Migration Summary August 18th- 31st, 2017
Common Nighthawk. Photo by Sumiko Onishi
Fish Point was quiet for the first few days of fall banding owing to contrary winds and some inclement weather. A few season’s firsts showed up, including some Blackburnian Warblers and American Redstarts, but the fall migration didn’t really get underway until August 23rd, when northwest winds brought in a total of seven warbler species. That number increased steadily until August 25th, when it reached a high of 16 species of warblers and 7 flycatcher species. Wilson’s Warbler, Myrtle Warbler, Black-throated Green Warbler and Nashville Warbler were all new for the season. The banding totals were also high, with 33 birds banded. The following day was also quite active, but then the winds shifted around to the east and then the south, and fewer birds were seen.
One exception to this trend of decreasing activity was the number of Purple Martins seen. In spite of the south winds, Sumiko counted 143 of them flying over Fish Point on August 28th. They appeared to be migrating (flying in a straight line rather than circling as they would have done had they been feeding), and 247 Purple Martins were counted on August 29th. They are not the only aerial insectivore on the move this month: fifty Barn Swallows were counted over Fox Pond on August 22nd, and a Common Nighthawk showed up on August 25th, perched discreetly on a tree branch overhanging one of the net lanes at the banding station.
The presence of pin-feathered young birds was a sign that at least some of Fish Point’s local nesting birds successfully raised young this year. Three Red-bellied Woodpeckers were seen on August 18th, including one grey, scruffy-looking one that appeared to be a young-of-the-year bird. Five fledgling Carolina Wrens have been banded since August 20th, including one that was recaptured on the 27th. And PIBO has banded four young Eastern Screech Owls so far this season, all of them very belligerent and smelly. Three of them were captured together on the first net run of the morning of August 25th, and probably belonged to the same nest. Adults had been heard calling near the banding station in the spring, and it seems likely that at least one pair had a nest in or near Fish Point. A family group of Indigo Buntings was still present on Fish Point on August 21st, with two adult birds escorting one fledgling.
During the fall migration, PIBO staff make an effort to count the number of monarch butterflies they see during the daily census. While the daily totals are a mere fraction of what they were several years ago, when ‘roosts’ of hundreds of monarchs could be seen on the island, a handful still pass through the island on their migration south to Mexico. Nine monarchs were seen on August 28th, and eight were seen on August 29th.
On August 31st, the wind had begun to shift to the north again. Updates from banding stations to the north of us suggest that this year’s fall migration is about a week later than usual, but very busy. We’ll keep our nets open, and wait to see what September has in store!