40-595: The Antillean piculet ( Nesoctites micromegas ) is a species of bird in subfamily Picinae of the woodpecker family Picidae. It is endemic to the Caribbean island of Hispaniola that is shared by the Dominican Republic and Haiti . The Antillean piculet is the only member of genus Nesoctites . The species is evolutionarily distinct from the other piculets , and some taxonomists afford it its own subfamily Nesoctitinae. A fossil feather in amber attributed to
80-698: A better sense of smell. A third stage of bird evolution starting with Ornithothoraces (the "bird-chested" avialans) can be associated with the refining of aerodynamics and flight capabilities, and the loss or co-ossification of several skeletal features. Particularly significant are the development of an enlarged, keeled sternum and the alula , and the loss of grasping hands. † Anchiornis † Archaeopteryx † Xiaotingia † Rahonavis † Jeholornis † Jixiangornis † Balaur † Zhongjianornis † Sapeornis † Confuciusornithiformes † Protopteryx † Pengornis Ornithothoraces † Enantiornithes Warm-blooded Warm-blooded
120-473: A definition similar to "all theropods closer to birds than to Deinonychus ", with Troodon being sometimes added as a second external specifier in case it is closer to birds than to Deinonychus . Avialae is also occasionally defined as an apomorphy-based clade (that is, one based on physical characteristics). Jacques Gauthier , who named Avialae in 1986, re-defined it in 2001 as all dinosaurs that possessed feathered wings used in flapping flight , and
160-442: A group called Paraves . Some basal members of Deinonychosauria, such as Microraptor , have features which may have enabled them to glide or fly. The most basal deinonychosaurs were very small. This evidence raises the possibility that the ancestor of all paravians may have been arboreal , have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, studies suggest that
200-529: A higher basal metabolic rate and can further increase their metabolic rate during strenuous activity. They usually have well-developed insulation in order to retain body heat: fur and blubber in the case of mammals and feathers in birds. When this insulation is insufficient to maintain body temperature, they may resort to shivering —rapid muscle contractions that quickly use up ATP, thus stimulating cellular metabolism to replace it and consequently produce more heat. Additionally, almost all eutherian mammals (with
240-408: A red crown spot, and have obscure barring rather than streaks on their underparts. Subspecies N. m. abbotti is paler than the nominate and has less yellow on the crown, grayer upperparts, a plainer white throat, and less heavy streaks on the underparts. The nominate subspecies of Antillean piuculet is found throughout the main island of Hispaniola. N. m. abbotti is restricted to Gonâve Island off
280-498: A relatively large amount of fruit. The Antillean piculet's breeding season is from February to July. It excavates a nest hole or occupies one abandoned by another woodpecker, typically within 5 m (16 ft) of the ground in a stump, tree, palm, or fence post. Pairs are highly territorial and will aggressively call and display towards intruders. The clutch size is two to four eggs; the incubation period and time to fledging are not known. [REDACTED] The Antillean piculet has
320-406: A sister group, the order Crocodilia , contain the only living representatives of the reptile clade Archosauria . During the late 1990s, Aves was most commonly defined phylogenetically as all descendants of the most recent common ancestor of modern birds and Archaeopteryx lithographica . However, an earlier definition proposed by Jacques Gauthier gained wide currency in the 21st century, and
360-717: A time, sometimes for years, and rarely for life. Other species have breeding systems that are polygynous (one male with many females) or, rarely, polyandrous (one female with many males). Birds produce offspring by laying eggs which are fertilised through sexual reproduction . They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Many species of birds are economically important as food for human consumption and raw material in manufacturing, with domesticated and undomesticated birds being important sources of eggs, meat, and feathers. Songbirds , parrots, and other species are popular as pets. Guano (bird excrement)
400-404: A variety of vocalizations. Members of a pair use "kuk-ki-ki-ki-ke-ku-kuk" as a contact and territorial call. Its alarm calls are "mechanical 'pit' and 'pew' notes" and it makes a "continuous noisy 'yeh-yeh-yeh-yeh' chatter during fights". In contrast to many other woodpeckers, it is not known to drum. [REDACTED] Bird Birds are a group of warm-blooded vertebrates constituting
