Work crews in the area discovered decapitated birds and called police. Officers responded along with an Animal Control officer who says she's seen this before.
"It's a ritual slaughter of some kind. We have decapitated birds, candles, fabric with markings on. It's a ritual of some description," San Francisco Animal Control Officer Elli Sadler told ABC7 News.
Animal Control officers say the birds are chukar partridges, game birds sold for food.
Officers say they pick up similar ritual remains all around the city about 20 times a year. They say there's no pattern to the rituals and say they've never tracked down anyone connected to them.