A Bullock’s oriole eats on an orange near Rexburg. | Bill Schiess, EastIdaho.com REXBURG — With the temperature hovering around 30 degrees Tuesday morning, I did not expect to be entertained by the whistling song of a Bullock’s oriole, the first of the season. It was perched high in a hybrid poplar tree, flittering from branch to branch, apparently looking for something to eat — or it may have been moving just to stay warm. The week before, I ha…