The march northward continues! For almost a week now, southerly winds have prevailed, allowing the migrants that have been here to reach a lot of the northern states, and allowing the late-season migrants to arrive from the tropics.

Numbers and Diversity in the North
Throughout the southern US, migration this week has been dominated by Tennessee Warblers, Blackpoll Warblers, and thrushes. At my study site, I have been catching and banding lots of Swainson’s Thrushes, Gray-cheeked Thrushes, and Veerys, and there are a lot of Tennessee’s and Blackpolls singing. I also caught my first Magnolia Warbler of the spring. The real numbers and diversity, however, have been coming from places much farther north. In Vermont and New Hampshire, birders have been seeing their first Ruby-throated Hummingbirds, Scarlet Tanagers, Least Flycatchers, Magnolia Warblers, Black-and-white Warblers, Prairie Warblers, and Black-throated-green Warblers. Up in Maine, Canada Warblers, Common Yellowthroats, Ovenbirds, and Red-eyed Vireos have also arrived.

Midwest Arrivals
In the Midwest, there were a lot of arrivals in Michigan and Minnesota. Birders in those states were treated to Orchard and Baltimore Orioles, Rose-breasted Grosbeaks, Yellow warblers, Blue-winged warblers, Orange-crowned Warblers, Veerys, Gray-cheeked Thrushes, and Indigo Buntings! Warbling Vireos and Nashville Warblers also made their first appearance in Indiana, and one birder in Iowa had 17 Baltimore Orioles at his feeder at one time!

The West: Migrants Welcomed From California to Alaska
You needed to go northward in the West to find a lot of migratory activity, although there was an influx of Western Tanagers in central California. The southerly winds pushed large numbers of Yellow-rumped Warblers into Washington, while Orange-crowned Warblers and Swainson’s Thrushes showed up in Montana. It was birders in Idaho, however, that had the best show. Reports from all over the state included lots of Yellow Warblers being seen, along with Nashville and Orange-crowned Warblers, Cassin’s and Warbling Vireos, Western Kingbirds, Lazuli Buntings, and Bullock’s Orioles. Even Alaska saw more migrants arriving, with Yellow-rumped, Orange-crowned, and Yellow warblers, Hammond’s Flycatchers, and Swainson’s Thrushes all being seen. That is a LONG way to fly from the tropics!

• For the next few days, people in the northern US should continue to see a lot of arrivals. But what is that I see in the northern Rockies? A cold front! In the Northwest and Rockies, the northerly winds will keep birds from making any progress for the next couple of days, so I hope they like it where they are!

• As the front moves eastward, the door will be closed on migration in the eastern half of the country. Temperatures in the southern US have been near 90 all week, but are expected to drop into the low 80’s by the weekend, and rain is forecast. Those are definitely not good flying conditions, so migrants will be force to land for a few days.

• By the middle of next week, the rain will have moved out and winds will shift back to the south, allowing migrants to reach their final destination and begin breeding.

Just because my reports will have stopped doesn’t mean you should put away your binoculars! You can use your skills to predict migration in the fall. Just as migrants want tailwinds to help them during spring migration, they want them during fall migration as well. Therefore, you get a lot of birds moving immediately after a cold front has passed. Those same north winds that are forcing them to land now are going to help speed them along in the fall!

International Migratory Bird Day: "Why Birds Matter"
This coming Saturday, May 10, is International Migratory Bird Day—a time when people all over the world can learn about birds and bird migration. This year’s theme is “Why Birds Matter.. Birds provide many benefits to people. Some species pollinate plants, others are important for dispersing seeds, while others are important in controlling pest populations. Birds can be found throughout art and literature, and many countries have images of birds on their money. There are many events happening all over the country to celebrate International Migratory Bird Day, and I am sure there is something going on in your area!

I hope you have learned from my reports. Feel free to contact me if you have any questions, and have a great summer!

David Aborn
North Chickamauga Creek Conservancy
Chattanooga, TN