Nesting Material

Swallows are busy building nests now.  We have been watching a pair of Barn Swallows thru our dinning window gather mud from a mud puddle to daub a nest together up under the porch at the office.  Today I caught this Tree Swallow with nesting material headed for her nest box. She and I were both in sight of the nest box, but she would not give it away by going there until I had left.  Although I wanted to get a photo of her at the nest box, I finally took pity on her and walked on.