Azores Açores (Portuguese)
Autonomous Region of Portugal and outermost region of the European Union
Autonomous Region of the Azores Região Autónoma dos Açores (Portuguese)
Flag Coat of arms
Motto:  Antes morrer livres que em paz sujeitos[1] (English: "Rather die free than subjected in peace")
Anthem: Hino dos Açores (English: "Anthem of the Azores")
Location of the Azores within the European Union
Country	Portugal
Settlement	1432
Autonomous status	30 April 1976
Named for	Açor (English: Northern goshawk)
Capitals	Ponta Delgada (executive) Angra do Heroísmo (judicial) Horta (legislative) 38°40′N 28°04′W / 38.66°N 28.07°W / 38.66; -28.07
Largest city	Ponta Delgada
Official languages	Portuguese
Demonym(s)	Açoriano(a) (English: Azorean)
Government	Autonomous Region
• Representative of the Republic	Pedro Manuel dos Reis Alves Catarino
• President of the Legislative Assembly	Luís Garcia
• President of the Regional Government	José Manuel Bolieiro
• Vice-President of the Regional Government	Artur Lima
Legislature	Legislative Assembly
National and European representation
• Assembly of the Republic	5 MPs (of 230)
• European Parliament	1 MEP (of 21 Portuguese seats)
Area
• Total	2,351 km2 (908 sq mi)
Highest elevation (Mount Pico)	2,351 m (7,713 ft)
Lowest elevation (Atlantic Ocean)	0 m (0 ft)
Population
• Census	236,440[2]
• Density	110/km2 (284.9/sq mi)
GDP (PPP)	2017 estimate
• Total	€4.128 billion[3]
• Per capita	€16,900
Currency	Euro (€) (EUR)
Time zone	UTC−01:00
• Summer (DST)	UTC±00:00
Date format	dd/mm/yyyy (CE)
Driving side	right
Calling code	+351 (292)
Postal code	95nn-99nn
ISO 3166 code	PT-20
Internet TLD	.pt
Usual abbreviation	RAA
Website	azores.gov.pt

The Azores (/əˈzɔːrz/ ə-ZORZ, US also /ˈeɪzɔːrz/, AY-zorz;^[4][5] Portuguese: Açores, Portuguese pronunciation: [ɐˈsoɾɨʃ]), officially the Autonomous Region of the Azores (Região Autónoma dos Açores), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atlantic Ocean, about 1,400 km (870 mi) west of Lisbon, about 1,500 km (930 mi) northwest of Morocco, and about 1,930 km (1,200 mi) southeast of Newfoundland, Canada.

Its main industries are agriculture, dairy farming, livestock, fishing, and tourism, which has become a major service activity in the region. In the 20th century and to some extent into the 21st, they have served as a waypoint for refueling aircraft flying between Europe and North America. The government of the Azores employs a large percentage of the population directly or indirectly in the service and tertiary sectors. The largest city of the Azores is Ponta Delgada. The culture, dialect, cuisine, and traditions of the Azorean islands vary considerably, because these remote islands were settled sporadically over a span of two centuries.

There are nine major Azorean islands and an islet cluster, in three main groups. These are Flores and Corvo, to the west; Graciosa, Terceira, São Jorge, Pico, and Faial in the centre; and São Miguel, Santa Maria, and the Formigas islets to the east. They extend for more than 600 km (370 mi) and lie in a northwest–southeast direction. All of the islands have volcanic origins, although some, such as Santa Maria, have had no recorded activity in the time since the islands were settled several centuries ago. Mount Pico, on the island of Pico, is the highest point in Portugal, at 2,351 m (7,713 ft). If measured from their base at the bottom of the ocean to their peaks, the Azores are among the tallest mountains on the planet.

The Azores are located at the seismically active Azores Triple Junction plate boundary where the North American Plate, Eurasian Plate and Nubian Plate meet.^[6]

The climate of the Azores is very mild for such a northerly location, being influenced by its distance from the continents and by the passing Gulf Stream. Because of the marine influence, temperatures remain mild year-round. Daytime temperatures normally fluctuate between 16 and 25 °C (61 and 77 °F) depending on season.^[7][8] Temperatures above 30 °C (86 °F) or below 3 °C (37 °F) are unknown in the major population centres. It is also generally wet and cloudy.

