Gnatcatcher
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The gnatcatchers are a family of small
passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...
bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s called ''Polioptilidae''. The 22 species occur in
North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...
and
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
(except for the far south and the high
Andean The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...
regions). Most species of this mainly
tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...
and
subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...
group are resident, but the blue-grey gnatcatcher of the United States and southern
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
migrates south in winter. They are close relatives of the
wren Wrens are a family, Troglodytidae, of small brown passerine birds. The family includes 96 species and is divided into 19 genera. All species are restricted to the New World except for the Eurasian wren that is widely distributed in the Old Worl ...
s.Atwood, J. & Lerman, S. (2006) Family Polioptilidae (Gnatcatchers). pp. 350–377 in: del Hoyo, J., A. Elliott, and D. Christie. eds (2006). ''
Handbook of Birds of the World The ''Handbook of the Birds of the World'' (HBW) is a multi-volume series produced by the Spanish publishing house Lynx Edicions in partnership with BirdLife International. It is the first handbook to cover every known living species of bird. ...
'' Vol. 11. Old World Flycatchers to Old World Warblers. Lynx Edicions, Barcelona.


Description

These dainty birds are intermediate between
Old World warbler The Old World warblers are a large group of birds formerly grouped together in the bird family Sylviidae. They are not closely related to the New World warblers. The family held over 400 species in over 70 genera, and were the source of much taxo ...
s and
wren Wrens are a family, Troglodytidae, of small brown passerine birds. The family includes 96 species and is divided into 19 genera. All species are restricted to the New World except for the Eurasian wren that is widely distributed in the Old Worl ...
s in their structure and habits, moving restlessly through foliage seeking insects. The gnatcatchers are mainly soft bluish grey in color, and have the typical insectivore's long sharp bill. Many species have distinctive black head patterns (especially males) and long, regularly cocked, black-and-white tails. The skulking gnatwrens are browner, more thickset, and with proportionally shorter tails and longer bills.


Distribution and habitat

They are distributed from
North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...
to
South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...
, with the exception of the far south and high
Andean The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...
regions. Gnatwrens typically occur in the undergrowth of dense, often humid, forest, while gnatcatchers, depending on the species involved, occur in anything from dry scrubby habitats (e.g. the California gnatcatcher) to the
canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...
of humid Amazonian forest (e.g. the Guianan gnatcatcher). The North American species nest in bushes or trees, but the breeding behavior of several of the
Neotropical The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In biogeogra ...
species is essentially unknown.


Taxonomy and systematics

A species new to science, the
critically endangered An IUCN Red List critically endangered (CR or sometimes CE) species is one that has been categorized by the International Union for Conservation of Nature as facing an extremely high risk of extinction in the wild. As of December 2023, of t ...
Iquitos gnatcatcher '' Polioptila clementsi'', was first described in 2005.Whitney, B. & Alonso, A. (2005) A new species of gnatcatcher from the white-sand forests in northern Amazonian Peru with revision of the ''Polioptila guianensis'' complex. ''Wilson Bull.'' 117(2): 113-210. This species is a member of the Guianan gnatcatcher '' Polioptila guianensis'' complex, which recently has been proposed split into three species (four with the Iquitos gnatcatcher), but not all authorities have accepted this (e.g. SACC). Furthermore, other groups should possibly be split, notably the tropical gnatcatcher '' Polioptila plumbea'' and masked gnatcatcher '' Polioptila dumicola'' complexes, but at present scientific papers on these matters are lacking. The family contains 22 species divided into 3 genera: *''
Ramphocaenus ''Ramphocaenus'' is a genus of passerine bird from South America. Species ''Ramphocaenus'' contains the following species: * Chattering gnatwren (''Ramphocaenus sticturus'') * Trilling gnatwren (''Ramphocaenus melanurus'') References

{{T ...
'' (2 species) – gnatwrens *'' Microbates'' (2 species) – gnatwrens *''
Polioptila ''Polioptila'' is a genus of small insectivorous birds in the family Polioptilidae. They are found in North and South America. The genus ''Polioptila'' was introduced by the English zoologist Philip Sclater in 1855. Although he listed several ...
'' (18 species) – gnatcatchers


California Gnatcatcher

The California gnatcatcher (''Polioptila californica'') is a small, non-migratory songbird that inhabits the coastal regions of southern
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
. It belongs to the family ''Polioptilidae'' and is best known for its distinctive behavior and appearance. This species is characterized by a small, slender body, typically around 10 cm in length, with a long tail, dark gray or bluish-gray plumage, and a faint black line running through its eye. The California gnatcatcher is an important species in the coastal sage scrub ecosystem, which it relies on for both food and shelter.


