|Cladogram for the relationships between the extant members of Sphyrapicus, based on a 1983 genetic study.|
The yellow-bellied sapsucker is one of four species in the genus Sphyrapicus. First described by Carl Linnaeus in 1766, it is monotypic across its sizable range, although it does sometimes hybridize with red-breasted and red-naped sapsuckers. The genus name Sphyrapicus is a combination of the Greek words sphura, meaning "hammer" and pikos, meaning "woodpecker". The specific varius is Latin for "diverse".
In the genus Sphyrapicus, Williamson's sapsucker is basal, meaning that it is the earliest offshoot from the common ancestor of the genus. The less basal clade is composed of the yellow-bellied sapsucker basal to the red-breasted sapsucker and the red-naped sapsucker.
The yellow-bellied sapsucker has a length of around 19 to 21 centimetres (7.5 to 8.3 in), and an average weight of 50.3 grams (1.77 oz), although this can range anywhere from 35 to 62 grams (1.2 to 2.2 oz). The forehead is coloured bright red in the male (and very occasionally yellow), and a lighter shade of red in the female. Sometimes, this is the only place on the head a female will have red colouration, if it has any at all, as the female rarely has a black head with a few buff spots. The crown is bordered black, and is usually red, and is sometimes mixed with black in the female. There is a white stripe, starting above the eye, that extends and widens to the nape, being broken up by a thin black line on the hindneck. There is a broad black stripe going through the ear-coverts and down to the side of the neck. Below this black stripe is a white stripe that goes from the nasal tufts to the side of the breast. The throat and chin can be used to differentiated between the sexes, as they are white in the female, and red in the male.
The mantle of this sapsucker is white, and there are irregular black bars that extend from it to the rump. The lower rump is white, and the uppertail-coverts are white with some black webbing. The wing coverts are black, and there is a white panel on the medians and central greater-wing coverts. The flight feathers are black with white tips. The innermost tertials are white and black. The underwing is barred greyish and white. The uppertail is black, with some white webbing and white tips sometimes being present on the outer feathers. The underparts, excluding the pale breast and above, are tinged yellow, transitioning to a whiter colour in the lower region of them. The side of the breast down to the undertail coverts have black arrowhead-shaped markings.
The chisel-tipped bill is relatively short and straight, with a slate to blackish colour. The legs are blue-grey to green-grey in colour, and the irides are a deep brown. The juvenile is a dark olive-brown colour overall, with a buff-striped head and a streaked crown. The throat is usually white, although in the male, there may be some red. The upperparts are generally a mottled pale and blackish colour. The breast is scaly, and the central part of the belly is a very pale yellow colour. The tail is barred more than in the adult.
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They drum and give a cat-like call in spring to declare ownership of territory.
The red-naped sapsucker is distinguished by having a red nape (back of the head). The hairy woodpecker has no red on the crown (front of the head) or throat and has blacker back. The downy woodpecker has same markings as the hairy woodpecker but is significantly smaller.
Distribution and habitat
The breeding habitat of the yellow-bellied sapsucker is forested areas across Canada, eastern Alaska and the northeastern United States. They prefer young, mainly deciduous forests. There is also a disjunct population found in high elevations of the Appalachian Mountains in Virginia, Tennessee, and North Carolina. These birds winter in the eastern United States, West Indies and Central America. This species has occurred as a very rare vagrant to Ireland and Great Britain.
Ecology and behavior
The yellow-bellied sapsucker usually forages by itself, although it sometimes joins small groups in the winter, and occasionally mixes into flocks of insectivores in the winter.
Arthropods, tree sap, fruits, and nuts compose the majority of the yellow-bellied sapsucker's diet. It also takes bast and cambium from trees. Berries are occasionally eaten, and in the Northern Hemisphere spring, buds are eaten. Arthropod prey is usually in the form of Lepidoptera, Odonata, or both the young and adults of beetles and ants. During the nesting season, insects comprise about half the diet of the adults. During the late Northern Hemisphere summer and throughout the same hemisphere's autumn, sap is the primary food of choice. Cambium is taken throughout the year, although it is primarily eaten during the Northern Hemisphere winter and spring. Fruit is mainly eaten during October to February.
The chicks are fed by both sexes. The primary food is insects which are occasionally coated in tree sap before eaten by the chick. The size of these insects varies by the age of the chicks, with younger chicks being fed smaller insects. The chicks beg for food through vocalizations that can be heard 100 metres (330 ft) away or more, likely stimulating the adults to catch more food. These vocalizations are usually done by the hungriest chick, with the other joining in only when the parent is at the nest. Because of this, the hungriest chick gets fed first. When the chick leaves the nest, it relies on both insects from its parents and sap from the holes they drill.
