Yellow warbler

The yellow warbler was formally described in 1766 by the Swedish naturalist Carl Linnaeus in the twelfth edition of his Systema Naturae under the binomial name Motacilla petechia. The specific epithet petechia is from the Italian word petecchia "a small red spot on the skin". Linnaeus based his account on the "yellow-red pole" that had been described and illustrated in 1758 by the English naturalist George Edwards in his book Gleanings of Natural History. Edwards had obtained a specimen from the midwife Sidney Kennon. Edwards was unsure of the provenance of the specimen but in 1935 the Austrian ornithologist Carl Eduard Hellmayr designated the island of Barbados. The yellow warbler is now placed in the genus Setophaga that was introduced by the English naturalist William Swainson in 1827. The genus name Setophaga combines the Ancient Greek /, / meaning "moth" with / meaning "-eating". ==Description==

Other than in male breeding plumage and body size, all warbler subspecies are very similar. Winter, female and immature birds all have similarly greenish-yellow uppersides and are a duller yellow below. Young males soon acquire breast and, where appropriate, head coloration. Females are somewhat duller, most notably on the head. In all, the remiges and rectrices are blackish olive with yellow edges, sometimes appearing as an indistinct wing-band on the former. The eyes and the short thin beak are dark, while the feet are lighter or darker olive-buff. The 35 subspecies of S. petechia can be divided into three main groups according to the males' head color in the breeding season. Depending on subspecies, the yellow warbler may be between long, with a wingspan from . They weigh , varying between subspecies and whether on migration or not, globally averaging about but only in most breeding adults of the United States populations. Among standard measurements throughout the subspecies, the wing chord is , the tail is , the bill is and the tarsus is . The subspecies in this group mostly vary in brightness and size according to Bergmann's and Gloger's Rule. The golden warbler ('''petechia group'''; 17 subspecies Though individual birds may stray farther north, their distribution is restricted by the absence of mangrove habitat. They are generally smallish, usually weighing about or less and sometimes as little as . The summer males differ from those of the yellow warbler in that they have a rufous crown, hood or mask. The races in this group vary in the extent and hue of the head patch. The mangrove warbler ('''erithachorides group'''; 12 subspecies File:Resident adult male yellow or mangrove warbler.JPG|Resident adult male mangrove warbler S. p. bryanti, Quepos, Costa Rica File:Dendroica petechia 2446949099.jpg|Breeding male golden warbler S. p. petechia, Washington-Slagbaai National Park, Bonaire, Netherlands Antilles File:Yellow Warbler (Dendroica petechia) -Santa Cruz -Puerto Ayorto c.jpg|Breeding male mangrove warbler S. p. aureola, Puerto Ayora, Santa Cruz, Galápagos Islands File:Yellow Warbler 20090628 6831 3675254124.jpg|Breeding female S. p. aestiva, Horicon Marsh, Wisconsin, United States File:Mangrove Warbler (Setophaga petechia gundlachi) male, Cuba.jpg|Male resident Cuban yellow warbler S. p. gundlachi, Cuba File:20240504 20240504 yellow warbler pleasant valley PD203188.jpg|Male in the midst of vocalizing. Vocalizations The song is a musical strophe that can be rendered ''sweet sweet sweet, I'm so sweet, although it varies considerably between populations. The call is a soft or harder chip or ship. This is particularly frequently given by females after a male has finished his song. In territorial defense, they give hissing calls, while seet'' seems to be a kind of specialized cowbird alert (see below). Other calls are given in communication between pair-members, neighbors, or by young begging for food. These birds also communicate with postures and perhaps with touch. ==Behaviour and ecology==

