For most birds, Spring is the time for singing and nest building. This tiny 4.5 inch passerine is the only bird in it’s family found in North America. What makes the Bushtit (BUSH) so special is not the song, just a few buzzing chips and pips, or it’s solo family status, but their amazing nest building skills.
The Bushtit weaves a footlong hanging pouch with a small one inch hole near the top. Other descriptions of the nest include hanging jug, gourd or sock. Both the male and female construct the nest. They start by hanging spider webs from twigs in different locations and then decide which to actually hang the nest from. The outside weave consists of twigs, grasses, moss, lichen, leaves, and spider web. Inside the nest is lined with soft materials such as plant down, fur, and feathers. During construction the birds will go into the bottom of the nest to stretch it down which helps to achieve the oblong shape. The elastic properties of the spider web is important as a binder to hold the nest shape. Additionally, other Bushtits will help the mating pair build their nest. Oddly enough, the assisting builders are usually males. A nest can take two week to as much as 50 days to build.
After the nest is complete, 5 to 7 half inch eggs are laid and incubated by both the female and male. This is unusual because most incubating males develop a partial brood patch, the Bushtit male does not. Only the female has a brood patch for incubation. The eggs hatch within two weeks and the male, female and assisting nest builders will feed the hatchlings. All providers will roost in the nest at night too. There can be as many as 10 to 12 birds down into the base. The young birds leave the nest after 18 days, but remain nearby and continue to be fed by all adults for several days. They will huddle together to stay warm. Often the nest is reused for a second brood. The breeding pair are monogamous and will stay together for several years.
The Bushtit is a common bird in Skagit County. It is a year-round resident and is usually observed in feeding flocks, calling and moving from tree to tree as they forage for insects and spiders. These flocks can range from 20 to as many as 60 birds and may include other species such as chickadees and kinglets. Their preferred habitat is the forest edge, particularly along streams and coastlines. They look for insects under leaves giving them the reputation of tiny acrobatic birds. During winter they are attracted to suet feeders. In breeding season they pair up and break into smaller communities. Mating birds will tolerate the presence of other Bushtits nearby.
What they lack in colorful plumage, they gain in cuteness. They have a plump round appearance with mostly gray-brown feathers. Their tiny black bills are perfect for gleaning insects. They have a relatively long tail and black legs. The only distinguishing field mark between male and female are their irises. The male and all juveniles have black irises. The female develops a cream color iris as she matures. The oldest recorded Bushtit was a captured and released banded female. She was at least 9 years old.
This spring, look for Bushtits gathering nesting material to weave their incredible hanging baskets. Finding a nest can be more difficult, but look for them near tree trunks starting around 3 feet and higher. These birds are only found in western North America. In Washington State they are most common west of the Cascades.