Purple Martin Roost Rings on Doppler Radar

Pretty cool sight the past few morning on the Doppler radar as thousands of purple martins take flight from their overnight roosts. These birds gather in the thousands in certain locations to roost for the night. Then each morning for a few weeks in the summer they all take off to forage for food around sunrise. These flocks are so large that they show up on Doppler radar as rings. These rings start small then get larger until the birds have spread out and the ring disappears.

These flocks of Purple Martins will be around June-August before migrating to South America in early September.The purple martins around Lake Murray, SC near Columbia are well known around these parts. Here’s 3 radar grabs from this morning.

From the Lake Murray, SC Homepage

North America’s first officially designated Purple Martin sanctuary is at Lake Murray! It’s also one of the largest roosting sites in America. Late each afternoon from June through late August or early September, hundreds of thousands of purple martins make their way to 12 acre Doolittle Island in Lake Murray (also called either Lunch Island or Bomb Island) to nest for the night. The number has been placed in the range of 750,000 purple martins returning to roost each late afternoon. Is is believed that the Lake Murray purple martin roost is the largest in North America (and possibly the world).




Here’s a loop from the entire southeast. You will see lots of ground clutter but look close and you’ll see just how many roost rings there are.


Lake Murray, SC Purple Martins( Credit the Lake Murray Homepage)