s, Yukon Flats National Wildlife Refuge, Alaska, United States , Mill Creek Streamway Park, Kansas, United States American yellow warblers breed in most of North America from the tundra southwards, except for the far Southwest and the Gulf of Mexico coast. The breeding habitat of American yellow warblers is typically riparian or otherwise moist land with ample growth of small trees, in particular willows (Salix). The other groups, as well as wintering birds, chiefly inhabit mangrove swamps and similar dense woody growth. Less preferred habitats are shrubland, farmlands and forest edges. In particular American yellow warblers will come to suburban or less densely settled areas, orchards and parks, and may well breed there. Outside the breeding season, these warblers are usually encountered in small groups, but while breeding they are fiercely territorial and will try to chase away any conspecific intruder that comes along. mayflies, moths, mosquitoes, beetles, damselflies, treehoppers, other insects, insect larvae, and spiders. They acquire prey by gleaning in shrubs and on tree branches, and by hawking prey that tries to fly away. Other invertebrates and some berries and similar small juicy fruits are also eaten, the latter especially by American yellow warblers in their winter quarters. The yellow warbler is one of several insectivorous bird species that reduce the number of coffee berry borer beetles in Costa Rica coffee plantations by 50%. Caterpillars are the staple food for nestlings, with some – e.g. those of geometer moths (Geometridae) – preferred over others. The predators of yellow and mangrove warblers are those typical of such smallish tree-nesting passerines, such as snakes, foxes, birds of prey, and many others. The odds of an adult American yellow warbler surviving from one year to the next are on average 50%; in the southern populations, by contrast, about two-thirds of the adults survive each year. Conversely, less than one American yellow warbler nest in three on average suffers from predation in one way or another, while two out of three mangrove and golden warbler nests are affected. Snakes, including the blue racer (Coluber constrictor foxii) and common garter snake (Thamnophis sirtalis), are significant nest predators, taking nestlings and fledglings as well as sick or distracted adults. Likewise, corvids such as the American crow (Corvus brachyrhynchos) and blue jay (Cyanocitta cristata), and large climbing rodents, notably the American red squirrel (Tamiasciurus hudsonicus) also attack nests in this manner. These New World warblers seem to mob predators only rarely. An exception are cowbirds, which are significant brood parasites. The yellow warbler is a regular host of the brown-headed cowbird (Molothrus ater), with about 40% of all nests suffering attempted or successful parasitism. By contrast, the tropical populations are less frequent hosts to the shiny cowbird (M. bonariensis), with only 10% of nests affected. This may be due to the slightly larger size of shiny cowbirds, which are less likely to survive being fed by the much smaller warbler, compared to brown-headed cowbirds. of wild yellow warblers are around 10 years. A wintering American yellow warbler examined near Turbo, Colombia was not infected with blood parasites, unlike other species in the study. It is unclear whether this significant, but wintering birds in that region generally lacked such parasites. ==Breeding==

As usual for members of the Parulidae, yellow warblers nest in trees, building a small but very sturdy cup nest. Females and males rear the young about equally, but emphasize different tasks: females are more involved with building and maintaining the nest, and incubating and brooding the offspring. Males are more involved in guarding the nest site and procuring food, bringing it to the nest and passing it to the waiting mother, which does most of the actual feeding. As the young approach fledging, the male's workload becomes proportionally higher. Some 3–4 weeks after hatching, the young are fully independent of their parents. They become sexually mature at one year of age, and attempt to breed right away. Some 55% of all American yellow warbler nestings are successful in raising at least one young. In contrast, only 25% of mangrove warbler nests successfully fledge any offspring, with accidents and predation frequently causing total loss of the clutch. File:Dendroica petechia4.jpg|Yellow warbler nest with small clutch File:20250524 yellow warblers feeding major donnelly.webm|Male feeds another warbler ==Status and conservation==

Yellow warblers, in particular the young, devour many pest insects during the breeding season. The plumage and song of the breeding males have been described Some local decline in numbers has been found in areas, mainly due to habitat destruction and pollution. The chief causes are land clearance, the agricultural overuse of and herbicide and pesticide, and sometimes overgrazing. However, stocks will usually rebound quickly if riparian habitat is allowed to recover, particularly among the prolific American yellow warbler. (D. p. petechia) has been listed as "endangered foreign wildlife" by the United States' Endangered Species Act (ESA) since 1970; other than for specially permitted scientific, educational or conservation purposes, importing it into the US is illegal. The Californian yellow warbler (D. p./a. brewsteri) and Sonoran yellow warbler (D.p./a. sonorana) are listed as "species of concern" by the ESA. ==References==