I've been getting a lot of questions about all the robins around Boise. So, I went to Idaho Fish and Game and here's an explanation:
A lot of people don’t realize that robins can be found year around in Boise.
The robins that breed here in the summer probably move south, and the north Idaho and Canada robins probably come here for the winter, said Rex Sallabanks, wildlife diversity program manager for Idaho Fish and Game.
Robins also change their feeding habits in winter. Instead of feasting on insects, they switch to berries. They go crazy for the Russian olive berries in our neighborhood.
The reason you suddenly see a large flock all at once is that they change from solitary feeders to flock feeders in winter, Sallabanks said. They will travel around in large flocks and eat fruit off a tree until it is gone and then move on, he said.
Sallabanks suspects that this cold snap has also brought in robins that live in foothills and forests to town for a better food supply. Up there, they eat juniper berries and the cold weather brought them down to find other fruit trees.
“They are fat looking probably because their feathers are puffed out to keep warm (much like down jackets make us look fat),” he said. The more air they can keep between their bodies and the outside feather layer, the better they warm up that air, keeping them warm.
Technically, they are probably a little leaner this time of year because keeping warm uses a lot of energy and fruit has very little protein content, he said.
Photo by Pete Zimowsky/Idaho Statesman
So, instead of robins being a sign of spring, maybe they are a sign of winter.