History

A small number of alleged hypogea (underground structures carved into rocks) have been identified on the islands of Corvo, Santa Maria, and Terceira by Portuguese archaeologist Nuno Ribeiro, who speculated that they might date back 2,000 years, implying a human presence on the island before the Portuguese.^[9] These structures have been used by settlers in the Azores to store grain and the suggestion by Ribeiro that they might be burial sites is unconfirmed. Detailed examination and dating to authenticate the validity of these speculations is lacking; thus it is unclear whether these structures are natural or human-made and whether they predate the 15th century Portuguese colonization of the Azores.^[10]

According to a 2015 paper published in Journal of Evolutionary Biology, research based on mouse mitochondrial DNA points to a Scandinavian rather than Portuguese origin of the local mouse population.^[11][12] A 2021 paper published in Proceedings of the National Academy of Sciences, using data from lake sediment core sampling, suggests brush-clearing was undertaken and animal husbandry introduced between 700 and 850 A.D.^[13] These findings suggest a brief period of Norse settlement, and the 2021 paper further cites climate simulations that suggest the dominant winds in the North Atlantic Ocean in that period blew from the northeast, which would have taken Viking ships heading southwest from Scandinavia more or less directly to the Azores.^[14]

Discovery

The islands were known to Europeans in the 14th century; parts of them appear in the Catalan Atlas, created in 1375.^{[citation needed][speculation?]} In 1427, a captain sailing for Prince Henry the Navigator, possibly Gonçalo Velho, may have rediscovered the Azores, but this is not certain. In Thomas Ashe's 1813 work A History of the Azores, the author identified a Fleming, Joshua Vander Berg of Bruges, who made landfall in the archipelago during a storm on his way to Lisbon.^[15] According to Ashe, the Portuguese explored the area and claimed it for Portugal.^[15] Other writers note the discovery of the first islands (São Miguel, Santa Maria and Terceira) by sailors in the service of Henry the Navigator, although there are few documents to support such claims.^[16]

Although it is commonly said that the archipelago received its name from açor (Portuguese for goshawk, a common bird at the time of discovery) it is unlikely that the bird ever nested or hunted on the islands.^[17] There were no large animals on Santa Maria; after its discovery and before settlement began, sheep were let loose on the island to supply future settlers with food.

Early settlement

The archipelago was largely settled from mainland Portugal, but settlement did not take place right away. Gonçalo Velho Cabral gathered resources and settlers for the next three years (1433–1436) and sailed to establish colonies, first on Santa Maria and then on São Miguel. Settlers built houses, established villages and cleared bush and rocks to plant crops, grain, grapevines, sugar cane and other plants suitable for local use and for export. They brought domesticated animals, such as chickens, rabbits, cattle, sheep, goats and pigs. The settlement of the unoccupied islands started in 1439 with people mainly from the continental provinces of Algarve and Alentejo, in mainland Portugal. São Miguel was first settled in 1449, the settlers – mainly from the Estremadura, Alto Alentejo and Algarve areas of mainland Portugal – under the command of Gonçalo Velho Cabral, who landed at the site of modern-day Povoação.

Flemish settlers

The first reference to the island of São Jorge was made in 1439, but the date of discovery is unknown. In 1443, the island was already inhabited, but settlement began only after the arrival of the noble Flemish native Willem van der Haegen. Arriving at Topo, São Jorge, where he lived and died, he became known as Guilherme da Silveira to the islanders. João Vaz Corte-Real received the captaincy of the island in 1483. Velas became a town before the end of the 15th century. By 1490, there were 2,000 Flemings living on the islands of Terceira, Pico, Faial, São Jorge and Flores. Because there was such a large Flemish settlement, the Azores became known as the Flemish Islands or the Isles of Flanders.

Prince Henry the Navigator was responsible for this Flemish settlement. His sister, Isabel, was married to Philip the Good, Duke of Burgundy, Flanders, at the time belonging to Burgundy. There was a revolt against Philip's rule, and disease and hunger became rampant. Isabel appealed to Henry to allow some of the unruly Flemings to settle in the Azores. He granted this and supplied them with means of transport and goods.

