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The piculets are a distinctive subfamily of small woodpeckers which occur mainly in tropical South America, with just three Asian and one African species. Like the true woodpeckers, piculets have large heads, long tongues which they use to extract their insect prey and zygodactyl feet, with two toes pointing forward, and two backwards. However, but they lack the stiff tail feathers that the true woodpeckers use when climbing trees, so they are more likely than their relatives to perch on a branch rather than an upright trunk. Their bills are shorter and less dagger-like than the true woodpeckers, so they look for insects and grubs mainly in decaying wood. Similarly, they re-use woodpecker holes for nesting, rather than making their own holes. The eggs are white, as with many hole nesters. Typically these birds have grey or dull green upperparts and dark-streaked white underparts. ==Systematics and evolution== Although not well known from fossils, the evolution of piculets is now considered rather straightforward. The disjunct occurrence of the genera, with one African species of the Southeast Asian ''Sasia'' and one Southeast Asian species of the American ''Picumnus'' is of comparatively recent origin. Molecular dating, calibrated with geographic events in the absence of a good fossil record, points at the Late Miocene, c. 8 MYA, as the point where the two genera divided into their two respective lineages. At that time, there was a notable global cooling period. The molecular distances between piculets and woodpeckers are comparatively small for subfamilies, agreeing with the hypothesis that the split between the three groups of woodpecker-like picids subfamilies occurred only during the Miocene climate optimum, around 15 MYA. The later radiation of South American piculets is probably due to changes in topology and climate fluctuations during the Pliocene and Pleistocene. The genus ''Verreauxia'' may be accepted because of pronounced morphological similarities, but the two ''Picumnus'' lineages, despite having diverged long ago, are virtually alike except for head coloration (Fuchs ''et al.'', 2006). The Antillean piculet (''Nesoctites micromegas'') has proven to be a very distinct species evolutionarily between piculets and woodpeckers (Benz ''et al.'', 2006) and thus is nowadays placed in a subfamily of its own. The arrangement of species in the genera follows del Hoyo ''et al.'' (2002). Genus ''Picumnus'' * Speckled piculet, ''Picumnus innominatus'' (sometimes ''Vivia'') * Bar-breasted piculet, ''Picumnus aurifrons'' * Orinoco piculet, ''Picumnus pumilus'' * Lafresnaye's piculet, ''Picumnus lafresnayi'' * Golden-spangled piculet, ''Picumnus exilis'' * Black-spotted piculet, ''Picumnus nigropunctatus'' * Ecuadorian piculet, ''Picumnus sclateri'' * Scaled piculet, ''Picumnus squamulatus'' * White-bellied piculet, ''Picumnus spilogaster'' * Arrowhead piculet, ''Picumnus minutissimus'' * Spotted piculet, ''Picumnus pygmaeus'' * Speckle-chested piculet, ''Picumnus steindachneri'' * Varzea piculet, ''Picumnus varzeae'' * White-barred piculet, ''Picumnus cirratus'' * Ocellated piculet, ''Picumnus dorbygnianus'' * Ochre-collared piculet, ''Picumnus temminckii'' * White-wedged piculet, ''Picumnus albosquamatus'' * Rusty-necked piculet, ''Picumnus fuscus'' * Rufous-breasted piculet, ''Picumnus rufiventris'' * Tawny piculet, ''Picumnus fulvescens'' * Ochraceous piculet, ''Picumnus limae'' * Mottled piculet, ''Picumnus nebulosus'' * Plain-breasted piculet, ''Picumnus castelnau'' * Fine-barred piculet, ''Picumnus subtilis'' * Olivaceous piculet, ''Picumnus olivaceus'' * Greyish piculet, ''Picumnus granadensis'' * Chestnut piculet, ''Picumnus cinnamomeus'' Genus ''Verreauxia'' (sometimes included in ''Sasia'') * African piculet, ''Verreauxia africana'' Genus ''Sasia'' * Rufous piculet, ''Sasia abnormis'' * White-browed piculet, ''Sasia ochracea'' 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Piculet」の詳細全文を読む スポンサード リンク
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