440-496: Is generated by metabolism . This relates to the chemical reaction in cells that break down glucose into water and carbon dioxide , thereby producing adenosine triphosphate (ATP), a high-energy compound used to power other cellular processes. Muscle contraction is one such metabolic process generating heat energy, and additional heat results from friction as blood circulates through the vascular system. All organisms metabolize food and other inputs, but some make better use of
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#1732855087525480-455: Is a year-round resident throughout its range. The Antillean piculet mostly forages in the forest understorey below about 8 m (26 ft), but will feed in the crown as well. It mostly hunts by gleaning small branches, twigs, and vines rather than tree trunks, and also probes flowers and clusters of leaves and pine needles. It hunts singly or in pairs. Its diet is mostly insects, especially ants and beetles, and includes other arthropods and
520-412: Is an informal term referring to animal species whose bodies maintain a temperature higher than that of their environment. In particular, homeothermic species (including birds and mammals ) maintain a stable body temperature by regulating metabolic processes. Other species have various degrees of thermoregulation . As there are more than two categories of temperature control utilized by animals,
560-434: Is browish olive with a bronze cast. Their cheeks are dull whitish with olive barring, their chin and throat white with a faint yellow tinge, and the rest of their underparts pale yellowish white. The throat has a few small dark spots and the breast and belly have wide dark streaks. Adult females are larger than males and have the same plumage except without the red crown spot. Juveniles are overall duller than adults, do not have
600-533: Is called ornithology . Birds are feathered theropod dinosaurs and constitute the only known living dinosaurs . Likewise, birds are considered reptiles in the modern cladistic sense of the term, and their closest living relatives are the crocodilians . Birds are descendants of the primitive avialans (whose members include Archaeopteryx ) which first appeared during the Late Jurassic . According to recent estimates, modern birds ( Neornithes ) evolved in
640-429: Is harvested for use as a fertiliser. Birds figure throughout human culture. About 120 to 130 species have become extinct due to human activity since the 17th century, and hundreds more before then. Human activity threatens about 1,200 bird species with extinction, though efforts are underway to protect them. Recreational birdwatching is an important part of the ecotourism industry. The first classification of birds
680-503: Is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor. Over 40% of key traits found in modern birds evolved during the 60 million year transition from the earliest bird-line archosaurs to the first maniraptoromorphs , i.e. the first dinosaurs closer to living birds than to Tyrannosaurus rex . The loss of osteoderms otherwise common in archosaurs and acquisition of primitive feathers might have occurred early during this phase. After
720-516: Is synonymous to Avifilopluma. † Scansoriopterygidae † Eosinopteryx † Jinfengopteryx † Aurornis † Dromaeosauridae † Troodontidae Avialae Based on fossil and biological evidence, most scientists accept that birds are a specialised subgroup of theropod dinosaurs and, more specifically, members of Maniraptora , a group of theropods which includes dromaeosaurids and oviraptorosaurs , among others. As scientists have discovered more theropods closely related to birds,
760-479: Is the largest piculet, and is about double the size of the Neotropical piculets of genus Picumnus . Adult males of the nominate subspecies have a lemon yellow crown with an orange-red to red patch in the center. Their hindneck is yellowish green and their upperparts dull olive green to yellow-green with a faint rusty-bronze tinge. Their wings are olive green and the flight feathers have yellow-green edges. Their tail
800-530: Is used by many scientists including adherents to the PhyloCode . Gauthier defined Aves to include only the crown group of the set of modern birds. This was done by excluding most groups known only from fossils , and assigning them, instead, to the broader group Avialae, on the principle that a clade based on extant species should be limited to those extant species and their closest extinct relatives. Gauthier and de Queiroz identified four different definitions for
