linda Tanner/CC BY-NC-ND 2.0

Weather Map
Weather Map
Ornithologist Dr. David Aborn  

Dear Journey North,

March Madness?
While we may have set our clocks forward this weekend, I think we apparently set the season backward! When the sports channels started talking about March Madness, I don't think this is what they had in mind! It is definitely more like January than March, and it will definitely affect bird migration.

Many Migrants, Many Places
Many of the early migrants started arriving in many places last week. Many of the various swallow species, Black-and-white-Warblers, Blue-gray Gnatcatchers, and Ruby-throated Hummingbirds showed up in Georgia, while in Texas, the first Yellow-throated Vireos, Northern Parulas, Purple Martins, and Ruby-throated Hummingbirds were seen. Here in Chattanooga, all the swallows have arrived, along with the first Blue-headed Vireo. Also, I just returned from taking my ornithology class (ornithology is the study of birds) down to the South Carolina coast for a few days, to see birds they might not see here, and we saw our first Blue-gray Gnatcatchers.

Out west, southerly winds helped bring in many new arrivals, including Bell's Vireos, Plumbeous Vireos, Lucy's Warblers, Rufus Hummingbirds, and Black-chinned Hummingbirds. In southern California, the first Hooded Oriole was seen, along with hundreds of Swainson's Hawks.

But Winter Wouldn't Let Go!
Then winter returned with a vengeance! The storms in the south and blizzards in the Midwest and east meant all those birds couldn't go anywhere. There are no reports of migrants north of the Carolinas in the east, Oklahoma in the Midwest, or Arizona in the west. If you look at the weather map, you can see that the cold front has moved off the east coast, taking the rain and snow with it, but there is a large area of high pressure bringing down lots of cold north winds to the eastern half of the country. Temperatures were near or below freezing all the way down to Florida (it was 24 here!). All those migrants need to just bundle up and stay put for a few days, because they have some strong headwinds.

Better Weather On the Way
In the western part of the country it is a different story. That high pressure area has moved far enough east that migrants now have a tail wind, which means the birds that are already here can continue their journey north, and new groups can start arriving from the tropics. They won't have very long, however. If you look at the map, there is another front coming in off of the Pacific, bringing rain to the northwest.

In the next couple of days, conditions in the east and west will reverse; the high pressure will have moved far enough east that the winds will shift to the south, making for good flying weather, while the west will be shut down by rain, snow, and north winds. Over the weekend, it will flip-flop again, with good weather in the west and poor weather in the east.

Things Will Pick Up As March Ends
As you can see, March can be very changeable. As we head toward the end of March migration will really start to pick up, so knowing how to interpret the weather patterns will help you predict where there might be a lot of birds! Take care,

  • David Aborn
    North Chickamauga Creek Conservancy
    Chattanooga, TN
Next Update: March 22, 2017