The 1522 earthquake and recovery

In 1522, Vila Franca do Campo, then the capital of São Miguel, was devastated by an earthquake and landslide that killed about 5,000 people, and the capital was moved to Ponta Delgada. The town of Vila Franca do Campo was rebuilt on the original site, and today is a thriving fishing and yachting port. Ponta Delgada received its city status in 1546. From the first settlement, the pioneers applied themselves to agriculture, and by the 15th century Graciosa was exporting wheat, barley, wine and brandy. The goods were sent to Terceira largely because of the proximity of that island.

Effects of the Portuguese succession crisis of 1580

Portugal fell into a dynastic crisis following the death of Cardinal-King Henry of Portugal in 1580. Of the various claimants to the crown, the most powerful was king Phillip II of Spain, who justified his rights to the Portuguese throne by the fact that his mother was a Portuguese royal princess, his maternal grandfather having been King Manuel I of Portugal.^[18] Following his proclamation in Santarém, António, Prior of Crato was acclaimed in the Azores in 1580 (through his envoy António da Costa) but was expelled from the continent by the Spaniards following the Battle of Alcântara.^[18] Yet, through the administration of Cipriano de Figueiredo, governor of Terceira (who continued to govern Terceira in the name of ill-fated, former King Sebastian of Portugal), the Azoreans resisted Spanish attempts to conquer the islands (including specifically at the Battle of Salga).^[19]

In 1583, Philip II of Spain, as King of Portugal, sent his fleet to clear the Azores of a combined multinational force of adventurers, mercenaries, volunteers, and soldiers who were attempting to establish the Azores as a staging post for a rival pretender to the Portuguese throne. Following the success of his fleet at the Battle of Ponta Delgada, captured enemies were hanged from yardarms, as they were considered pirates by Philip II. Opponents receiving the news variously portrayed Philip II as a despot or "Black Legend", the sort of insult widely made against contemporary monarchs engaged in aggressive empire building and the European wars of religion. Figueiredo and Violante do Canto helped organize a resistance on Terceira that influenced some of the response of the other islands, even as internal politics and support for Philip's faction increased on the other islands (including specifically on São Miguel, where the Gonçalvez da Câmara family supported the Spanish claimant).^[19]

English raids of 1589 and 1598

An English raid of the Azores in 1589 successfully plundered some islands and harbouring ships; eight years later, a second raid failed – the Islands Voyage.

Iberian Union

Spain held the Azores under the Iberian Union from 1580 to 1642 (called the "Babylonian captivity" in the Azores). The Azores were the last part of the Portuguese Empire to resist Philip's reign over Portugal (Macau resisted any official recognition), until the defeat of forces loyal to the Prior of Crato with the Conquest of the Azores in 1583. Portuguese control resumed with the end of the Iberian Union in 1640 and the beginning of the Portuguese Restoration War, not by the professional military, who were occupied with warfare on the Portuguese mainland, but by local people attacking a fortified Castilian garrison.

Overpopulation and emigration

In the late 16th century, the Azores and Madeira began to face problems of overpopulation. Responding to the consequent economic problems, some people of the Azores began to emigrate to the United States, Canada and Brazil.^[20]

In 1902, the Dominion Line began operating a Mediterranean passenger service between Boston and Italy via Gibraltar and the Azores, with an established port of call at Sao Miguel. In 1904, the service was taken over by the White Star Line, future owners of the ill-fated Titanic. Four ships formerly owned by Dominion were renamed and put into service under White Star, named Canopic, Romanic, Cretic and Republic, the latter of which is best known for its 1909 sinking off the New England coast. Canopic and Romanic provided regular services to Boston, while Cretic and Republic operated on the service to both New York and Boston throughout their careers. By the time the service ended in 1921, these four ships had transported an estimated total of 58,000 Azorean Portuguese to the United States.^[21]

Liberal Wars of 1828–1834

The Portuguese Civil War (1828–1834) had strong repercussions in the Azores. In 1829, in Praia da Vitória, the liberals won over the absolutists, making Terceira Island the main headquarters of the new Portuguese regime and also where the Council of Regency (Conselho de Regência) of Maria II of Portugal was established. Beginning in 1868, Portugal issued its stamps overprinted with "AÇORES" for use in the islands. Between 1892 and 1906, it also issued separate stamps for the three administrative districts of the time.

Arbitrary district divisions 1836–1976

From 1836 to 1976, the archipelago was divided into three districts, equivalent (except in area) to those in the Portuguese mainland. The division was arbitrary and did not follow the natural island groups, rather reflecting the location of each district capital on the three main cities (none of which were on the western group).

