In June 2020, BirdWatching reported on the work of Debbie Leick and her colleagues recording and identifying nocturnal flight calls of migrating passerines through western Montana. Further data analysis has revealed a startling pattern of migration not just by passerines but also by Upland Sandpipers.
Leick and her boss, Kate Stone, both work for MPG Ranch. When they installed their first three microphones in 2013, they were astonished to identify a trio of Upland Sandpiper calls among their many other recordings that year. Eventually, they installed 50 listening devices throughout the Bitterroot Valley, and with more microphones, the number of Upland Sandpiper detections ballooned — to 29 in 2018 and a whopping 51 the following year.
The result is surprising given that Upland Sandpipers are almost unrecorded in Montana west of the Continental Divide, with a total of only five eBird records. What’s going on?
“We can’t say anything for sure,” Leick says, “but my hypothesis is that these birds are coming down from Alaska or nearby areas. They’re following some sort of migration corridor that we think a lot of other birds out of Alaska are taking.”
The dearth of eBird records could be explained by the fact that Upland Sandpipers are “extreme migrants,” often covering thousands of miles at a stretch without touching down. The numbers suggest, however, that Leick and Stone’s sandpipers are no strays that have gotten lost or blown off course. If anything, their results may be underrepresenting the actual number of Upland Sandpipers passing through since many of the birds could be flying too high for the microphones to detect. Either way, their research suggests a surprising, previously unknown migration pathway for Upland Sandpipers, one that broadens our understanding of these enigmatic grassland shorebirds.
This article appears in “Birding Briefs” in the July/August 2021 issue of BirdWatching magazine.