This video from the USA says about itself:
23 April 2015
Male Bluebird on the Ball listening to other birds call, sing, and a Woodpecker pounding, chased by Doves, sliding off the ball and finally singing as a female sits in her new front yard nest nearby. FYV FrontYardVideo, Eastern Bluebird (Sialia sialis).
From Wild Birds Unlimited in the USA:
Monday, September 9, 2013
Where bluebirds winter
Do you know if bluebirds go somewhere in the late summer and fall? I believe this is when I stopped seeing them last year. Stephanie
That’s a good question. It’s very normal for Eastern Bluebirds to gather together in large flocks starting in August until September in search of food. After nesting season has ended, they usually form large nomadic groups that roost at night in the woods.
Their diet changes from mostly worms and insects to fruit, nuts and berries. They can eat crab apples, Mountain Ash tree berries, and sometimes look under feeders for nuts. They also appreciate open water in the winter. If you have a pond or heated birdbath they may show up in large numbers for afternoon drinks.
We often think of migration as birds traveling thousands of miles south to winter in a tropical climate. That’s true for some birds even some bluebirds. The bluebirds that nested in Canada may skip over Michigan to winter in the southern states, but in southern and mid-Michigan, many bluebirds are year-round residents. Scientists think it’s due to genetics whether they want to fly south or winter over. Some birds are compelled to move south and others are not. They all gather in huge family groups in the fall however to increase their survival through the winter.
For more information on Eastern Bluebirds flocking and everything else bluebird, visit http://www.sialis.org/flocks.htm. It’s a great website that can answer all your bluebird questions.