• Angra do Heroísmo consisted of Terceira, São Jorge, and Graciosa, with the capital at Angra do Heroísmo on Terceira.
• Horta consisted of Pico, Faial, Flores, and Corvo, with the capital at Horta on Faial.
• Ponta Delgada consisted of São Miguel and Santa Maria, with the capital at Ponta Delgada on São Miguel.

Modern period

In 1931, the Azores (together with Madeira and Portuguese Guinea) revolted against the Ditadura Nacional and were held briefly by rebel military.^[22]

In 1943, during World War II, the Portuguese ruler António de Oliveira Salazar leased air and naval bases in the Azores to Great Britain.^[23] The occupation of these facilities in October 1943 was codenamed Operation Alacrity by the British.^[24] This was a key turning point in the Battle of the Atlantic, enabling the Royal Air Force, the U.S. Army Air Forces, and the U.S. Navy to provide aerial coverage in the Mid-Atlantic gap. This helped them to protect convoys and to hunt hostile German U-boats.

In 1944, the U.S. constructed a small and short-lived air base on the island of Santa Maria. In 1945, a new base was constructed on the island of Terceira, named Lajes Field. This air base is in an area called Lajes, a broad, flat sea terrace that had been a large farm. Lajes Field is a plateau rising out of the sea on the northeast corner of the island. This air base is a joint American and Portuguese venture. Lajes Field continues to support the American and Portuguese Armed Forces.

During the Cold War, U.S. Navy P-3 Orion anti-submarine warfare squadrons patrolled the North Atlantic Ocean for Soviet Navy submarines and surface warships. Since its opening, Lajes Field has been used for refuelling American cargo planes bound for Europe, Africa, and the Middle East. The U.S. Navy keeps a small squadron of its ships at the harbor of Praia da Vitória, three km (1.9 mi) southeast of Lajes Field. The airfield also has a small commercial terminal handling scheduled and chartered passenger flights from the other islands in the Azores, Europe, Africa, and North America.

Following the Carnation Revolution of 1974, which deposed the Estado Novo dictatorship in Lisbon, Portugal and its territories across the world entered into a period of great political uncertainty. The Azorean Liberation Front attempted to take advantage of this instability immediately after the revolution, hoping to establish an independent Azores, until operations ceased in 1975.

In 1976, the Azores became the Autonomous Region of the Azores (Região Autónoma dos Açores), one of the autonomous regions of Portugal, and the subdistricts of the Azores were eliminated. In 2003, the Azores saw international attention when United States President George W. Bush, British Prime Minister Tony Blair, Spanish Prime Minister José María Aznar, and Portuguese Prime Minister José Manuel Durão Barroso held a summit there days before the commencement of the Iraq War.^[25]

Geography

Surface areas of the Azores Islands

Island	Area
	km2	sq mi
São Miguel	759	293
Pico	446	172
Terceira	403	156
São Jorge	246	95
Faial	173	67
Flores	143	55
Santa Maria	97	37
Graciosa	62	24
Corvo	17	7

The archipelago of the Azores is located in the middle of the northern hemisphere of the Atlantic Ocean and extends along a west-northwest to east-southeast orientation (between 36.5°–40° North latitudes and 24.5°–31.5° West longitudes) in an area approximately 600 km (373 mi) wide. The islands of the Azores emerged from what is called the Azores Plateau, a 5.8 million km² region that is morphologically accented by a depth of 2,000 m (6,600 ft).^[26][27]

The nine islands that compose the archipelago occupy a surface area of 2,346 km² (906 sq mi), that includes both the main islands and many islets located in their vicinities. They range in surface area from the largest, São Miguel, at 759 km² (293 sq mi) to the smallest, Corvo, at approximately 17 km² (7 sq mi).

Each of the islands has its own distinct geomorphological characteristics that make them unique:

• Corvo (the smallest island) is a crater of a major Plinian eruption
• Flores (its neighbor on the North American Plate) is a rugged island carved by many valleys and escarpments
• Faial is characterized for its shield volcano and caldera (Caldeira Volcano)
• Pico, is the highest point, at 2,351 m (7,713 ft), in the Azores and continental Portugal
• Graciosa is known for its active Furnas do Enxofre and mixture of volcanic cones and plains
• São Jorge is a long slender island, formed from fissural eruptions over thousands of years
• Terceira, almost circular, is the location of one of the largest craters in the region
• São Miguel is the largest island and is pitted with many large craters and fields of spatter cones
• Santa Maria – the oldest island – is heavily eroded, being one of the few places to encounter brown sandy beaches in the archipelago.

