The birds are moving! Last week I showed you how to read a weather map and told you how weather can affect bird migration. I mentioned that strong north winds would keep any migrants grounded along the extreme southern part of the United States, and that is what happened. One thing I was not expecting was so many birds arriving over the past week!

Early Migrants Right on Schedule
Some of the typical early migrants showed up on schedule; Barn Swallows and Ruby-throated Hummingbirds were seen on the Alabama coast, Northern Parulas arrived in Florida, and a Purple Martin showed up here in Chattanooga. A little farther west, where winds shifted to the south over the weekend, a lot of species were showing up. Birders in Louisiana reported Ruby-throated Hummingbirds, Blue-headed Vireos, Blue-gray Gnatcatchers, and House Wrens. People in Texas have been treated to Tree, Barn, and Northern Rough-winged Swallows, gnatcatchers, parulas, and House Wrens, along with the first Black-and-white Warblers, White-eyed Vireos, Gray Catbirds, and a Wilson’s Warbler. Even farther west, in Arizona, Tree, Northern Rough-winged, and Violet-green Swallows arrived, along with a Yellow Warbler—which is one of the earliest arrivals there on record! In San Diego, CA, Warbling vireos, Wilsons Warblers, Northern Waterthrushes, Black-throated-gray Warblers, and an American Redstart showed up.

And we are only in the first week of March!

• Another front is moving across the country, but it is not as strong as the last one. It will bring some rain to the southern US tomorrow and Friday and some wintry weather to the Midwest and Northeast. That means many of the migrants I just mentioned will be stuck where they are for a few days.

• A second front is moving into the western US, which will bring more rain and very strong winds there and also grounding the migrants in the Southwest. Winds will shift back to the south across the country over the weekend, so birds will be able to resume their migration, and people in the southeast, mid-Atlantic, Great Plains may see some of their first migrants showing up. If the birds go much farther, they are in for a big surprise! Even if the wind are good and the skies are clear, birds will find much of their breeding area covered in snow and ice. In these situations, birds may actually move back SOUTH for a week or two and then go back north again. It is called reverse migration and it enables migrants to survive, rather than trying to find food that isn’t there yet! 

While I did not expect big numbers of birds to show up, I wasn’t expecting the diversity of species that arrived this week, so you never know what can happen! I will let you know if there were any more surprises in next week’s report.

Take care.

David Aborn
North Chickamauga Creek Conservancy
Chattanooga, TN