Pheucticus melanocephalus is found throughout most of western North America, from the Pacific to the eastern foothills of the Rocky Mountains. These birds winter in Mexico and spend the remainder of the year throughout western United States and Canada, from Montana through Oregon and along the Pacific coast to Baja, California. Black-headed grosbeaks are found as far east as Kansas and Oklahoma and north throughout the provinces of Saskatchewan and British Columbia.
Biogeographic Regions: nearctic (Native ); neotropical (Native )
Though little is known about predators of adult black-headed grosbeaks, although domestic and feral cats (Felis silvestris) have been known to eat adult birds. Eggs and nestlings are taken by a variety of predators, ranging from other birds, such as western scrub-jays (Aphelocoma californica) and magpies (Pica), to snakes, rock squirrels (Spermophilus variegatus), deer mice (Peromyscus), chipmunks, striped skunks (Mephitis mephitis), raccoons (Procyon lotor), and weasels (Mustela). This is countered by aggressive nest defense by parent birds, who attack egg predators with their sharp, large beaks.
Known Predators:
Black-headed grosbeaks have the distinctive grosbeak bill, which is large, conical, thick, and straw-colored. Both genders have yellow wing linings. Females differ in color from males, featuring brown to dark grey feathers with a striped head, back, and sides, a paler bill, white wing bar, and a tan breast. Their more colorful male counterparts have white patches on the wings, a black and white tail, and black head with bright orangish-brown underparts and red legs. They are from 15 to 20 cm in length, with wingspans from 30 to 33 cm, and weighing from 38 to 54 grams.
Range mass: 38 to 54 g.
Range length: 15 to 20 cm.
Range wingspan: 30 to 33 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
In the wild, black-headed grosbeaks have an expected lifespan between 5 and 6 years. In captivity, however, they have lived as long as 25 years.
Range lifespan
Status: captivity: 25 (high) years.
Average lifespan
Status: wild: 143 months.
Black-headed grosbeaks prefer deciduous and broad-leaved evergreen woods, nesting in thickets on the edges of open woods, ponds, swamps, or streams, or in small trees.
Range elevation: 1,524 to 2,743 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest
Wetlands: swamp
Other Habitat Features: riparian
Black-headed grosbeaks prey mainly on insects and other invertebrates during the breeding season, including spiders, beetles, scale insects, flies, wasps, bees, grasshoppers, codling moth caterpillars, and cankerworms. They also eat small fruits, such as cherries, blackberries, raspberries, strawberries, elderberries, and mistletoe berries; as well as buds and seeds, which they can crack open with their large and sturdy bill. Black-headed grosbeaks forage in trees and shrubs, predominantly obtaining food from gleaning. They come readily to feeding stations and campgrounds. Their winter diet is mostly unknown.
Animal Foods: insects; terrestrial non-insect arthropods
Plant Foods: seeds, grains, and nuts; fruit
Primary Diet: omnivore
Black-headed grosbeak eggs provide food for a multitude of predators, including all those mentioned in predation, above. They are also predators of insects and other terrestrial invertebrates, impacting their populations, and act to disperse seeds of the fruit they eat. Brown-headed cowbirds (Molothrus ater) infrequently form a parasitic relationship with grosbeaks in Kansas, Nebraska, Colorado, Utah, and Montana. A nest parasite, cowbirds lay eggs in black-headed grosbeak nests, which are then raised by the grosbeak "parents".
Ecosystem Impact: disperses seeds
Commensal/Parasitic Species:
Black-headed grosbeaks tend to eat insects that we consider pests, such as caterpillars, moths, and flies. These are popular birds among birdwatching enthusiasts, especially when they build their large, cuplike nests, often adorned with flowers.
Positive Impacts: ecotourism ; controls pest population
There are no known adverse effects of Pheucticus melanocephalus on humans.