The Lagoa das Sete Cidades, located within the Sete Cidades Massif, in Sete Cidades, São Miguel Island.

These islands can be divided into three recognizable groups located on the Azores Plateau:

• The Eastern Group (Grupo Oriental) of São Miguel, Santa Maria and Formigas Islets
• The Central Group (Grupo Central) of Terceira, Graciosa, São Jorge, Pico and Faial
• The Western Group (Grupo Ocidental) of Flores and Corvo.

São Jorge, Pico and Faial are also collectively called Ilhas do Triângulo (‘Islands of the Triangle’).

Several sub-surface reefs (particularly the Dollabarat on the fringe of the Formigas), banks (specifically the Princess Alice Bank and D. João de Castro Bank), as well as many hydrothermal vents and sea-mounts are monitored by the regional authorities, owing to the complex geotectonic and socioeconomic significance within the economic exclusion zone of the archipelago.

Geology

From a geostructural perspective, the Azores are located above an active triple junction between three of the world's major tectonic plates (the North American Plate, the Eurasian Plate and the African Plate),^[27] a condition that has translated into the existence of many faults and fractures in this region of the Atlantic.^[28] The westernmost islands of the archipelago (Corvo and Flores) are located on the North American Plate, while the remaining islands are located within the boundary that divides the Eurasian and African plates.^[29]

The principal tectonic structures that exist in the region of the Azores are the Mid-Atlantic Ridge, the Terceira Rift, the Azores Fracture Zone and the Glória Fault.^[27] The Mid-Atlantic Ridge is the main frontier between the North American Plate and the African-Eurasian Plates that crosses the Azores Plateau between the islands of Flores and Faial from north to south then to the southwest; it is an extensive form crossed by many transform faults running perpendicular to its north–south orientation, that is seismically active and susceptible to volcanism.

Mountains

The Azores features a series of prominent peaks, with Montanha do Pico (also known as "Mount Pico") standing as the highest at 2,351 meters on Pico Island.^[30][31] Other notable elevations include Pico da Vara on São Miguel Island, Pico da Esperança on São Jorge Island, Cabeço Gordo on Faial Island, and Calderia de Santa Barbara on Terceira Island.^[31]

Rift and fault geology

The Terceira Rift is a system of fractures that extends from the Mid-Atlantic Ridge to the Glória Fault that represents the main frontier between the Eurasian and African Plates. It is defined by a line of submarine volcanoes and island mounts that extend northwest to southeast for about 550 km (342 mi), from the area west of Graciosa until the islets of the Formigas, that includes the islands of Graciosa, Terceira and São Miguel. Its northwest limit connects to the Mid-Atlantic Ridge, while the southeast section intersects the Gloria Fault southeast of the island of Santa Maria.

The Azores Fracture Zone extends from the Glória Fault and encompasses a relatively inactive area to the south of the islands of the Central and Eastern groups north to the Terceira Rift, along a 45° angle. The Glória Fault, for its part, extends 800 km (497 mi) along a linear line from the Azores to the Azores–Gibraltar Transform Fault.^[32]

Volcanoes

The islands' volcanism is associated with the rifting along the Azores Triple Junction; the spread of the crust along the existing faults and fractures has produced many of the active volcanic and seismic events,^[33] while supported by buoyant upwelling in the deeper mantle, some associate with an Azores hotspot.^[34] Most of the volcanic activity has centered, primarily, along the Terceira Rift.^[29]

From the beginning of the islands' settlement, around the 15th century, there have been 28 registered volcanic eruptions (15 terrestrial and 13 submarine). The last significant volcanic eruption, the Capelinhos volcano (Vulcão dos Capelinhos), occurred off the coast of the island of Faial in 1957; the most recent volcanic activity occurred in the seamounts and submarine volcanoes off the coast of Serreta and in the Pico-São Jorge Channel.^[35]

The islands have many examples of volcano-built geomorphology including caves and lava tubes (such as the Gruta das Torres, Algar do Carvão, Gruta do Natal, Gruta das Cinco Ribeiras), the coastal lava fields (like the coast of Feteiras, Faial, the Mistério of Prainha or São João on Pico Island) in addition to the inactive cones in central São Miguel Island, the aforementioned Capelinhos on Faial, the volcanic complexes of Terceira or Plinian caldeira of Corvo Island. The islands of the archipelago were formed through volcanic and seismic activity during the Neogene Period; the first embryonic surfaces started to appear in the waters of Santa Maria during the Miocene epoch (from circa 8 million years ago).

