I'd assume that spring buds and flowers are a very welcome and important change in nutrition for many birds, compared to what's been available during the bleak winter months. I took a couple of photos last spring of a Wood Duck eating big leaf maple flowers. It consumed several clusters as it moved through the branches. The other photo is of a Golden-crowned Sparrow that was devouring red elderberry buds at quite a pace.

http://www.pbase.com/rodg/image/41759680

http://www.pbase.com/rodg/image/41866865

Rod Gilbert, Olympia
rodgilbert1 at comcast.net