Black-headed grosbeaks are under no known danger and are protected under the United States Migratory Bird Treaty Act.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Black-headed grosbeaks have a distinct song which resembles its close relative, rose-breasted grosbeaks (Pheucticus ludovicianus). This song is similar to that of a robin or western tanager, but richer and clearer, containing whistled notes, trills, and a back-and-forth warble. Males sing to declare territory and attract females, while females use song while foraging, to communicate or respond to other females, and to maintain contact with their offspring. Black-headed grosbeaks also use visual cues in communication, such as in assessing mates and responding to young.
Communication Channels: visual ; acoustic
Other Communication Modes: choruses
Perception Channels: visual ; polarized light ; tactile ; acoustic ; chemical
Black-headed grosbeaks can hybridize with their close relatives rose-breasted grosbeaks (Pheucticus ludovicianus). In ranges where the two species overlap, they cannot distinguish between their calls, sometimes leading to mixed species pairs.
Pheucticus melanocephalus is also known by the following names: common grosbeak; western grosbeak; and Rocky Mountain grosbeak.
Black-headed grosbeaks are monogamous. Males arrive in the spring about six days before the females, remaining solitary until the females arrive. Males sing to establish territory and attract mates. Older males get higher quality territories, and fighting for territory can be aggressive, as black-headed grosbeaks attack swiftly during flight. Once females arrive, males will sing from perches near females, occasionally flying up into the air while singing a courtship song.
Mating System: monogamous
Black-headed grosbeak females build a nest between 4 and 25 feet above the ground over a period of 3 to 4 days, usually in deciduous trees; especially willows and coast live oaks. The nest could also be located in shrubs, bordering streams, or more rarely, gardens and parks. The nest itself is constructed thinly and loosely with twigs, rootlets, and other plant materials and placed in the dense outer foliage of a tree or shrub near an opening.
Black-headed grosbeaks produce one brood per year in the spring and early summer, from April to July. They lay 2 to 5 eggs per season. The eggs vary in color from greenish or bluish to spotted brown. Eggs hatch in 12 to 13 days with all eggs hatching within a 24 hour period. Young fledge after about 12 days, becoming independent after another 14 days. Females reach reproductive maturity around 1 year, while males mature after 3 years.
Breeding interval: Black-headed grosbeaks produce one brood every year.
Breeding season: Copulation and nesting for Pheucticus melanocephalus occurs from April through July.
Range eggs per season: 2 to 5.
Average eggs per season: 3-4.
Range time to hatching: 12 to 13 days.
Range fledging age: 11 to 15 days.
Range time to independence: 23 to 30 days.
Range age at sexual or reproductive maturity (female): 1 to 1 years.
Range age at sexual or reproductive maturity (male): 2 to 4 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average eggs per season: 3.
Both sexes invest time incubating the eggs, alternating sitting periods throughout the 12 to 13 days of incubation. Occasionally, both parents will sit on the nest and sing simultaneously. In a similar fashion, both parents feed their nestlings, and females occasionally use song to communicate with their young. Males depart for breeding grounds earlier, leaving females to feed their fledged young.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)
The black-headed grosbeak (Pheucticus melanocephalus) is a medium-sized, seed-eating bird in the family Cardinalidae. It is sometimes considered conspecific with the rose-breasted grosbeak (P. ludovicianus) with which it hybridizes on the American Great Plains.
The 19 cm (7.5 in) long, 47 g (1.7 oz) black-headed grosbeak is a migratory bird, with nesting grounds from southwestern British Columbia, through the western half of the United States, into central Mexico. It occurs as a vagrant further south in Central America.
Measurements:[2]
The black-headed grosbeak is similar in size to a common starling. As per its name, the male has a black head, and black wings and tail with prominent white patches. Its breast is dark to tawny orange in color, and its belly is yellow. The female has a brown head, neck, and back with sparrow-like black streaks. She also has white streaks down the middle of her head, over her eyes, and on her cheeks. Her breast is white, and wings and tail are grayish-brown with two white wing bars and yellowish wing edges.
The black-headed grosbeak prefers to live in deciduous and mixed wooded areas. It likes to be in areas with large trees and thick bushes, such as patches of broadleaved trees and shrubs within conifer forests, including streamside corridors, river bottoms, lakeshores, wetlands, and suburban areas.