Natural habitat

The natural habitat of the California gnatcatcher is primarily the coastal sage scrub ecosystem. This type of habitat is found in areas with a Mediterranean climate—mild, wet winters and hot, dry summers. The gnatcatcher favors areas with low shrubs and a mix of grasses and wildflowers, where it can easily find insects. It also lives in chaparral and mixed woodlands but is most commonly found below 1,000 meters in elevation. The coastal sage scrub once stretched across much of southern California, from Santa Barbara to
San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...
, but has been drastically reduced by urban sprawl and agricultural development.


Food

The California gnatcatcher feeds primarily on insects, such as small flies, beetles, ants, and other invertebrates. It uses its sharp beak to catch these insects in the dense vegetation of its habitat. The gnatcatcher is particularly skilled at foraging in the low shrubbery and in the underbrush, where its small size allows it to maneuver with agility. The species is an insectivore, and its diet is essential for providing the energy it needs for survival and reproduction. It also consumes some seeds and berries, but insects make up the bulk of its diet.


Population

Over the years, the population of the California gnatcatcher has fluctuated dramatically. In the early 1990s, the population was estimated to be only 1,000 to 3,000 pairs due to habitat destruction, primarily from urban expansion. As southern California grew, vast areas of coastal sage scrub were converted into housing developments, agriculture, and infrastructure, which resulted in the loss of the gnatcatcher's habitat. The species was listed as threatened under the U.S. Endangered Species Act in 1993, prompting conservation efforts to protect its remaining habitats. Today, the population is estimated to be around 20,000 to 40,000 individuals. thanks to restoration and preservation projects.


Status

The California gnatcatcher is classified as a threatened species, primarily due to habitat loss and fragmentation. Urbanization, agriculture, and climate change have significantly reduced the available coastal sage scrub habitat. Habitat fragmentation isolates populations, making it difficult for gnatcatchers to find mates and reproduce, which also reduces genetic diversity. While some recovery has been made, the species is still vulnerable, and its long-term survival depends on continued conservation efforts. Protected areas and habitat restoration have been critical in stabilizing the population in recent years. Behaviorally, California gnatcatchers are highly territorial, especially during the breeding season. They use a combination of vocalizations and physical displays to defend their territories from other birds. These birds are also known for their distinctive foraging behavior. They often move quickly through shrubs, flicking their tails and catching insects in mid-air or from leaves. The gnatcatcher is an agile and persistent forager, spending much of its day hunting for food to sustain itself. The species is also known for being relatively solitary outside of the breeding season, with pairs coming together only for nesting.


Predators

As small birds, California gnatcatchers face several natural predators. They are vulnerable to a variety of avian predators, including hawks, kestrels, and ravens, which may prey upon them or their eggs. Additionally, snakes and raccoons are known to threaten their nests. These predators often target the eggs or fledglings, making early life particularly dangerous for the gnatcatcher. In order to avoid predators, gnatcatchers rely on their excellent camouflage and the dense vegetation of the coastal sage scrub to hide from potential threats. California gnatcatchers are also particularly vulnerable to wildfires, which have become more frequent and intense due to climate change. Wildfires can destroy vast swaths of their habitat, leaving them without food and shelter. These fires can decimate entire populations and disrupt their breeding cycles. To ensure their survival, California gnatcatchers depend on the preservation of their habitat and the continuation of conservation efforts that focus on restoring degraded areas and protecting the species' remaining habitat from further destruction.


References


External links


Gnatcatcher videos
on the Internet Bird Collection {{Taxonbar, from=Q752549 * Birds of the Americas Taxa named by Spencer Fullerton Baird