Ararat-based wildlife photographer Wayne Suffield visits the area regularly and said the bird life has gone quiet since the incidents occurred.

"There is quite a number of endangered birds that come through, so it's a very special place," he said.

"It's astonishing how quiet it's gone since those two nights. They have had a direct impact.

"Why is it that a small bunch of hoons think it reasonable to drive off the well marked tracks onto the drying swamp for destructive circle work?"

The swamp is at the northern side of Green Hill Lake.

"It's the only wetland we've got (in the Ararat region)," Mr Suffield said.

"It is a stopover point for several species of migratory wanderers returning from places as far away as Northern Siberia.

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"It is a breeding area, in good years, for brolgas, pelicans, swans, silver gulls, several species of cormorants, pied stilts, and pipits.

"Wedge-tailed Eagles have raised young along the lake border this season. It is a critical part of the local environment and is visited by an increasing numbers of birding tourists."

Green Hill Lake Development Board president Gwenda Allgood said the culprits had been caught on the lake's newly installed security cameras.

"There has been damage done to part of the lake by a few hoons and we're looking at the footage to see who they are," Mrs Allgood said.

"The area they are mucking up is the nesting area of the birds."

Mrs Allgood said behaviour at the lake across the Australia Day weekend was otherwise "spot on", with the lake proving a popular choice for campers.

"I counted 106 (campsites) on Saturday with more coming in," Mrs Allgood said.

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