Two varieties of gulls are passing through Lawrence from Canada and the northern states. Franklin’s Gulls, such as the smaller bird here, are black behind the head, and they have a gray mantle. The larger Ring-billed Gull, behind, is known for its black ring around the beak. The birds, after stopping at Clinton Lake on Wednesday, will head for warmer southern climates.

Stacy Snider estimated more than a thousand gulls had gathered last week on the grass at Sunflower School’s playground.

After she dropped off her children, Michael, 8, and Elizabeth, 7, at class, Snider ran home to get her camera and headed back to the school, 2521 Inverness Drive.

“It was amazing just seeing that many birds on that property,” Snider said.

Birders say area residents have a great opportunity right now to view large flocks of gulls and other birds during such a busy time in the migration season.

“There are new species that are showing up every day on the reservoirs and wetlands,” said Kylee Sharp, a Lawrence Virtual School biology teacher.

She said two main types of gulls have migrated from Canada and the northern Plains states and are headed farther south for the winter.

Franklin’s Gulls are black behind the head, and they have a gray mantle. Otherwise they are mostly white. The birds eat fish and tend to travel in large flocks.

“They will catch insects, too. Sometimes you will see them following tractors during harvesting,” Sharp said.

Wednesday on the shore at Clinton Lake, the larger Ring-billed Gulls — known for their black ring around the beak — were mixed in with some Franklin’s Gulls.

Sharp said it’s not uncommon for gull species to mix. Herring Gulls and Bonaparte’s Gulls also migrate through the area.

Marty Birrell, nature education supervisor at Prairie Park Nature Center, said as the leaves continue to fall from trees and many types of birds are migrating, this becomes a perfect time for birders.

“These birds are doing something that’s very high risk and uses a huge amount of energy,” Birrell said. “And the fact they can do it over and over again is truly remarkable.”