840-715: The Late Cretaceous and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 million years ago, which killed off the pterosaurs and all non- ornithuran dinosaurs. Many social species preserve knowledge across generations ( culture ). Birds are social, communicating with visual signals, calls, and songs , and participating in such behaviour as cooperative breeding and hunting, flocking , and mobbing of predators. The vast majority of bird species are socially (but not necessarily sexually) monogamous , usually for one breeding season at
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#1732855087525880-660: The Tiaojishan Formation of China, which has been dated to the late Jurassic period ( Oxfordian stage), about 160 million years ago. The avialan species from this time period include Anchiornis huxleyi , Xiaotingia zhengi , and Aurornis xui . The well-known probable early avialan, Archaeopteryx , dates from slightly later Jurassic rocks (about 155 million years old) from Germany . Many of these early avialans shared unusual anatomical features that may be ancestral to modern birds but were later lost during bird evolution. These features include enlarged claws on
920-581: The class Aves ( Latin: [ˈaveːs] ), characterised by feathers , toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart , and a strong yet lightweight skeleton . Birds live worldwide and range in size from the 5.5 cm (2.2 in) bee hummingbird to the 2.8 m (9 ft 2 in) common ostrich . There are over 11,000 living species and they are split into 44 orders . More than half are passerine or "perching" birds. Birds have wings whose development varies according to species;
960-428: The appearance of Maniraptoromorpha, the next 40 million years marked a continuous reduction of body size and the accumulation of neotenic (juvenile-like) characteristics. Hypercarnivory became increasingly less common while braincases enlarged and forelimbs became longer. The integument evolved into complex, pennaceous feathers . The oldest known paravian (and probably the earliest avialan) fossils come from
1000-509: The birds that descended from them. Despite being currently one of the most widely used, the crown-group definition of Aves has been criticised by some researchers. Lee and Spencer (1997) argued that, contrary to what Gauthier defended, this definition would not increase the stability of the clade and the exact content of Aves will always be uncertain because any defined clade (either crown or not) will have few synapomorphies distinguishing it from its closest relatives. Their alternative definition
1040-665: The earliest members of Aves, is removed from this group, becoming a non-avian dinosaur instead. These proposals have been adopted by many researchers in the field of palaeontology and bird evolution , though the exact definitions applied have been inconsistent. Avialae, initially proposed to replace the traditional fossil content of Aves, is often used synonymously with the vernacular term "bird" by these researchers. † Coelurus † Ornitholestes † Ornithomimosauria † Alvarezsauridae † Oviraptorosauria Paraves Most researchers define Avialae as branch-based clade, though definitions vary. Many authors have used
1080-451: The first avialans were omnivores . The Late Jurassic Archaeopteryx is well known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. Archaeopteryx was the first fossil to display both clearly traditional reptilian characteristics—teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It
1120-478: The genus has been found in the Dominican Republic, showing that the ancestors of the species have been isolated on Hispaniola for at least 25 million years. The Antillean piculet has two subspecies, the nominate N. m. micromegas ( Sundevall , 1866) and N. m. abbotti ( Wetmore , 1928). The Antillean piculet is 14 to 16 cm (5.5 to 6.3 in) long and weighs 26 to 33 g (0.92 to 1.2 oz). It
1160-649: The only known exception of swine ) have brown adipose tissue whose mitochondria are capable of non-shivering thermogenesis . This process involves the direct dissipation of the mitochondrial gradient as heat via an uncoupling protein , thereby "uncoupling" the gradient from its usual function of driving ATP production via ATP synthase . In warm environments, these animals employ evaporative cooling to shed excess heat, either through sweating (some mammals) or by panting (many mammals and all birds)—mechanisms generally absent in poikilotherms. It has been hypothesized that warm-bloodedness evolved in mammals and birds as
1200-523: The only known groups without wings are the extinct moa and elephant birds . Wings, which are modified forelimbs , gave birds the ability to fly, although further evolution has led to the loss of flight in some birds , including ratites , penguins , and diverse endemic island species. The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds , have further evolved for swimming. The study of birds
