sandorski sandorski:
$1:
Milder winters mean the birds don't need to expend as much energy shivering, and can get by eating less food in the day.
Why? Makes sense to me.
If they can do better in warmer climates, why move north.Birds will move to find an area which provides ample food and safety to raise their young.
Many of their traditional breeding area's are now sub-divisions.
Like I said, the article does not provide the real underlying reason(s) why bird migration patterns shift and therefore is just another straw grasping exercise from the AGW crowd.
Ask the birds.