September 4th: The Kind of Day Counters Dream About
Posted on in On the Mountain by David Barber, Senior Research Biologist
As I climbed the Express Trail to North Lookout on Friday, September 4th, the forest was already filled with the little chip notes of migrating warblers—always a promising sign for a good day to come.
There were lots of warblers moving through from the moment I reached the Lookout, predominantly Cape Mays, but also 13 other species, including an absolutely stunning male prairie warbler, which is an unusual migrant to see here. Yellow-throated vireos, least flycatchers, wood thrushes, indigo buntings, rose-breasted grosbeaks, and scarlet tanagers pushed past to round out the fantastic morning songbird flight. Little did I know the excitement was just beginning.
The light winds and rain from the previous 3-4 days had resulted in a poor show for migration, but conditions were looking up. The forecast had predicted northwest winds for the next two days and I had my fingers crossed for a good flight.
Soon enough the air warmed and the raptors began to appear, riding thermals up along the ridgeline. The first bird of the day was a merlin that came in close past the owl pole at around 6 AM. Broadwings, some sharpies, and ospreys began moving through soon after, many at eye level. It was the first good flight of ospreys in the season so far, which was encouraging to see. Bald eagles were moving through, maybe one or two every hour, which is nothing significant but also not unexpected for early September.
On the eleven o’clock hour, 7 bald eagles had passed through, and that number quickly jumped when 19 more were counted between one and two PM. Then 9, then 12, and within a four-hour time span we had 49 eagles, which was already a record-breaking number for a single day count. In the hour with 19 eagles counted, we actually had 8 balds circling in the same thermal, which is something I had never seen before. In November we may see groups of 2-3 in the same thermal, but nothing quite like that.
No one wanted to leave the Lookout that afternoon; everyone’s eyes were locked on the horizon as we took in the historic flight. I ended up heading down two hours later than usual, after the last two eagles passed low. The final birds of the day were two female northern harriers just before 7 PM.
We saw 217 total birds of 10 different species that day, including 28 ospreys, which was our best flight in a single day since 2020 and the best I had seen in the last 10 years. The total bald eagle tally by the day’s end was 64 eagles, completely smashing the old record of 48 that was set back in 1950. Going back in the records later, I realized that the previous record was also set on September 4th—shattered 76 years later to the day.
It really was the perfect storm. We were right in the middle of our early peak of bald eagle migration, but we hadn't had a decent flight yet. We also hadn't had a good cold front come through and the previous 3-4 days had been really poor migration weather. So, when we finally had the front move through with gusty northwest winds, the birds took advantage.
It was an epic day, the kind counters dream about, and one I won’t soon forget.
Photos taken by Abigail Junge at North Lookout on September 4th, 2026.