1240-402: The outermost half) can be seen in the evolution of maniraptoromorphs, and this process culminated in the appearance of the pygostyle , an ossification of fused tail vertebrae. In the late Cretaceous, about 100 million years ago, the ancestors of all modern birds evolved a more open pelvis, allowing them to lay larger eggs compared to body size. Around 95 million years ago, they evolved
Antillean piculet - Misplaced Pages Continue
1280-443: The output than others. Like all energy conversions, metabolism is rather inefficient, and around 60% of the available energy is converted to heat rather than to ATP. In most organisms, this heat dissipates into the surroundings. However, endothermic homeotherms (generally referred to as "warm-blooded" animals) not only produce more heat but also possess superior means of retaining and regulating it compared to other animals. They exhibit
1320-514: The past three decades, investigations in the field of animal thermophysiology have unveiled numerous species within these two groups that do not meet all these criteria. For instance, many bats and small birds become poikilothermic and bradymetabolic during sleep (or, in nocturnal species, during the day). For such creatures, the term heterothermy was introduced. Further examinations of animals traditionally classified as cold-blooded have revealed that most creatures manifest varying combinations of
1360-528: The previously clear distinction between non-birds and birds has become blurred. By the 2000s, discoveries in the Liaoning Province of northeast China, which demonstrated many small theropod feathered dinosaurs , contributed to this ambiguity. The consensus view in contemporary palaeontology is that the flying theropods, or avialans , are the closest relatives of the deinonychosaurs , which include dromaeosaurids and troodontids . Together, these form
1400-452: The same biological name "Aves", which is a problem. The authors proposed to reserve the term Aves only for the crown group consisting of the last common ancestor of all living birds and all of its descendants, which corresponds to meaning number 4 below. They assigned other names to the other groups. Lizards & snakes Turtles Crocodiles Birds Under the fourth definition Archaeopteryx , traditionally considered one of
1440-545: The second toe which may have been held clear of the ground in life, and long feathers or "hind wings" covering the hind limbs and feet, which may have been used in aerial maneuvering. Avialans diversified into a wide variety of forms during the Cretaceous period. Many groups retained primitive characteristics , such as clawed wings and teeth, though the latter were lost independently in a number of avialan groups, including modern birds (Aves). Increasingly stiff tails (especially
1480-404: The terms warm-blooded and cold-blooded have been deprecated in the scientific field. In general, warm-bloodedness refers to three separate categories of thermoregulation . A significant proportion of creatures commonly referred to as "warm-blooded," like birds and mammals, exhibit all three of these categories (i.e., they are endothermic, homeothermic, and tachymetabolic). However, over
1520-555: The three aforementioned terms, along with their counterparts (ectothermy, poikilothermy, and bradymetabolism), thus creating a broad spectrum of body temperature types. Some fish have warm-blooded characteristics, such as the opah . Swordfish and some sharks have circulatory mechanisms that keep their brains and eyes above ambient temperatures and thus increase their ability to detect and react to prey . Tunas and some sharks have similar mechanisms in their muscles, improving their stamina when swimming at high speed. Body heat
1560-625: The west coast of Haiti. The species inhabits a variety of landscapes including humid and dry broadleaf forests, Hispaniolan pine forests dominated by Pinus occidentalis , semi-arid scrubland , and thorn forest . It also occurs in mangrove forest and occasionally in orchards and plantations. In all habitats it favors dense undergrowth. In elevation it is most numerous between about 400 and 800 m (1,300 and 2,600 ft) but occurs as high as 1,770 m (5,800 ft) in Sierra de Bahoruco of southwestern Dominican Republic. The Antillean piculet
1600-461: Was developed by Francis Willughby and John Ray in their 1676 volume Ornithologiae . Carl Linnaeus modified that work in 1758 to devise the taxonomic classification system currently in use. Birds are categorised as the biological class Aves in Linnaean taxonomy . Phylogenetic taxonomy places Aves in the clade Theropoda as an infraclass or a subclass, more recently a subclass. Aves and
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