Hans Christian Cornelius Mortensen (27 August 1856 – 7 June 1921) was a

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

teacher A teacher, also called a schoolteacher or formally an educator, is a person who helps students to acquire knowledge, competence, or virtue, via the practice of teaching. ''Informally'' the role of teacher may be taken on by anyone (e.g. whe ...

and

ornithologist Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

. He was the first to employ

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 ...

for scientific purposes. Mortensen was born in

Jonstrup Jonstrup is a suburban neighbourhood situated in Furesø Municipality on the west side of Hareskoven forest in the northwestern outskirts of Copenhagen, Denmark. The original village has merged with the neighbouring villages of Måløv in Ballerup ...

on the island of

Zealand Zealand ( da, Sjælland ) at 7,031 km2 is the largest and most populous island in Denmark proper (thus excluding Greenland and Disko Island, which are larger in size). Zealand had a population of 2,319,705 on 1 January 2020. It is the 1 ...

, Denmark. After completing secondary school in 1874 he began studies in first theology and later in medicine and zoology at the

University of Copenhagen The University of Copenhagen ( da, Københavns Universitet, KU) is a prestigious public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in ...

without finishing any of these studies. He then worked as a schoolteacher at different schools in the

Copenhagen Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ar ...

area before, in 1888 and despite the lack of a university degree, became a master at the

High School A secondary school describes an institution that provides secondary education and also usually includes the building where this takes place. Some secondary schools provide both '' lower secondary education'' (ages 11 to 14) and ''upper seconda ...

of Viborg in

Jutland Jutland ( da, Jylland ; german: Jütland ; ang, Ēota land ), known anciently as the Cimbric or Cimbrian Peninsula ( la, Cimbricus Chersonesus; da, den Kimbriske Halvø, links=no or ; german: Kimbrische Halbinsel, links=no), is a peninsula of ...

where he stayed for the rest of his life. From 1909 he held the post as a senior master. In 1891 he married Ingeborg Lemming (1858-1938), a fellow teacher and feminist who assisted him with his bird ringing. The couple had no children. Mortensen's first successful experiments with bird ringing took place in 1899 with

common starling The common starling or European starling (''Sturnus vulgaris''), also known simply as the starling in Great Britain and Ireland, is a medium-sized passerine bird in the starling family, Sturnidae. It is about long and has glossy black plumage ...

s. Most were caught in

nest box A nest is a structure built for certain animals to hold eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic materia ...

es with an automatic closing mechanism. Later he also ringed

white stork The white stork (''Ciconia ciconia'') is a large bird in the stork family, Ciconiidae. Its plumage is mainly white, with black on the bird's wings. Adults have long red legs and long pointed red beaks, and measure on average from beak tip to en ...

heron The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychus ...

gull Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. They are most closely related to the terns and skimmers and only distantly related to auks, and even more distantly to waders. Until the 21st century, m ...

s and various species of

duck Duck is the common name for numerous species of waterfowl in the family Anatidae. Ducks are generally smaller and shorter-necked than swans and geese, which are members of the same family. Divided among several subfamilies, they are a form t ...

. It is said that he personally ringed more than 6000 birds during his lifetime. He made most of his bird rings himself, cutting them from

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

sheet and stamping each with an address and an individual number. From 1906 he received some financial assistance from the

Carlsberg Foundation Carlsberg Foundation ( da, Carlsbergfondet) was founded by J. C. Jacobsen in 1876, by allocating some of his shares in the Carlsberg Brewery to fund and operate the Carlsberg Laboratory and the Museum of National History at Frederiksborg Palace. ...

. In 1906 he was a cofounder, with

Eiler Lehn Schiøler Eiler Lauritz Theodor Lehn Schiøler (30 October 1874 – 13 August 1929) was a Danish ornithologist and banker who came from a family of stockbrokers. He was the author of a major but incomplete multi-volume work on the birds of Denmark published ...

, of the Danish Ornithological Society. In 1909 he was made a corresponding member of the Hungarian Ornithological Society. Hans Christian C. Mortensen was a very distinctive character. As a teacher he was both feared by and popular among his students. He went on field trips with the students, something unusual at that time. He was also known as a keen

piano The piano is a stringed keyboard instrument in which the strings are struck by wooden hammers that are coated with a softer material (modern hammers are covered with dense wool felt; some early pianos used leather). It is played using a keyboa ...

and

cello The cello ( ; plural ''celli'' or ''cellos'') or violoncello ( ; ) is a Bow (music), bowed (sometimes pizzicato, plucked and occasionally col legno, hit) string instrument of the violin family. Its four strings are usually intonation (music), t ...

player.

References

* Engelstoft & Dahl (ed.): Dansk biografisk leksikon (The Danish Biography), Copenhagen 1942 * 1856 births 1921 deaths Danish ornithologists People from Furesø Municipality {{ornithologist-stub