Black-headed grosbeak | |
---|---|
Male in California, United States | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Cardinalidae |
Genus: | Pheucticus |
Species: | P. melanocephalus |
Binomial name | |
Pheucticus melanocephalus (Swainson, 1827) | |
Breeding Migration Year-round Nonbreeding |
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 crow 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 monarch butterfly or simply monarch is a milkweed butterfly in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. It is among the most familiar of North American butterflies and an iconic pollinator, although it is not an especially effective pollinator of milkweeds. Its wings feature an easily recognizable black, orange, and white pattern, with a wingspan of 8.9–10.2 cm (3.5–4.0 in). A Müllerian mimic, the viceroy butterfly, is similar in color and pattern, but is markedly smaller and has an extra black stripe across each hindwing.
Cardinalidae is a family of New World-endemic passerine birds that consists of cardinals, grosbeaks, and buntings. It also includes several other genera such as the tanager-like Piranga and the warbler-like Granatellus. Membership of this family is not easily defined by a single or even a set of physical characteristics, but instead by molecular work. Among songbirds, they range from average-sized to relatively large, and have stout features, some species with large, heavy bills.
The evening grosbeak is a passerine bird in the finch family Fringillidae found in North America.
The rose-breasted grosbeak, colloquially called "cut-throat" due to its coloration, is a large, seed-eating grosbeak in the cardinal family (Cardinalidae). It is primarily a foliage gleaner. Males have black heads, wings, backs, and tails, and a bright rose colored patch on their white breast. Males and females exhibit marked sexual dimorphism.
Asclepias is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to humans and many other species, primarily due to the presence of cardenolides. However, as with many such plants, some species feed upon milkweed leaves or the nectar from their flowers. A noteworthy feeder on milkweeds is the monarch butterfly, which uses and requires certain milkweeds as host plants for their larvae.
The yellow grosbeak, also known as the Mexican yellow grosbeak, is a medium-sized seed-eating bird in the same family as the northern cardinal, "tropical" or "New World" buntings, and "cardinal-grosbeaks" or New World grosbeaks.
Butterfly gardening is a way to create, improve, and maintain habitat for lepidopterans including butterflies, skippers, and moths. Butterflies have four distinct life stages—egg, larva, chrysalis, and adult. In order to support and sustain butterfly populations, an ideal butterfly garden contains habitat for each life stage.
The black-thighed grosbeak is a large seed-eating bird in the family Cardinalidae, which is endemic to the mountains of Costa Rica and western Panama.
The black-backed grosbeak is a bird in the family Cardinalidae, the cardinals or cardinal grosbeaks. It is found in Argentina, Brazil, Bolivia, Colombia, Ecuador, Paraguay, Peru, and Venezuela. They are often kept as cagebirds.
The black-faced grosbeak is a large seed-eating bird in the cardinal family (Cardinalidae), which is a resident breeding species from south-eastern Mexico to eastern Panama.
Asclepias asperula, commonly called antelope horns milkweed or spider milkweed, is a species of milkweed native to the Southwestern United States and northern Mexico.
Euchaetes egle, the milkweed tiger moth or milkweed tussock moth, is a moth in the family Erebidae and the tribe Arctiini, the tiger moths. The species was first described by Dru Drury in 1773. It is a common mid- through late summer feeder on milkweeds and dogbane. Like most species in this family, it has chemical defenses it acquires from its host plants, in this case, cardiac glycosides. These are retained in adults and deter bats, and presumably other predators, from feeding on them. Only very high cardiac glycoside concentrations deterred bats as predators. Adults indicate their unpalatability to bats with ultrasonic clicks from their tymbal organs.
Asclepias curassavica, commonly known as tropical milkweed, is a flowering plant species of the milkweed genus, Asclepias. It is native to the American tropics and has a pantropical distribution as an introduced species. Other common names include bloodflower or blood flower, cotton bush, hierba de la cucaracha, Mexican butterfly weed, redhead, scarlet milkweed, and wild ipecacuanha.
A cardenolide is a type of steroid. Many plants contain derivatives, collectively known as cardenolides, including many in the form of cardenolide glycosides (cardenolides that contain structural groups derived from sugars). Cardenolide glycosides are often toxic; specifically, they are heart-arresting. Cardenolides are toxic to animals through inhibition of the enzyme Na+/K+-ATPase, which is responsible for maintaining the sodium and potassium ion gradients across the cell membranes.
The citreoline trogon is a species of bird in the family Trogonidae. It is endemic to western Mexico, with an estimated distribution size of 539,000 km2 Due to this very large range, the IUCN consider it a species of Least Concern and that the current population trend is stable. T. citreolus has also been studied as an Ecosystem engineer.
Calotropin is a toxic cardenolide found in plants in the family Asclepiadoideae. In extreme cases, calotropin poisoning can cause respiratory and cardiac failure. Accidental poisoning is common in livestock who have ingested milkweed. Calotropin is commonly stored as a defense mechanism by insects that eat milkweeds as their main food source.