I looked out the kitchen window a few days ago and discovered the White-throated Sparrows had returned for the winter. These sweet little birds spend the summer from northern New England up through Canada. I would be willing to bet that the flock which just returned to my backyard is the same one that left here in the spring. Our flock of ten or fifteen birds like the brushy habitat on the edge of the woods behind our house.
Birds that migrate are much more site specific than we probably realize. There is no reason to carve out a new territory when they have found a location that meets all their needs. Unless that habitat has been destroyed through a natural disaster or a parking lot.
Like the Joni Mitchell song, Big Yellow Taxi:
Don't it always seem to go
That you don't know what you've got
Till it's gone
They paved paradise
And put up a parking lot
What struck me the other day was how happy those little birds seemed to be to return to our backyard with the feeder that always has seed and a bird bath with water to drink and bathe in. Anyone who has travelled for a few days and returns home knows how they felt to be back in familiar surroundings with their own bed and their own pillow and snacks in the fridge.
Whether birds can display emotions like happiness is probably best left to a discussion on another day but, I tell you, those birds looked for all the world like they were just happy to be home.