The Col de Bretolet is a

mountain pass A mountain pass is a navigable route through a mountain range or over a ridge. Since many of the world's mountain ranges have presented formidable barriers to travel, passes have played a key role in trade, war, and both Human migration, human a ...

in the

Swiss Alps The Alpine region of Switzerland, conventionally referred to as the Swiss Alps (german: Schweizer Alpen, french: Alpes suisses, it, Alpi svizzere, rm, Alps svizras), represents a major natural feature of the country and is, along with the Swiss ...

in the canton of

Valais Valais ( , , ; frp, Valês; german: Wallis ), more formally the Canton of Valais,; german: Kanton Wallis; in other official Swiss languages outside Valais: it, (Canton) Vallese ; rm, (Chantun) Vallais. is one of the cantons of Switzerland, 26 ...

, close to the border between

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

and the

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

department Department may refer to: * Departmentalization, division of a larger organization into parts with specific responsibility Government and military *Department (administrative division), a geographical and administrative division within a country, ...

Haute-Savoie Haute-Savoie (; Arpitan: ''Savouè d'Amont'' or ''Hiôta-Savouè''; en, Upper Savoy) or '; it, Alta Savoia. is a department in the Auvergne-Rhône-Alpes region of Southeastern France, bordering both Switzerland and Italy. Its prefecture is ...

. It lies above the village of

Champéry Champéry (; frp, Champérié) is a municipality in the district of Monthey in the canton of Valais in Switzerland. History Champéry is first mentioned in 1286 as ''Champery'' The Hotel Dent-du-Midi opened in 1857. In 1969, Champéry becam ...

at an altitude of 1923 m

asl American Sign Language (ASL) is a natural language that serves as the predominant sign language of Deaf communities in the United States of America and most of Anglophone Canada. ASL is a complete and organized visual language that is express ...

within a 567 ha nature reserve (

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

management category IV) set aside for the protection and study of migratory

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...

s. It contains a

bird ringing Birds are a group of warm-blooded vertebrates constituting the class Aves (), 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 ...

station operated by the

Sempach Bird Observatory The Swiss Ornithological Institute () is a non-profit foundation headquartered in Sempach in the district of Sursee in the canton of Lucerne in Switzerland dedicated to the study and conservation of birds. The Swiss Ornithological Institute wa ...

(Swiss Ornithological Institute).

Bird research

The Col de Bretolet is located on a bird migration route through which many thousands of birds pass, especially from early August to late October, with many travelling at night. In 1958 a long-term bird ringing program began in order to monitor autumn migration in the Swiss Alps and study energy metabolism,

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 are distinguished from other orders of birds by t ...

moult In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...

and changes in migration patterns in relation to global

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

, as well as documenting irruptions of

jay A jay is a member of a number of species of medium-sized, usually colorful and noisy, passerine birds in the Crow family (biology), family, Corvidae. The evolutionary relationships between the jays and the magpies are rather complex. For examp ...

s, tits and

finch The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usua ...

es, comparing data with other ringing sites elsewhere and educating ringers. Birds are caught both by day and at night in

mist net Mist nets are used by hunters and poachers, but also by ornithologists and chiropterologists to capture wild birds and bats for banding or other research projects. Mist nets are typically made of nylon or polyester mesh suspended between two po ...

s as they fly through the pass. On foggy nights the birds are attracted to the nets with the use of bright lights. As well as birds,

bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most bi ...

s are caught, and the pass is also well known for the migration of

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s, notably

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

s and

hoverflies Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, whi ...

References

* * * {{cite web , url= http://www.vogelwarte.ch/home.php?lang=e&cap=projekte&subcap=vogelzug&file=../detailprojects.php&projId=580, title= Long-term surveillance of bird migration on Col de Bretolet , accessdate= 15 February 2010, website= , publisher= Swiss Ornithological Institute , date= Bretolet Bretolet Bretolet France–Switzerland border crossings Bird observatories Bird migration