What's a Whimbrel?

Nature Notes for May 27, 2011

“I know what a warbler is, but what’s a Whimbrel?” That was a query I fielded last weekend at Presqu’ile Provincial Park’s annual Warblers and Whimbrels weekend.

A Whimbrel is a large shorebird with a long downward curving beak. If they appear in Northumberland County, they usually come around May 24. Six birds appeared for a short time on the beach at Presqu’ile on Sunday, May 22.

They used to come so regularly to Willow Beach, a Lake Ontario shoreline beach west of Port Hope which is now largely eroded, that the local field naturalists club adopted it as their logo.

The old name for a Whimbrel was “Hudsonian Curlew”. Hence, the club’s newsletter is named The Curlew.

Like so many of the birds I write about, the Whimbrel has experienced a huge population decline. Studies done by the Center for Conservation Biology (CCB) at the College of William and Mary and The Nature Conservancy (TNC) recorded about a 50% decrease in Whimbrels counted in a staging area in the Delmarve Peninsula between studies done in the mid-1990s and 2008-2009.

Like many shorebirds, Whimbrel are known to nest in the high Arctic and winter in the south, some as far south as South America. Until very recently, it was thought that birds that staged in Delmarva (on the eastern seaboard of the U.S.) were the ones that bred around James Bay.

Recent studies have shown quite a different picture. In 2008, 2009 and 2010, several Whimbrels were fitted with satellite transmitters by researchers from CCB. One of these birds, named Hope, is the star of the project. She was given her Teflon harness and solar powered satellite transmitter in spring of 2009. She has completed two complete migrations and travelled, not to Hudson’s Bay as expected, but to the Mackenzie Delta in the Yukon.

Each winter, she has returned to the same wintering area at Great Pond, a Birdlife International Important Bird Area in St. Croix in the U.S. Virgin Islands. For the third consecutive spring, she has been found feeding at the same creek in Virginia, the same place where she was originally fitted with the transmitter.

This one bird has changed the accepted view of migration paths of Whimbrels. There is a substantial east-west direction to migration their migration paths, not just a north-south one.

Each place mentioned in the paragraphs above is vitally important to the survival of the species. Hope is not the only bird in the study and additional information about migration is being obtained from these other birds.

In addition to the satellite transmitters, some of the Whimbrels captured in Delmarva by the CCB team were fitted with radio transmitters. These require a receiver called a “datalogger” on the ground to record the passage of birds carrying the transmitters.

Since there are sight records of Whimbrel for the Lake Ontario shore, several of these were located here. One of these was financed by Willow Beach Field Naturalists and placed at Presqu’ile Provincial Park. Others were placed at Col. Sam Smith Park and Tommy Thompson Park in Toronto by the Toronto and Region Conservation Authority. In spring 2009, 10 of 30 tagged birds were detected at Col. Sam Smith Park.

None were detected in 2010, perhaps due to northeast winds during most of the spring migration period which pushed the migration path further west than usual.

Updated tracking maps and more information about this project can be found at http://www.ccb-wm.org/programs/migration/Whimbrel/whimbrel.htm

Let’s hope that this study can determine the cause of the Whimbrel’s decline before it is too late to reverse it.