The viral video of a 73-year-old man who says he got boarded up inside his low-income apartment is sparking an investigation.

Four men who have been stealing catalytic converters, some in multiple states, were arrested in Michigan, police said.

Anyone who has seen Christopher Clark or knows of his whereabouts is asked to contact the Detroit Police Department at 313-596-1240 or Crime Stoppers at 800-Speak-Up.

The unusually high-pitched songs may help the birds woo above background noises in their windy, mountain environment. (Paolo David Escobar/Neoselva Photography via AP)WASHINGTON Perched on a flowering shrub on a windy Andean mountainside, the tiny Ecuadorian Hillstar hummingbird chirps songs of seduction that only another bird of its kind can hear. For the new study, scientists climbed into the Ecuadorian Andes to reach high grasslands called paramos and locate the Hillstars breeding grounds. Humans can hear pitches up to about 20 kilohertz, but lose sensitivity to high-pitch sounds with age. During fieldwork, the younger scientists could usually hear the Hillstar hummingbird songs, but the older participants couldnt, Duque said.