American bushtit

The American bushtit or simply bushtit (Psaltriparus minimus) is a social songbird belonging to the genus Psaltriparus. It is one of the smallest passerines in North America and it is the only species in the family Aegithalidae that is found in United States; the other seven species are found in Eurasia.

The American bushtit's distinguishing characteristics are its petite size, its plump and large head, and its long tail. Its scattered range stretches from highland parts of Mexico and the Western United States to Vancouver, via the Great Basin, the lowlands and foothills of California, southern Mexico, and Guatemala. Bushtits usually inhabits mixed open woodlands, which contains oaks and a scrubby chaparral understory. It can also be found residing in gardens and parks. Their food source is small insects, primarily, spiders in mixed-species feeding flocks.

The sharp-shinned hawk and other birds prey upon American bushtits. Bushtits live in flocks of 10 to 40 birds and family members sleep together in their large, hanging nest during breeding season. Once the offsprings develop wings that are developed enough to fly, they leave the nest and sleep on branches. The Bushtits display a unique behavior as adult males are typically the helpers that assists and raises the nestlings; hence it has intrigued many naturalists for its interesting breeding and mating patterns.

Etymology
The name "bushtit" has its earliest known origins in the Latin word parus, which stands for titmouse. The tit in titmouse comes from the Old Icelandic word titr, meaning something small.

Taxonomy
The scientific name Parus minimus was given to the bushtit after it was originally described in 1837 by American naturalist and ornithologist John Kirk Townsend, where he reported that the species inhabited the forests of the Columbia River. It is now the only species placed in the genus Psaltriparus that was introduced in 1850 by the French naturalist Charles Lucien Bonaparte. The genus name Psaltriparus combines the genus Psaltria that was introduced by Coenraad Temminck in 1836 for the pygmy bushtit with Parus that was introduced by Carl Linnaeus in 1758 for the tits.

There are 10 subspecies recognized:

The subspecies P. m. melanotis was previously considered as a separate species due to their black ears.

Description
With a length of 4.3 inches and a weight of 0.18-0.21 ounces, the American Bushtit is one of the smallest passerines in North America. It is mostly gray-brown in color, with a large head, short neck, long tail, and small, stubby beak. Moreover, bushtits have different characteristics based on their sex and habitats. The male has dark brown to black eyes while the adult female has yellow eyes. Additionally, bushtits who stay near the coast tend to have a brown "cap" or "crowns," while those further inland have a brown "mask" on their faces.

The subspecies (P. m. melanotis) can be recognized from its dark ear patch, called the auricular. This feature does not occur in the northern part of the American bushtits' range and it was first seen near the Mexican border, mainly in Texas. None of the bushtits in that location with the black ear patch are adult females; the majority of them are juvenile males with one or two dark lines on their faces rather than a whole patch. Only in the northeastern highlands Mexican highlands does the black-eared variant become more prevalent farther south; all males have a full black ear patch, and even mature females have a black arc covering their eyes and typically a black line across them.

Behavior
Bushtits usually inhabits mixed open woodlands, which contains oaks and a scrubby chaparral understory. It can also be found residing in gardens and parks. It lives under the highland parts of Mexico and the western United States to Vancouver, via the Great Basin, the lowlands and foothills of California, southern Mexico, and Guatemala.

Regarding its behavior, the American bushtit has an active and social demeanor. This species forms flocks of 10 to 40 individuals of various species, including chickadees and warblers, to forage for tiny insects and spiders in mixed-species environment. Group members frequently communicate with one another through what might be called brief spit calls.

Nesting
Both the males and females work together to construct the hanging nest, which can take up to a month to complete. The nest features a hole near the top that goes down into the nest bowl, and it hangs up to a foot below its anchor point. Using spider webs and plant material, the adults create an elastic sac. Occasionally, they sit inside the nest while it's still being built, which stretches it downward. They cover the outside with fragments of adjacent plants, including the tree the nest is made in, and add insulating materials like feathers, fur, and downy plant debris. All the adults connected to the nest, including the breeding pair and helpers, sleep there when it's in use.Typically, the couple uses the same nest for their second brood of the year. Regarding its placement, the male and female hang spiderwebs from mistletoe or other foliage to test-sites for their nests. Nest locations are typically found on tree trunks or branches, ranging in height from three to one hundred feet.

Breeding
Female Bushtits lay plain white oval eggs in batches of 4-10, but both parents share the responsibility of incubation for 11–13 days. The egg is 0.5-0.6 inches in length and 0.4 inches in width. Once the chicks hatch, both the male and female Bushtits coorperate to feed and care for them for 14–18 days. They can raise 1-2 broods a year, and older siblings from the first brood may assist in feeding the next.

During the breeding season, male and female Bushtits form pairs, actively participate in nest-building, and both engage in rearing the young. They are aided by other adult males who bring food to the nesting pair's nest. Remarkably, during this time, the entire Bushtit family sleeps together in their large, hanging nest, unlike most breeding birds where only one adult typically sleeps on the nest at a time. After the young birds fledge, they move to sleeping on branches.

However, Bushtits can be sensitive during the breeding process. If there are disturbances in the early nesting stages, they may abandon their nesting attempt and potentially seek a different mate.