In the breeding season, this sapsucker prefers to take sap from the trees Betula papyrifera, Acer rubrum, Amelanchier, and Populus grandidentata. Other trees of the genera Populus, Betula, and Acer are also used, in addition to deciduous trees of the genera Salix, Carya, Alnus and coniferous trees of the genera Pinus, Picea, and Abies. In the Northern Hemisphere winter and spring, it usually feeds on conifers, while in its autumn, feeding on rough-barked trees is most common.
Before feeding consistently on a tree, this sapsucker lays down exploratory bands near a live branch. These bands are laid down in horizontal rows. When it finds a tree that is photosynthesizing, then it lays down more holes to feed, about 0.5 centimetres (0.20 in) above the primary bands. These form columns. Each hole is started as an oval elongated horizontally, drilled through the bark and phloem layers to the outside of the xylem. They are then drilled further, with the sapsucker enlarging it vertically, making it yield more sap, but only for a few days. The top holes in each column thus provides phloem sap, and this sapsucker also utilizes the bast from the edges of the holes drilled. In the winter, when the holes are drilled on conifers, bast is likely the most important food.
Yellow-bellied sapsuckers nest in a large cavity excavated in a live deciduous tree, often choosing one that is has rotten heartwood; a suitable tree may be reused. It especially prefers Populus tremuloides trees that have conks of Fomes fomentarius var. populinus. Other trees in the genus Populus and those in the genus Betula are popular choices. A study in northern Canada found that the yellow-bellied sapsucker nested in trees with a diameter at breast height (DBH) ranging anywhere from 22 to 79 centimetres (8.7 to 31.1 in), with an average DBH of about 35 centimetres (14 in) for nestling trees, compared to the average DBH in the area of about 41 centimetres (16 in). A study in the northeastern United States, however, concluded that this sapsucker has a search image for trees with the ideal attributes; one of these attributes was having a DBH of 20 to 25 centimetres (7.9 to 9.8 in). The study also concluded that a deviance from this search image can be caused by the rarity of the trees that fulfill such criteria.
This bird is monogamous, and nests in pairs, with both sexes working to make the nest. Excavation of the cavity is done mostly by the male, with excavation usually being done continuously for 15 to 30 minutes at a time. Excavation takes about 15 to 28 days, although further hollowing out is done by both sexes after the chicks hatch. The cavity itself is anywhere from 2 to 20 metres (6.6 to 65.6 ft) above ground, although it is usually found between heights of 3 and 14 metres (9.8 and 45.9 ft). This sapsucker is also territorial, with territories having a radius ranging from about 46 to 137 metres (150 to 450 ft) away from the nest. Territories in less wooded areas are often larger than those in areas heavily wooded.
The male usually arrives on the nesting grounds about one week before the female. The sapsucker arrives early in the Northern Hemisphere spring, often before heavy snowfall has stopped. The actual breeding season is from April to July.
This bird lays a clutch of four to seven eggs, with clutches being larger for birds in the northern part of the range. The eggs themselves are white and spotless, measuring around 24 by 17 millimetres (0.94 by 0.67 in). During egg laying, the female is dominate, sometimes driving the male away from the nest. Both sexes incubate the eggs during the 10 to 13 day incubation period, with the male usually doing so over the night. Sapsuckers are restless but quiet during this time, and the eggs are left uncovered about 16% of the time during the incubation period. Weather usually does not affect incubation, although on particularly hot days, the parents incubate the eggs for less time. When the chicks hatch, they are brooded for 8 to 10 days by both sexes. Nests with less young are brooded more, presumably because smaller broods lose heat faster. After 25 to 29 days, the young leave the nest for this first time, and become independent after about two weeks.
Status and conservation
The yellow-bellied sapsucker is considered to be least concern by the IUCN, even though it has a decreasing population. This is because of its large range of about 7,830,000 square kilometres (3,020,000 sq mi). In addition, it has a large population, being common in its range, although it is not easily seen when not breeding. It has low genetic diversity; about half of that of most birds.
Relationship with humans
Damage to trees
Because yellow-bellied sapsuckers feed on up to 250 species of living trees and woody plants, they are sometimes considered to be a pest. The birds can cause serious damage to trees, and intensive feeding has been documented as a source of tree mortality. Sapsucker feeding can kill a tree by girdling, which occurs when a ring of bark around the trunk is severely injured. Certain tree species are particularly susceptible to dying after being damaged by yellow-bellied sapsuckers. For example, a USDA forest study that examined trees injured by yellow-bellied sapsuckers noted a mortality of 67% for gray birch (Betula populifolia), 51% for paper birch (Betula papyrifera), and 40% for red maple (Acer rubrum). In other tree species, injuries inflicted by yellow-bellied sapsuckers can result in significantly less mortality. The USDA study noted that only 3% of Red Spruce (Picea rubens) and 1% of Hemlock (Tsuga canadensis) that were injured by sapsuckers succumbed to their wounds.
