Bewick’s Wren

• At the sound of approaching humans, a female Bewick’s Wren incubating eggs usually flushes quietly from her nest cavity, but remains nearby and scolds. Some females, however, sit tightly on their eggs even when disturbed.
• The open cup may be lined with feathers, wool, hair, or plant down, with a final inner lining of snakeskin.
• Bewick’s Wrens usually build their nests in cavities or on ledges within 30 feet of the ground. Males often begin the process, with the female contributing equally by the end.

Mountain Chickadee

• Inside the cavity, the female makes a neat cup from fur she gathers. She also makes a fur plug or cap that she uses to cover her eggs when she leaves the cavity.
• Early in the breeding season, the male leads the female to cavities in his territory and may enter while she watches. She ultimately selects the cavity.
• Renesting attempts and second clutches are in different cavities from the first attempt, but both boxes and natural cavities often are reused in subsequent years.

Chestnut-backed Chickadee

• The Chestnut-backed Chickadee uses lots of fur in making its nest, with fur or hair accounting for up to half the material in the hole. The adults make a layer of fur about a half-inch thick that they use to cover the eggs when they leave the nest.
• Males take the first step in choosing nest sites, approaching a possible location while the female watches. Later, the female decides on the site, enters the cavity, and accepts pieces of vegetation brought by the male.
• Chestnut-backed Chickadees prefer nest boxes oriented in an eastern to southeastern direction.

American Robin

• The robin’s nest is an open cup of grass and twigs held together with a thick layer of mud and lined with fine dry grass.
• Females build the nest from the inside, pressing dead grass and twigs around them into a cup shape using the wrist of one wing.
• Because the robin forages largely on lawns, it is vulnerable to pesticide poisoning and can be an indicator of chemical pollution.

Wood Duck

• The Wood Duck nests in trees near water, sometimes directly over water, but other times up to a mile away.
• If nest boxes are placed too close together, many females lay eggs in the nests of other females.
• The female lines the nest with down feathers she takes from her breast.

California Scrub-Jay

• California Scrub-Jay and Woodhouse’s Scrub-Jay were considered a single species known as Western Scrub-Jay until 2016.
• Both members of a pair help with nest-building.
• Either sex selects a nest site and initiates nest construction. A potential nest site is indicated to the mate by making an undulating flight to the site while producing loud flight vocalizations, often while carrying nest material. Wheeze vocalizations are produced upon approach to the site.
• Nests are often well hidden amid foliage, vines, and mistletoe.
• Scrub-Jays frequently constructs nest platforms, especially at the onset of nesting season, that are never used.

Woodhouse’s Scrub-Jay

• Woodhouse’s Scrub-Jay and California Scrub-Jay were considered a single species known as Western Scrub-Jay until 2016.
• Both members of a pair help with nest-building.
• Either sex selects a nest site and initiates nest construction. A potential nest site is indicated to the mate by making an undulating flight to the site while producing loud flight vocalizations, often while carrying nest material. Wheeze vocalizations are produced upon approach to the site.
• Scrub-Jays frequently construct nest platforms, especially at the onset of nesting season, that are never used.
• Nests are often well hidden amid foliage and vines.

Western Bluebird

• A paired male and female search for nest sites together, inspecting cavities to see if they are suitable.
• The females do almost all of the nest construction, gathering grasses, straw, pine needles, moss, other plant fibers, and fur from the ground and carrying it to the nest. She lines the nest cup with grasses, rootlets, feathers, horsehair, and sometimes bits of plastic.
• Western Bluebirds exhibit cooperative breeding; 2–14% of pairs have helpers at the nest. Helpers are typically juveniles from a previous brood, although adults may also help nesting pairs if they do not have their own territory or if their own nest has failed.
• Western Bluebirds can nest up to three times per season.

Red-winged Blackbird

• The Red-winged Blackbird is a highly polygynous species, meaning males have many female mates – up to 15 in some cases. Typically 5 or more females have to crowd their nests into any one male’s territory.
• Second broods are rare for this species, but they can occur if time permits.
• Hatching is asynchronous and usually takes place just after sunrise.

Say’s Phoebe

• Say’s Phoebe will use the old nests of other birds, particularly those of swallows and other phoebes.
• Say’s Phoebe has benefited from the use of human-made structures for nest sites.
• A pair may investigate potential nest sites together; the male engages in nest-showing displays while the female may show nest-shaping movements (i.e., rotating from side to side) at prospective sites.

