Garden Warbler

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Common Name: Garden Warbler
Scientific Name: Sylvia borin

Size: 5.5 inches (14 cm); Wingspan: 6-6.6 inches (15.2-16.8 cm)

Habitat: Eurasia and Africa; the Garden Warbler breeds in most of temperate Europe (12–28°C (54–75°F)), east across temperate Asia, to the Yenisei River in Siberia. Its range extends further north than any other Sylvia warbler. All populations are migratory, wintering in sub-Saharan Africa and as far south as South Africa. Birds from central Europe initially migrate to the southwest, reorientating to the south or southeast once in Africa. Scandinavian migrants may head south through the Alps and across the Mediterranean Sea. S. b. woodwardi reaches Africa by a more easterly route, with many birds passing through the Arabian Peninsula.

The nominate subspecies occurs in the western and central parts of the winter range, although some birds occur as far east as Kenya. S. b. woodwardi winters in eastern and southern Africa. This warbler has occurred as a vagrant in Afghanistan, Djibouti, Iceland, São Tomé and Príncipe, Somalia, Yemen, Svalbard, Jan Mayen and Madeira.

Despite its name, the Garden Warbler is not a bird of gardens. Its breeding habitat includes open spaces with shady areas of thickets or herbaceous undergrowth and woodland edges adjacent to rivers or reed beds. A tolerance for willow, alder and birch allows it to breed farther north and at higher altitudes than any other European Sylvia warbler. Mature conifers and dense plantations are avoided, although young conifer plantations with thick undergrowth are suitable for nesting. In Africa, a wide range of habitats with trees are used, although closed forests and arid areas are again avoided. This warbler occurs at altitudes of up to 2,600 m (8,500 ft) in suitable mountain woodland, although in East Africa it is usually found at a lower altitude than the Blackcap, and in moister areas than the Common Whitethroat

Status: Least Concern. Global population: 54,300,000-124,000,000 individuals. In Europe, trends since 1980 show that populations have undergone a moderate decline. The Garden Warbler is hunted by Eurasian Sparrowhawks and domestic cats, and its eggs and nestlings are taken by a variety of mammalian and avian predators. It may be host to various fleas, mites and internal parasites. Also its population is under threat from the Common Cuckoo, which is a brood parasite, laying its eggs in the nests of other bird species. Despite a small population decline in much of its European range, the bird's breeding distribution is expanding northwards in Scandinavia.

Diet: Insects, berries and fruit. The Garden Warbler feeds mainly on insects in the breeding season, with other small invertebrates, such as spiders, also being eaten. It picks its prey off leaves and twigs, sometimes hovering to do so; there is a record of a mulberry fruit being taken in flight. Garden Warblers often feed with conspecifics and other fruit-eating passerines. It normally forages at less than 6 m (20 ft) above the ground. After nesting, there is a genetically controlled switch to a fruit diet, although insects are still consumed while the birds fatten prior to their migration south; birds gain weight more rapidly from a diet containing both fruit and insects than either alone. Berries and other soft fruit are preferred, and figs are particularly important for birds preparing to migrate. This predilection gives rise to the Italian beccafico (fig pecker) and Portuguese felosa-das-figueiras (fig-tree warbler) as names for this species. On this diet a bird can gain weight quickly and the liver increases the rate at which it produces fatty acids for storage in adipose tissue.

In Africa, before the birds northward migration, the warbler again eats insects as well as berries and fruit. The birds fattening even more rapidly than prior to their southward journey. Most internal organs (including the liver, spleen, intestines, kidneys and heart) and the flight muscles lose weight during the journey over the Sahara, although the testes quadruple in mass in preparation for the breeding season.

Nesting: Sexes are alike. It is a plain, long-winged and long-tailed bird with unstreaked olive-brown upper parts and dull white under parts. It has a whitish eye ring and a faint pale supercilium, and there is a buff wash to the throat and flanks. The eye is black, the legs are bluish-grey and the strong bill has a grey upper and paler grey lower mandible. Juveniles have a looser plumage than an adult, with paler and greyer upper parts and a buff tone to the under parts. The eastern subspecies S. b. woodwardi is slightly larger and paler than the nominate form with a greyer tone to the upper parts and whiter under parts.

Garden Warblers first breed when they are one year old. They are mainly monogamous. The male attracts a female to his territory through song and a display which involves rapid wing beating while perched. He will also build a number of simple nests (cock's nests) to show to his mate, although only rarely will she complete the structure, usually starting afresh. The nest is concealed in vegetation, the nature of which depends on local availability. The nest is a cup of dry grass, moss and twigs, with a soft lining of finer plant material or hair.

The first eggs are laid in late April in southern Germany, early May in northwest Europe, and late May in Finland. The season may be prolonged with some birds nesting as late as July. The clutch is typically four or five eggs, which are usually whitish or buff with grey, purple and brown blotches. The eggs are incubated for 11–12 days by both adults, although only the female stays on the nest at night. They fledge about 10 days after hatching.

Cool Facts: The Garden Warbler and its nearest relative, the Blackcap, are an ancient species pair which diverged very early from the rest of the Sylvia genus, between 12 and 16 million years ago. In the course of time, these two species have become sufficiently distinctive that they have been placed in separate subgenera, with the Blackcap in subgenus Sylvia and the Garden Warbler in Epilais. These sister species have a breeding range which extends farther northeast than all other Sylvia species except the Lesser Whitethroat and Common Whitethroat.

When Garden Warblers cross the Sahara, they fly at night, resting motionless and without feeding in suitable shade during the day. During their journey, they can metabolize not only body fat but also up to 19% of their breast and leg muscles and 39% of their digestive tract. Many birds pause for a few days to feed after the desert crossing before continuing further south.

Found in Songbird Remix Woodland Jewels

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