If you want to get a glimpse of the migration of the majestic tundra swans, you may not have to travel to Thedford.

Tundra Swans breed in the remote arctic of Canada and then winter in Chesapeake Bay where they feed almost exclusively on clams that they dislodge from the mud. The swans are the highlight of late winter in Lambton County.

Thousands of the bird land at the Thedford Bog, bringing tourists from miles around to get a look at the large birds.

Friday, a large flock in the hundreds made a stop on agricultural land between Oil Heritage Line and First Ave in Petrolia. The birds can be seen with the naked eye or a good pair of binoculors or camera lens but have settled in a protected area for a rest before moving north.

Here’s a few interesting facts about tundra swans from the Cornell School of Ornithology

• Lewis and Clark provided the first written description of the Tundra Swan during their expedition to the West, where the birds’ whistle-like calls prompted Meriwether Lewis to dub them “whistling swans.”
• The whistling swan, the American race of the Tundra Swan, currently is considered the same species as the Eurasian race, the Bewick’s swan. They were considered separate species in the past, distinguished by the large yellow patches on the face of the Bewick’s swan.
• The Tundra Swan stays in flocks except when on a breeding territory. Although most swans spread out to breed, a large proportion of the population on the breeding grounds still can be found in flocks. These swans are not breeding, and may be young birds that have not yet bred, adult pairs whose breeding attempts failed, or adults that bred in the past but for some reason do not in that year.
• During the breeding season the Tundra Swan sleeps almost entirely on land, but in the winter it sleeps more often on water.
• Tundra Swans breed in the remote arctic of North America. Parents defend their nests and young against a host of predators including foxes, weasels, wolves, and bears, as well as birds such as Glaucous Gulls, Common Ravens, Parasitic Jaegers, Pomarine Jaegers, and Golden Eagles. If the parents are present, they are able to defend the nest and nestlings from these threats. Wolves, people, and bears, however, are too big to fight, and most incubating swans leave their nests while these large predators are far away. By leaving quickly when large predators approach, the parents may make the nest harder to find.
• Tundra Swans wintering in Chesapeake Bay feed almost exclusively on clams that they dislodge from the mud. But it can be challenging to enjoy a peaceful meal: often the swan has to fend off a Ring-billed, Herring, or Greater Black-backed gull that swoops in to grab a clam from the swan’s bill – a successful tactic in about half of these “kleptoparasitic” encounters.
• Swans have long been associated with ideals of romance. Added to their elegant outlines and all-white plumage is their tendency to form permanent pair bonds by the time they’re 2-3 years old. Once a pair forms, Tundra Swans feed and roost together year-round.
• Based on banding records, the oldest known Tundra Swan was a female and at least 23 years, 7 months old when she was identified by her band in the wild, in Ohio. She was originally banded in the same state.