Northern Mockingbird

• The male and female construct the nest together; the male usually begins the nest with the outer foundation while the female finishes up the inner lining.
• Northern Mockingbirds rarely ever reuse their nests.
• In the beginning of the nesting season mockingbirds can take more than two weeks to finish a nest, but later in the season they can build a nest in as little as three days, laying an egg on the day the nest is completed.

Mourning Dove

• Members of a pair preen each other with gentle nibbles around the neck as a pair-bonding ritual. Eventually, the pair will progress to grasping beaks and bobbing their heads up and down in unison.
• Mourning Doves sometimes reuse their own or other species’ nests.
• Mourning Doves commonly build nests in hanging flower pots or other human-made structures.

Mountain Bluebird

• Historically, the Mountain Bluebird depended for its nest sites on tree cavities excavated by woodpeckers, but the increased provisioning of nest boxes has created new breeding opportunities.
• While showing off nest cavities, males give their most elaborate display: sing on or near the structure housing the nest cavity and at the entrance, and fly back and forth between a perch near the female and the nest cavity itself (sometimes this is accompanied by male copulation attempts).
• Only the female builds the nest. The male sometimes acts as if he is helping, but he either brings no nest material or he drops it on the way.

Lesser Goldfinch

• Lesser Goldfinches are often found in suburban habitats, like parks and gardens.
• The nest is usually in a twig fork of a tree, mostly hidden by foliage or lichens.
• The female, which builds most of the nest without help from the male, begins by collecting plant materials with her beak. The materials can include leaves, bark, catkins, yucca fibers, cocoons and spiderwebs. Sometimes she strips branches of their fibers, holding them with her feet.

House Wren

• The House Wren song is long and complex, and both males and females sing.
• As the season progresses, House Wren nests can become infested with mites and other parasites that feed on the wren nestlings. Perhaps to fight this problem, wrens often add spider egg sacs into the materials they build their nests from. In lab studies, once the spiders hatched, they helped the wrens by devouring the nest parasites.
• The House Wren is a fierce competitor for nest holes. They will harass and peck at much larger birds, sometimes dragging eggs and young out of a nest site they want – even occasionally killing adult birds.

House Finch

• House Finches nest in a variety of deciduous and coniferous trees as well as on cactus and rock ledges.
• Searching for nest sites is a conspicuous behavior throughout the nesting season. Females appear to do most prospecting, but males follow closely and often re-examine each site searched by the female.
• House Finches feed their nestlings exclusively plant foods, a fairly rare occurrence in the bird world. Many birds that are vegetarians as adults still feed animal foods to keep their fast-growing young supplied with protein.

Gray Catbird

• The male Gray Catbird uses his loud song to proclaim his territory. He uses a softer version of the song when near the nest or when a bird intrudes on his territory. The female may sing the quiet song back to the male.
• Females build the nests, with males sometimes supplying materials.
• The Gray Catbird’s long song may last for up to 10 minutes.

Black-capped Chickadee

• Both members of a pair will excavate a nest cavity in rotten wood, or enlarge an abandoned woodpecker cavity.
• Chickadees often incorporate moss and animal fur into their nests, which the female builds.
• Parental behavior during egg laying includes some mate-guarding, and “courtship” feeding is particularly prominent in response to broken “dee” vocalizations.

Barn Swallow

• Breeding areas must contain a source of mud (such as a river bank) for incorporation into the nest structure. In drought-prone areas, you can make a Barn Swallow nest cup.
• Barn Swallows will sometimes reuse old nests, but they avoid ones heavily infested with mites or parasites. They will clean out the old feathers and add new mud to the rim.
• Barn Swallows once nested in caves throughout North America, but now build their nests almost exclusively on human-made structures.

American Kestrel

• Kestrels add no nesting material to their simple scrape nest within a cavity.
• Rarely, kestrels will nest in the old nest of another bird species.
• The male searches for possible nest cavities. When he’s found suitable candidates, he shows them to the female, who makes the final choice.

American Goldfinch

• American Goldfinches breed later than most North American birds. They wait to nest until June or July when milkweed, thistle, and other plants have produced their fibrous seeds, which goldfinches incorporate into their nests and also feed their young.
• Goldfinches are among the strictest vegetarians in the bird world, selecting an entirely vegetable diet and only inadvertently swallowing an occasional insect.
• The nest is constructed by the female in 3 stages. Stage 1 involves building an open cup of twigs connected by spider silk. In stage 2, a tighter cup of small roots and plant debris is formed. During stage 3, a soft lining of plant pappus or other “downy” material is added to line the nest.

