ÒÁÈ˾þÃ

Half a dozen new arrivals have set off a mass migration at San Francisco Zoo. The Magellanic penguins from Ohio were introduced to the zoo’s existing 46-strong colony in December. Since then, they have persuaded the colony to join them swimming in circles around a small pool all day, only to stagger out at dusk. Jane Tollini, the penguins’ mystified keeper, says the birds just used to sit in their burrows or spend time decorating them with palm fronds and pampas grass. “Before, it took a grenade to get them out,” she told the San Francisco Chronicle. Magellanic penguins…