A colony of the big birds has been ruffling the feathers of local farmers.
"There's about 150-200 of them now. They eat the grass and [defecate] all over the place.
"They're huge birds and it's incredible how much they [defecate]. It's like dog [faeces] everywhere. We all have problems with them," Taieri farmer Grant Love said yesterday.
"They usually come off the lake around August-September, but it's got worse in the last two years. If they just came for short periods of time, you could live with it. But when they come in March and hang around all winter eating the grass ..."
Mr Love recently advertised in the Otago Daily Times for shooters to control the population.
The black swan was introduced to New Zealand from Australia as an ornamental waterfowl in 1864.
Otago Fish and Game operations manager Ian Hadland said swans were counted every summer and there was a transient population of between 1500 and 2500.
"We cull about a 1000 a year and the population doesn't seem to go up or down. They're reasonably static. They usually cruise around between the coastal estuaries, but we had heard they were targeting pasture out there," Mr Hadland said yesterday.
"Either the lake weed in Waihola is in some sort of trouble, or they've suddenly decided they like high-nutrient grass more than the lake weed," he said.
Swan-shooting season runs until August 26, with a bag limit of five swans a day.
