Question: What did a recorder of Mockin' Bird Hill  famously pioneer?

Context paragraphs:
Fuglebakken, Frederiksberg: Fuglebakken (literally "The Bird Hill"), also known as Fuglebakkekvarteret (English: The Fuglebakke neighbourhood), is a mostly residential neighbourhood in the northern part of Frederiksberg in Copenhagen, Denmark.  The area is bounded by Godthåbsvej to the south, Nordre Fasanvej to the east, Borups Allé to the north and the S-train line on the municipal border with Copenhagen to the west.  It consists of a mixture of single family detached homes, terraced housing and apartment buildings.

Calle Jularbo: Carl Jularbo, well known as Calle Jularbo and born as "Karl Karlsson" (6 June 1893 - 13 February 1966) was the most famous Swedish accordionist of his time.  He had a very distinct personal style, that has played a significant part in forming the Swedish accordion tradition.  He was extremely productive, recording 1577 tunes and he won 158 accordion competitions.  He maintained a large repertoire without being able to read music.  His best known tune is "Livet i Finnskogarna" (roughly "Life in the Finn forests"), recorded in 1915.  This song was the basis for the Les Paul and Mary Ford hit of 1951, "Mockin' Bird Hill".

Foolow: Foolow (Old English possibly for "Bird Hill" or "Colourful Hill" ) is a village in the Derbyshire Peak District.  The population of the village is included in the civil parish of Great Hucklow

The Migil Five: The Migil Five (sometimes styled The Migil 5) were a British pop, rhythm and blues and (originally) jazz group in the early to mid-1960s, whose biggest hit was a bluebeat version of "Mockin' Bird Hill".

Conway Bridge: The Conway Bridge is a historic road bridge that crosses the Nolichucky River between Greene County and Cocke County, Tennessee.  It has also been known as Nolichucky River Bridge, as Bridge at Bird Hill, as Birds Hill Bridge and as Bridge at Conway Ferry.

Les Paul: Lester William Polsfuss (June 9, 1915 – August 12, 2009), known as Les Paul, was an American jazz, country, and blues guitarist, songwriter, luthier, and inventor.  He was one of the pioneers of the solid-body electric guitar.  Paul taught himself how to play guitar, and while he is mainly known for jazz and popular music, he had an early career in country music.  He is credited with many recording innovations.  Although he was not the first to use the technique, his early experiments with overdubbing (also known as sound on sound), delay effects such as tape delay, phasing effects and multitrack recording were among the first to attract widespread attention.

Blues Ain't No Mockin Bird: "Blues Ain't No Mocking Bird" is a short story by Toni Cade Bambara written in 1971.  It is told through the point of view of a young black girl in North America.  "Blues Ain't No Mockin Bird" is about a family whose privacy is invaded by two white cameramen who are making a film for the county's food stamp program.  In this story, the little girl is playing with her neighbors, Tyrone and Terry and cousin, Cathy at her grandmother’s house.  Her grandmother is on the back porch spreading rum on the cakes she has made.  Two white filmmakers, shooting a film ‘‘about food stamps’’ for the county, tree near their yard.  The little girl’s grandmother asks them to leave but not listening to her request, they simply move farther away.  When Granddaddy Cain returns from hunting a chicken hawk, he takes the camera from the men and smashes it.  The white men swears and goes away.  Cathy, the distant cousin of the little girl, displays a precocious ability to interpret other people’s actions and words as well as an interest in storytelling and writing.  Granny shares a story with the children and Cathy which relates to her feeling about people filming without permission.  To her, life is not to be publicized to everyone because they are not as "good" or wealthy as others.

Bird Hill: Bird Hill is a summit in Scott County in the U.S. state of Missouri with an elevation of 466 ft .

White Bird Hill Summit: White Bird Hill Summit is a mountain pass in north central Idaho on U.S. Highway 95.  Located in Idaho County, it is midway between White Bird and Grangeville.  The summit elevation of the highway is 4245 ft above sea level, through a substantial cut.

Mockin' Bird Hill: Mockin' Bird Hill is a song, written in 3/4 time, by George Vaughn Horton, and perhaps best known through recordings by Patti Page, Donna Fargo, and by Les Paul and Mary Ford in 1951.

Supporting paragraphs: Mockin' Bird Hill Les Paul
Answer: the solid-body electric guitar