Animal Control officials are urging residents on the west side of New Canaan to be alert after two coyote versus dog incidents this week, including one where a Chihuahua mix was taken. On Monday, a resident of Knapp Lane reported that a Labrador retriever sustained puncture wounds to the inside of a back thigh after two coyotes were sighted in his yard, according to Officer Allyson Halm, head of the New Canaan Police Department’s Animal Control section. On Thursday, a man on Adams Lane put his two dogs out in the yard while he went briefly to his garage and then heard a commotion, Halm said. He watched two large coyotes snatch his 13-pound white Chihuahua mixed-breed dog and run off through the woods, Halm said. The man chased but was unable to keep up with the coyotes, and believes his dog was already dead in the animal’s mouth, she said.