I wrote about the winter finch forecast a few weeks ago. The annual forecast predicts which and how many finches will irrupt into New England from the north each winter. An irruption occurs when birds that are not typically seen in an area appear, sometimes in great numbers, during the winter.

Food, of course, is the main driver of these irruptions. If the seeds of a bird species’ diet are scarce up north, the birds will come south to find a food source.