Dark-eyed Junco

• It’s rare for a junco to reuse a nest.
• Female juncos choose their nest site, most commonly on the ground near a protruding rock or roots for cover.
• Occasionally juncos nest near human-made structures like window sills, beams, or hanging plants.

Spotted Towhee

• Ground nests are built into depressions so that the nest rim is at the soil surface or only slightly above it.
• They often choose fairly exposed areas over sites deep inside a thicket, but within these areas they find a clump of grass, a log, or the base of a shrub to conceal their nests against.
• Only the female builds the nest, but both parents care for hatched young.

Lazuli Bunting

• The female constructs the nest alone; her mate is usually nearby but does not participate in building.
• The nest is typically built low in dense, well-shaded bushes.
• Silk from tent caterpillars (Malacosoma spp.) and spider webs are often wrapped around outer portions of the nest.

Indigo Bunting

• The female Indigo Bunting builds the nest alone—a process that takes up to 8 days early in the season and as little as 2 days later in the summer.
• She locates the nest in a crotch or fork where branches meet, amid a supporting network of vertical and diagonal twigs.
• The nest cup is about 1.5 inches deep inside, with an outside diameter of 3 inches and an inside diameter of 2 inches.

Black-headed Grosbeak

• Black-headed Grosbeak nests are widely reported to be so thinly constructed that eggs can be seen through the bottom.
• The male Black-headed Grosbeak shares about equally with the female in incubating eggs and feeding young.
• Nests are typically placed in the outer branches of a small deciduous tree or bush near a stream.

Blue Grosbeak

• In the southern part of its breeding range, the Blue Grosbeak commonly raises two broods per year.
• Brown-headed Cowbirds commonly lay eggs in Blue Grosbeak nests.
• Many nests incorporate snake skins, but researchers are unsure why.

Brown Thrasher

• The Brown Thrasher nests in dense shrubs, especially those with thorns.
• An aggressive defender of its nest, the Brown Thrasher is known to strike people and dogs hard enough to draw blood.
• Occasionally reuses nests built in previous years.

Song Sparrow

• The female builds the nest, working mainly during the morning.
• Females may start but then abandon 1 or 2 (rarely 3) nests before completing the nest that eventually receives eggs.
• For the first 4 days after hatching, the female closely broods the young.

Purple Martin

• The Purple Martin is a colony-nesting species, readily using nest boxes with multiple compartments (more common in the east) or individual hollowed gourds strung close together (more common in the west).
• Purple Martins compete with House Sparrows and European Starlings for nesting sites. By keeping compartments closed until Purple Martins return to their breeding habitat, you can help reduce this competition.
• The best place to install a martin house is in an open area near water.

Ash-throated Flycatcher

• The Ash-throated Flycatcher frequently uses human-made structures for nesting. It readily uses nest boxes, as well as pipes, fence posts, ledges under eaves or porches, and even in clothes hanging on a clothesline.
• Unlike most members of its genus, the Ash-throated Flycatcher only occasionally uses snakeskin in its nest. Only 5% of nests examined contained reptile skin, but 98% had mammal hair (particularly rabbit fur).
• Incubation is done by the female only; the male will bring food and supplementary nest material to the incubating female.

Juniper Titmouse

• Nests of the Juniper Titmouse are often placed in crevices in twisted trunks of larger, older juniper trees.
• The incubating female sits very tight on the nest while incubating, and will hiss like a snake if disturbed.
• Nests may be reused by the same or a different pair in subsequent years.

Oak Titmouse

• The Oak Titmouse mates for life, and pairs defend year-round territories.
• The female is primarily responsible for nest construction; during this time, the male is increasingly attendant to her, feeding her inside the cavity and accompanying her while she gathers nest material.
• The nest is primarily built of grass, moss, hair, and feathers.

Violet-green Swallow

• Violet-green Swallows commonly nest in small colonies of up to 25 nests, but isolated pairs have been reported nesting in dead trees, especially near lakes and streams.
• The female is the primary nest builder and can take from six days to three weeks.
• During egg-laying and incubation, the male brings feathers with which to line the nest.

Tree Swallow

• Tree Swallows seem to prefer south-facing nest boxes, all else being equal.
• Nesting Tree Swallows need nearby bodies of water over which to forage for flying insects.
• The nest is lined with feathers, usually those of waterfowl.