The sequence of the island formation has been generally characterized as: Santa Maria (8.12 Ma), São Miguel (4.1 Ma), Terceira (3.52 Ma), Graciosa (2.5 Ma), Flores (2.16 Ma), Faial (0.7 Ma), São Jorge (0.55 Ma), Corvo (0.7 Ma) and the youngest, Pico (0.27 Ma).^[36] All islands have experienced volcanism during their geological history, with Late Holocene volcanism being recorded from Flores^[37] and Faial.^[38] Within recorded "human settlement" history the islands of Santa Maria, Graciosa, Flores, and Corvo have not experienced any volcanic eruptions; in addition to active fumaroles and hot-springs, the remaining islands have had sporadic eruptions since the 14th century. Apart from the Capelinhos volcano in 1957–1958, the last recorded instance of "island formation" occurred off the coast of São Miguel, when the island of Sabrina was briefly formed.

Earthquakes

Owing to its geodynamic environment, the region has been a center of intense seismic activity, particularly along its tectonic boundaries on the Mid-Atlantic Ridge and Terceira Rift. Seismic events although frequent, are usually tectonic or vulco-tectonic in nature, but in general are of low to medium intensities, occasionally punctuated by events of level 5 or greater on the Richter magnitude scale.^[39][40] The most severe earthquake was registered in 1757, near Calheta on the island of São Jorge, which exceeded 7 on the Richter magnitude scale.

In comparison, the 1522 earthquake that was mentioned by historian Gaspar Frutuoso measured 6.8, but its effects were judged to be X (Extreme) on the Mercalli intensity scale,^[41] and was responsible for the destruction of Vila Franca do Campo and landslides that may have killed more than 5,000 of the inhabitants.

Usual biome of the islands. A mix of laurisilva, introduced Cryptomeria forests and agricultural fields, with usually small populated centers in between. Photo from Furnas, São Miguel Island

Biome

The archipelago lies in the Palearctic realm and has a unique biotic community that includes the Macaronesian subtropical laurissilva, with many endemic species of plants and animals.^[42][43] There are at least 6,112 terrestrial species, of which about 411 are endemic. The majority (75%) of these endemics are animals, mostly arthropods and mollusks. New species are found regularly in the Azores (e.g., 30 different new species of land snails were discovered circa 2013^[44]).

Even though the Azores look very green and sometimes wild, the vegetation has been extremely altered. A great part of it has been wiped out in the past 600 years for its valuable wood (for tools, buildings, boats, fire wood, and so on) and to clear land for agriculture. As a result, it is estimated that more than half of insects on the Graciosa island have disappeared or will become extinct.^[42]

Many cultivated places (which are traditionally dedicated to pasture or to growing taro, potatoes, maize and other crops) have now been abandoned, especially as a result of emigration. Consequently, some invasive plants have filled these deserted and disturbed lands. Hydrangeas are another potential pest, but their threat is less serious. Notwithstanding the fact that hydrangeas were introduced from America or Asia, some locals consider them a symbol of the archipelago and propagate them along roadsides. Cryptomeria, the Japanese cedar, is a conifer extensively grown for its timber. The two most common of these alien species are Pittosporum undulatum and Hedychium gardnerianum.^[45] Reforestation efforts with native laurissilva vegetation have been accomplished successfully in many parts of the Azores.^[46][47][48]

The Azores has at least two endemic living bird species. The Azores bullfinch, or Priolo, is restricted to remnant laurisilva forest in the mountains at the eastern end of São Miguel^[49] and is classified by BirdLife International as endangered. Monteiro's storm petrel, described to science as recently as 2008, is known to breed in just two locations in the islands but may occur more widely. An extinct species of owl, the São Miguel scops owl, has recently been described, which probably became extinct after human settlement because of habitat destruction and the introduction of alien species. Five species of flightless rail (Rallus spp.) once existed on the islands, as did a flightless quail (Coturnix sp.)^[50] and another species of bullfinch, the greater Azores bullfinch, but these also went extinct after human colonization. Eleven subspecies of bird are endemic to the islands.^[51] The Azores has an endemic bat, the Azores noctule, which has an unusually high frequency of diurnal flight.

