Yellow-bellied Sapsucker (Sphyrapicus varius)

[order] PICIFORMES | [family] Picidae | [latin] Sphyrapicus varius | [UK] Yellow-bellied Sapsucker | [FR] Pic macule | [DE] Gelbbauch-Saftlecker | [ES] Carpintero Bebedor (Cr), Chupasavia Comun (Mex), Checo Panza Amarilla (HN) | [NL] Geelbuiksapspecht

Subspecies

Physical charateristics

The male has a red forecrown on a black and white head and a red throat. Sexual dimorphism between the adults is easily observed as the female has a white chin compared to the red in the male. The back is blackish, with a white rump, and a large white wing patch. The underparts are yellowish and are paler in females. Juvenile woodpeckers retain a brown plumage until late in the winter when it begins to take on the colors of its sex.

Listen to the sound of Yellow-bellied Sapsucker

[audio:http://www.aviflevoland.nl/sounddb/Y/Yellow-bellied Sapsucker.mp3]

Copyright remark: Most sounds derived from xeno-canto

Range

North America : North

Habitat

They live in northern deciduous and mixed coniferous forests in summer. During winter they live in forests and various semi-open habitats.

Reproduction

The breeding range of the Yellow-bellied Sapsucker covers most of the boreal zone from east-central Alaska to southern Newfoundland. It dips south into northeastern Iowa and western Maryland, with isolated populations in the Alleghenies and Smokies. Canada’s boreal forests support roughly 55% of the population. Males arrive about a week ahead of females and establish territories by means of the drumming cadence distinctive of sapsuckers: a short roll followed by a pause and then several individual strikes or abbreviated rolls. Both sexes often return to the previous year’s nest territory, so re-pairings are common. They often use the same tree and sometimes the same cavity. Males do almost all the excavation of new cavities, over a period of 7-20 days; females contribute more when time is short, such as after failed nest attempts. Cavities are most often in diseased deciduous trees, especially quaking aspen infected with heartwood decay fungus. The four to six eggs are incubated by both sexes for 10-13 days and the young fledge over a 2-3 day period at 25-30 days of age. The parents lure the young out of the nest with food, and the fledglings do not reenter the cavity. Family groups remain together near sap wells, the young gradually learning to feed themselves, first on sap and later on insects. There is only one brood per year.

Feeding habits

The sapsuckers’ feeding behavior is the most distinctive feature of their ecology. Sap, directly or indirectly, contributes significantly to their diet, and most of their foraging time is spent creating, maintaining, inspecting, and feeding from sap wells. Sap itself makes up only about 20% of the overall diet of this species, though at certain times, the figure can be 100%. Sap is consumed for its sugar, which varies in content by tree species and season; trees are selected based more on sugar content than on sap flow. Higher amino acid content in the sap of trees entering senescence may make such trees attractive. Sap is consumed more when its sugar content is higher and when the birds’ energetic needs are higher, such as during molt. Wells usually are dug into phloem tissues, which are closer to the surface; during early spring, however, the underlying xylem tissues have higher sugar content (to fuel leaf growth), and sapsuckers drill through the phloem to reach them. Phloem wells begin as slits and gradually are widened into rectangles; xylem wells are round holes. Sapsuckers vigorously defend their wells against conspecifics, other birds, and even many insects that might be considered food under other circumstances. Most of the remainder of the diet consists of insects, especially ants (34% of the total diet and 68% of the summer diet); most are exposed by flaking off bark or caught in flight near sap wells but some are collected from the wells themselves. Sometimes insects are dipped into the sap. Sapsuckers also consume fruit, seeds, leaf buds, and, perhaps incidentally, some bast.

Conservation

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Migration

Southward migration begins in September, females departing first and adult males last. Migration is primarily well east of the Rocky Mountains, mostly at night and often in flocks. Males typically winter in the U.S., from Kansas and Long Island south, while most females travel to the West Indies, Mexico, and Central America; birds at the northern edge are virtually all male and those at the southern extreme female. Spring migration is essentially a mirror image of fall migration. Males typically arrive on the breeding grounds by late March in the south, early May in the north.

Distribution map