Sittidae
Encyclopedia
Sittidae is a family of small passerine
bird
s which contains the single genus Sitta
containing about 24 species of nuthatch
es, which are found across Eurasia
and North America
.
Sometimes the Wallcreeper
(Tichodroma muraria), which is restricted to the mountains of southern Eurasia, is also placed in this family, in a separate subfamily "Tichodromadinae", in which case the nuthatches are classified in the subfamily "Sittinae". However, it is more often placed in a separate family, the Tichodromadidae. The Wallcreeper is intermediate in its morphology
between the nuthatches and the treecreeper
s, but its appearance, the texture of its plumage, and the shape and pattern of its tail suggest that it is closer to the former taxon
.
in 1828. Its closest relatives, other than the Wallcreeper
, are the treecreeper
s, and the (two or) three families are sometimes placed in a larger grouping with the wren
s and gnatcatcher
s. This superfamily
, the Certhioidea is proposed on phylogenetic
studies using mitochondrial and nuclear
DNA, and was created to cover a clade of (four or) five families removed from a larger grouping of passerine birds, the Sylvioidea
.
The Nuthatch Vanga
of Madagascar
and the sitella
s from Australia
and New Guinea
were once placed in the family Sittidae, because of similarities in appearance and lifestyle to the nuthatches, but they are not closely related, the resemblances arising from convergent evolution
to fill an ecological
niche.
and Eastern Rock Nuthatch
es use rock crevices, and the rest of the nuthatches nest in tree holes. The chicks are altricial
, which means they are blind, featherless and helpless at birth. Both parents feed the nestlings until the young birds fledge.
s are a major part of the diet for nuthatches, especially during the breeding season, but most species also eat seeds at least during the winter, when invertebrates are less readily available. Larger food items, such as big insects, snail
s, acorn
s or seeds may be wedged into cracks and hacked with the nuthatches's strong bill, this of course being the behaviour which gives that subfamily group its name. The nuthatches all store food, usually seeds, which may be pushed into crevices or into the ground, hidden under small stones, or tucked behind bark flakes; the rock nuthatches will also wedge snails into suitable crevices for consumption in times of need. Caches are recovered by memory, and can be retrieved as long as 98 days after being stored. In one study of European Nuthatches birds refrained from using their caches during benign conditions in order to save them for harsher conditions.
bird from Bavaria
which has been identified as an extinct representative of the climbing Certhioidea, a clade
comprising the treecreepers, Wallcreeper and nuthatches. It has been described as Certhiops rummeli.
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Most nuthatches have large populations and extensive geographical ranges, and present few conservation problems.
A few of the more restricted nuthatch species are threatened by deforestation.
Passerine
A passerine is a bird of the order Passeriformes, which includes more than half of all bird species. Sometimes known as perching birds or, less accurately, as songbirds, the passerines form one of the most diverse terrestrial vertebrate orders: with over 5,000 identified species, it has roughly...
bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s which contains the single genus Sitta
Nuthatch
The nuthatches are a genus, Sitta, of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs...
containing about 24 species of nuthatch
Nuthatch
The nuthatches are a genus, Sitta, of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs...
es, which are found across Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...
and North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.
Sometimes the Wallcreeper
Wallcreeper
The Wallcreeper is a small passerine bird found throughout the high mountains of Eurasia. It is the only member of the genus Tichodroma.-Taxonomy and etymology:...
(Tichodroma muraria), which is restricted to the mountains of southern Eurasia, is also placed in this family, in a separate subfamily "Tichodromadinae", in which case the nuthatches are classified in the subfamily "Sittinae". However, it is more often placed in a separate family, the Tichodromadidae. The Wallcreeper is intermediate in its morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
between the nuthatches and the treecreeper
Treecreeper
The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa. The family contains ten species in two genera, Certhia and Salpornis...
s, but its appearance, the texture of its plumage, and the shape and pattern of its tail suggest that it is closer to the former taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
.
Taxonomy
The Sittidae family was described by René-Primevère LessonRené-Primevère Lesson
René Primevère Lesson was a French surgeon, naturalist, ornithologist, and herpetologist.Lesson was born at Rochefort, and at the age of sixteen he entered the Naval Medical School there...
in 1828. Its closest relatives, other than the Wallcreeper
Wallcreeper
The Wallcreeper is a small passerine bird found throughout the high mountains of Eurasia. It is the only member of the genus Tichodroma.-Taxonomy and etymology:...
, are the treecreeper
Treecreeper
The treecreepers are a family, Certhiidae, of small passerine birds, widespread in wooded regions of the Northern Hemisphere and sub-Saharan Africa. The family contains ten species in two genera, Certhia and Salpornis...
s, and the (two or) three families are sometimes placed in a larger grouping with the wren
Wren
The wrens are passerine birds in the mainly New World family Troglodytidae. There are approximately 80 species of true wrens in approximately 20 genera....
s and gnatcatcher
Gnatcatcher
The 15-20 species of small passerine birds in the gnatcatcher family occur in North and South America . Most species of this mainly tropical and subtropical group are resident, but the Blue-gray Gnatcatcher of the USA and southern Canada migrates south in winter...
s. This superfamily
Taxonomic rank
In biological classification, rank is the level in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class. Each rank subsumes under it a number of less general categories...
, the Certhioidea is proposed on phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
studies using mitochondrial and nuclear
Cell nucleus
In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...