The islets of the Formigas (the Portuguese word for "ants"), including the area known as the Dollabarat Reef, have a rich environment of maritime species, such as black coral and manta rays, different species of sharks, whales, and sea turtles. Seventeen new marine reserves (with special conservation status) were added to the Azorean Marine Park (which covers around 900,000 km² (350,000 sq mi)).^[52] On São Miguel there are notable micro-habitats formed by hot springs that host extremophile microorganisms.^[53]

Climate

The archipelago is spread out at roughly the same latitude as the southern half of mainland Portugal, but its location in the mid-Atlantic Ocean gives it a generally tepid, oceanic, mild to warm subtropical climate, with mild annual oscillations.

'Azores High' anticyclone

The Azores archipelago is located in a transition and confrontation zone between air masses of tropical origin and masses of cooler air of polar origin. The climate of the archipelago is largely determined by variations in the atmospheric pressure field over the North Atlantic. These variations conditioned by the mass of the American Continent and the Atlantic water mass are overlapped by a semi-permanent subtropical Atlantic anticyclone, commonly known as the Azores High. This anticyclone experiences seasonal variations which can affect the archipelago in many ways.

In winter, the Azores anticyclone is positioned further south, and allows for a descent of the Polar front, approaching it to the archipelago. In summer, on the other hand, the anticyclone's movement further north, leads to the departure of the polar front and its associated disturbances towards higher latitudes. Far enough away from the mainland coasts, the continental air masses that reach the archipelago are weakened by the maritime influence.

The same can not be said for the higher altitudes (e.g. Mount Pico), where upper air masses of a continental origin and with a more direct pathway can reach the surface and present those areas with drier air and more extreme temperatures. At the same time, this free atmosphere circulating air transports aerosols to the archipelago, namely volcanic ash or fine sands from the Sahara desert, which sporadically affect the radiation and air quality.^[54]

Daily maximum temperatures at low altitudes usually range between 16 and 25 °C (61 and 77 °F). The average annual rainfall generally increases from east to west, ranging from 700 mm (28 in) in Santa Maria to 1,600 mm (63 in) in Flores and reaching values above 5,000 mm (200 in) on the highlands of Pico.^[55]

Köppen classification

Under the Köppen climate classification, the eastern group (São Miguel and Santa Maria) is usually classified as Mediterranean while the central and western group (especially Flores and Corvo) is increasingly more humid subtropical and overall rainier because of the effects of the Gulf Stream. This stream has a large effect over the sea temperature which varies between 16 °C (61 °F) in February and March, and 23 °C (73 °F) in August and September, and increases earlier in the western group.^[56]

Salvador Rivas-Martínez data presents several different bioclimatic zones for the Azores.^[57] Seasonal lag is extreme in the low-sun half of the year, with December being milder than April in terms of mean temperatures. During summer the lag is somewhat lower, with August being the warmest month, though September is usually as warm or warmer than July.

Temperatures, humidity, and sunshine

Although temperatures as warm as 32.1 °C (89.8 °F) have been recorded on Pico, neither Ponta Delgada nor Angra do Heroísmo, the two largest cities, have ever been warmer than 30 °C (86 °F). There has never been a frost, snowfall, freeze or even temperatures below 5 °C (41 °F) recorded at sea level on any of the islands. The coldest weather in winter usually comes from northwesterly air masses originating from Labrador in Canada. However, since those air masses are warmed up as they pass across the warmer Atlantic Ocean, temperatures by day even then exceed 10 °C (50 °F).

The average relative humidity can range from 80% at the coast to over 90% above 400 m (1,300 ft). However, higher elevations above the planetary boundary layer can experience extremely low values close to 10%.^[54] Summers are especially humid in August and may increase the perceived temperature by a few degrees. Winters are not only very mild but also very humid and contribute substantially to the annual precipitation.^[58]

Insolation is relatively low, with 35-40% of the total possible value for sunshine, and higher in topographically lower islands such as Graciosa or Santa Maria, inversely proportional to precipitation. This is directly caused by the orographic lift of humid air masses and is especially pronounced in islands marked by high orography.^[54]