A bald eagle found dead near its nest in Arlington last month died from exposure to rat poison, officials said. It’s the fourth such death in Massachusetts, renewing calls for a statewide ban on the toxic chemicals. Wildlife officials said the female eagle, known as Fae, had multiple types of second-generation anticoagulant rodenticides, or SGARs, in its system. The toxins are commonly used in commercial rat bait and can be fatal to predators th…