Residents in Littleton were alerted Friday morning after a black bear was observed near Spectacle Pond, police said. “A call went out to residents because it was during school bus time, and we felt it necessary to alert residents that there was a bear sighting in the area,” said Pamela Cvitkovich, an administrative assistant for the Littleton police. A couple residents called to report the bear about 7:30 a.m. Friday, according to a police dispatcher. The bear was seen walking across Great Road toward Spectacle Pond, the dispatcher said. He said he did not know the size of the bear.