In orchards, the USDA recommends allowing yellow-bellied sapsuckers to feed upon their preferred tree(s), suggesting the birds will focus their attention on these and spare the rest of the orchard from serious damage. Non-lethal deterrents can also be applied to trees to ward off the birds, including burlap wraps and bird tanglefoot (a type of sticky repellent). In commercial aspen plantations, yellow-bellied sapsuckers can be drawn to a stand by individual trees infested by the fungus Fomes igniarius. Infested trees are prone to heartwood decay, which provides prime habitat for sapsuckers to carve nesting holes. Therefore, infested trees should be eliminated to prevent colonization of commercial aspen stands by sapsuckers.
- BirdLife International (2012). "Sphyrapicus varius". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Johnson, Ned K.; Zink, Robert M. (1983). "Speciation in sapsuckers (Sphyrapicus): I. Genetic differentiation". The Auk. 100 (4): 871–884.
- "ITIS Report: Sphyrapicus". Integrated Taxonomic Information System. Retrieved 30 April 2013.
- "ITIS Report: Sphyrapicus varius". Integrated Taxonomic Information System. Retrieved 30 April 2013.
- Ted Floyd (27 May 2008). Smithsonian Field Guide to the Birds of North America. HarperCollins. p. 277. ISBN 978-0-06-112040-4.
- Jobling, James A (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 362, 398. ISBN 978-1-4081-2501-4.
- Winkler, H.; Christie, David A.; Kirwan, G.M. (2017). del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi; Christie, David A.; de Juana, Eduardo, eds. "Yellow-bellied Sapsucker (Sphyrapicus varius)". Handbook of the Birds of the World Alive. Barcelona, Spain: Lynx Edicions. Retrieved 21 October 2017. (Subscription required (. ))
- Alderfer, Jonathan; Dunn, Jon Lloyd (2014). National Geographic Complete Birds of North America. National Geographic. p. 400. ISBN 978-1-4262-1373-1.
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- Beal, Foster Ellenborough Lascelles (1911). Food of the woodpeckers of the United States. Washington, D.C.: U.S. Dept. of Agriculture, Biological Survey. pp. 27–31.
- Hauber, Mark E. (1 August 2014). The Book of Eggs: A Life-Size Guide to the Eggs of Six Hundred of the World's Bird Species. Chicago: University of Chicago Press. p. 369. ISBN 978-0-226-05781-1.
- Kilham, Lawrence (1962). "Breeding behavior of yellow-bellied sapsuckers". The Auk. 79 (1): 31–43. doi:10.2307/4082449. ISSN 0004-8038.
- Eberhardt, Laurie S. (2000). "Use and selection of sap trees by yellow-bellied sapsuckers". The Auk. 117 (1): 41–51.
- Beach, Chandler B., ed. (1914). "Sap-Sucker". The New Student's Reference Work. Chicago: F. E. Compton and Co.
- Kilham, Lawrence (1971). "Reproductive behavior of yellow-bellied sapsuckers I. Preference for nesting in Fomes-infected aspens and nest hole interrelations with flying squirrels, raccoons, and other animals". The Wilson Bulletin. 83 (2): 159–171.
- Savignac, C.; Machtans, C.S. (2006). "Habitat requirements of the yellow-bellied sapsucker, Sphyrapicus varius, in boreal mixedwood forests of northwestern Canada". Canadian Journal of Zoology. 84 (9): 1230–1239. doi:10.1139/z06-112. ISSN 0008-4301.
- Kilham, Lawrence (1977). "Nesting behavior of yellow-bellied sapsuckers". The Wilson Bulletin. 89 (2): 310–324.
- Howell, Thomas R. (1952). "Natural history and differentiation in the yellow-bellied sapsucker". The Condor. 54 (5): 237–282. doi:10.2307/1364941. ISSN 0010-5422.
- "How to Identify and Control Sapsucker Injury on Trees". North Central Forest Experiment Station, St. Paul, MN: USDA. Retrieved 30 January 2013.
- Rushmore, Francis (1969). "Sapsucker: Damage Varies with Tree Species and Seasons" (PDF). Forest Service Research Paper NE-136. Northeastern Forest Experiment Station, Upper Darby, PA: USDA.
|Wikimedia Commons has media related to Yellow-bellied sapsucker.|
|Wikispecies has information related to Sphyrapicus varius|
- Yellow-bellied sapsucker Species Account - Cornell Lab of Ornithology
- Yellow-bellied sapsucker - Sphyrapicus varius - USGS Patuxent Bird Identification InfoCenter
- Stamps (for Antigua and Barbuda, Barbuda, Dominica, El Salvador, Nevis-(Saint Kitts and Nevis), Turks and Caicos Islands) at bird-stamps.org
- "Yellow-bellied sapsucker media". Internet Bird Collection.
- Yellow-bellied sapsucker photo gallery at VIREO (Drexel University)
- Project sapsucker at the Royal Alberta Museum
- yellow-bellied sapsucker damage to trees - Natural Resources Canada
- Yellow-bellied sapsucker Natural History Notebooks