Today my yard sounded like there were some 30 bushtits, tsking about. Busy little birds, some of my favorites. Although they are perhaps not as showy as some of the little birds, they are INNOCENTS. We have a nest from some years back. It is shaped liked a soft, spongey sock. It has a hole in the top and is about 8 inches long. The eggs and then the babies are way down in the bottom of the nest and the parents enter and exit through the hole.
I was able to find a picture of a couple of nests. They REALLY feel spongey, all moss and soft things these little birds have collected. More than anything, all the BIMBY (Birds In My Back Yard), require WATER. Many people don't realize how important this is.....MORE important than food when the weather is dry. Birds need to bath to get the dust off. VERY IMPORTANT. Using a tray that you would use beneath a plant is a great bird bath. I hung one using a plant hanger a few years ago and it was pretty cool seeing 8 or 9 little bushtits taking a bath.