DNA, and was created to cover a clade of (four or) five families removed from a larger grouping of passerine birds, the Sylvioidea
Old World warbler
The "Old World Warblers" is the name used to describe a large group of birds formerly grouped together in the bird family Sylviidae. The family held over 400 species in over 70 genera, and were the source of much taxonomic confusion. Two families were split out initially, the cisticolas into...
.
The Nuthatch Vanga
Nuthatch Vanga
The Nuthatch Vanga , also known as the Coral-billed Nuthatch-vanga and formerly as the Coral-billed Nuthatch, is a species of bird in the Vangidae family.It is endemic to Madagascar....
of Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
and the sitella
Sitella
The sittellas are a family, Neosittidae, of small passerine birds found only in Australasia. They resemble nuthatches, but whilst they were considered to be in that family for many years they are now afforded their own family...
s from Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and New Guinea
New Guinea
New Guinea is the world's second largest island, after Greenland, covering a land area of 786,000 km2. Located in the southwest Pacific Ocean, it lies geographically to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago...
were once placed in the family Sittidae, because of similarities in appearance and lifestyle to the nuthatches, but they are not closely related, the resemblances arising from convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...
to fill an ecological
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
niche.
Breeding
All the species in this group nest in cavities. The WesternWestern Rock Nuthatch
The Western Rock Nuthatch, Sitta neumayer is a small passerine bird which breeds from Serbia east through Greece and Turkey to Iran. This nuthatch is largely resident apart from some post-breeding dispersal...
and Eastern Rock Nuthatch
Eastern Rock Nuthatch
The Persian Nuthatch or the Eastern Rock-nuthatch is a species of bird in the Sittidae family. It is found in Afghanistan, Armenia, Azerbaijan, Georgia, India, Iran, Iraq, Kazakhstan, Pakistan, Russia, Tajikistan, Turkey, and Turkmenistan.-References:* BirdLife International 2004. . ...
es use rock crevices, and the rest of the nuthatches nest in tree holes. The chicks are altricial
Altricial
Altricial, meaning "requiring nourishment", refers to a pattern of growth and development in organisms which are incapable of moving around on their own soon after hatching or being born...
, which means they are blind, featherless and helpless at birth. Both parents feed the nestlings until the young birds fledge.
Feeding
InvertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s are a major part of the diet for nuthatches, especially during the breeding season, but most species also eat seeds at least during the winter, when invertebrates are less readily available. Larger food items, such as big insects, snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s, acorn
Acorn
The acorn, or oak nut, is the nut of the oaks and their close relatives . It usually contains a single seed , enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1–6 cm long and 0.8–4 cm broad...
s or seeds may be wedged into cracks and hacked with the nuthatches's strong bill, this of course being the behaviour which gives that subfamily group its name. The nuthatches all store food, usually seeds, which may be pushed into crevices or into the ground, hidden under small stones, or tucked behind bark flakes; the rock nuthatches will also wedge snails into suitable crevices for consumption in times of need. Caches are recovered by memory, and can be retrieved as long as 98 days after being stored. In one study of European Nuthatches birds refrained from using their caches during benign conditions in order to save them for harsher conditions.
Fossils
The fossil record for this group appears to be restricted to a foot bone of an early MioceneMiocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
bird from Bavaria
Bavaria
Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...
which has been identified as an extinct representative of the climbing Certhioidea, a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
comprising the treecreepers, Wallcreeper and nuthatches. It has been described as Certhiops rummeli.
Status
A few of the more restricted nuthatch species are threatened by deforestation.
- The White-browed NuthatchWhite-browed NuthatchThe White-browed Nuthatch is a species of bird in the nuthatch family. It is endemic to Burma. Its natural habitat is subtropical or tropical moist montane forests....
is endangeredEndangered speciesAn endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
. The population of a few thousand birds is decreasing, and no conservation measures are in place.
- The endangered Algerian NuthatchAlgerian NuthatchThe Algerian Nuthatch, Sitta ledanti, is a small passerine bird which is the only bird species endemic to Algeria, where it is also the only nuthatch. It was first discovered in 1973....
occurs only at four known sites in Algeria, and it is possible that the total population does not exceed 1,000 birds.
- The Yunnan NuthatchYunnan NuthatchThe Yunnan Nuthatch is a species of bird in the Sittidae family. It is endemic to China .Its natural habitat is subtropical or tropical dry forests. It is becoming rare due to habitat loss.-Source:...
is vulnerableVulnerable speciesOn 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
, although still locally common.
- The Yellow-billed NuthatchYellow-billed NuthatchThe Yellow-billed Nuthatch is a species of bird in the Sittidae family. It is found in China, Laos, and Vietnam.Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montanes. It is threatened by habitat loss.-References:* BirdLife International...
is vulnerable especially on HainanHainanHainan is the smallest province of the People's Republic of China . Although the province comprises some two hundred islands scattered among three archipelagos off the southern coast, of its land mass is Hainan Island , from which the province takes its name...
, where more than 70% of the woodland has been lost in 50 years.
- The Krüper's NuthatchKrüper's NuthatchThe Krüper's Nuthatch, Sitta krueperi, is a small nuthatch. The name commemorates the German naturalist Theodor Johannes Krüper.thumb|left|Illustration by [[Joseph Wolf]], 1865-Distribution and habitat:...
is near-threatened in its stronghold in TurkeyTurkeyTurkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
, where urbanisation and development for tourism are placing considerable pressure on mature coniferous forest.