Females build nests among the dense foliage on an outer branch of tall broadleaved trees or shrubs, 3–35 ft (0.91–10.67 m) above ground. They occasionally build in dense shrubs such as blackberry. The nest is in the shape of an open saucer, made of fine grass, rootlets, twigs, bark, and conifer needles. It is often lined with rootlets, hair, and fine plant material. The female lays two to five pale green, blue, or gray eggs that are spotted with reddish and dark brown. The eggs are incubated by the male and female for 12–14 days. After the eggs have hatched, the fledglings leave the nest in about 11 or 12 days, but they are unable to fly for another two weeks. The young are fed by both adults. The black-headed grosbeak's monogamy is under study, but pair bonds generally last for only one breeding season. They typically have one brood per season, though two broods have been documented in foothills of the Sacramento Valley in California.
The grosbeak's song is a rich warble that is similar to that of an American robin, but more fluent, faster, softer, sweeter, and mellow with rising and falling passages that make the song much longer than the robin's. The note is a sharp ik or eek. Both the male and female sing, but have different songs.
The black-headed grosbeak eats pine and other seeds, berries, insects and spiders, and fruit. During the summer, it mostly eats spiders, snails, and insects. It is one of the few birds, along with the black-backed oriole, that can safely eat the poisonous monarch butterfly. In their wintering grounds, this grosbeak consumes many monarch butterflies, perhaps over one million per year in the overwintering colonies in Mexico.[3] However, only the black-headed grosbeak is physiologically insensitive to the cardiac glycoside heart poisons in the monarchs, which monarch caterpillars sequester from their milkweed host plants and are retained by adults even after metamorphosis, which protects them from most predaceous birds.[3] The same genetic changes that confer resistance to the poisons in the monarch and its relatives were found to have evolved in the black-headed grosbeak in a case of convergent evolution.[4] The cellular target of the heart poisons is the first extracellular loop of the sodium pump, a critical ion pump needed for nerve cells to fire and heart cells to contract. Two of the grosbeak's four copies of the gene encoding this protein have changes that are also found in insects adapted to feeding on plants producing the cardiac glycosides. In one of the copies, it has the same genetic changes at position 111 and 119 as in the common grow and other Euploea butterflies closely related to the monarch, and in another copy, position 111 has the same change as Largus bugs, which feed on dogbane plants that produce cardiac glycosides[4] The mutations at positions 111 and 119 have been shown together, but not alone, to confer resistance to the heart poisons in insects through positive, intramolecular epistasis.[5] In the breeding season, the black-headed grosbeak comes to bird feeders for sunflower and other types of seed, and fruit, and also joins northern orioles at feeders with grape jelly.
Black-headed grosbeaks range from the Pacific Coast to the middle of the US Great Plains and from southwestern Canada to the mountains of Mexico. US and Canadian birds are highly migratory, wintering in Mexico. In the Great Plains, the range of the black-headed grosbeak and the rose-breasted grosbeak overlap and they have interbred somewhat. After the breeding season, they tend to seek out berry-rich areas. They migrate south early in the fall and return to the north late in the spring and have been known to do so in flocks.
Black-headed grosbeaks frequently sing from prominent perches. Both the male and female sing, but have different songs, and both are known to sing from the nest while incubating. When trying to court a female, males fly with their wings and tails spread. They forage in the foliage, on the ground, or in low vegetation and are prominent berry eaters. When feeding the chicks sing to their mother, rustling wings and displaying their yellow under-feathers (see image).
The birdcall is just delightful. The chick sings to its mother, calling for food; seeds she has cracked open and shelled.[6]
The black-headed grosbeak (Pheucticus melanocephalus) is a medium-sized, seed-eating bird in the family Cardinalidae. It is sometimes considered conspecific with the rose-breasted grosbeak (P. ludovicianus) with which it hybridizes on the American Great Plains.
The 19 cm (7.5 in) long, 47 g (1.7 oz) black-headed grosbeak is a migratory bird, with nesting grounds from southwestern British Columbia, through the western half of the United States, into central Mexico. It occurs as a vagrant further south in Central America.
