Biologists from Doñana National Park in Andalucia found famous songbirds existence is accurately classified as threatened by the International Union for Conservation of Nature. The DuPont Lark, a relative of the skylark, needs flat scrub land but in Spain much of this has been used for building development in Andalucia, Murcia, Castilla la Mancha and Catalonia. Only 2,000 birds are believed to exist in what remains of their natural habitat.

Because of the bird’s size, it is smaller than the skylark and due to its color of brown, population counts are extremely difficult. However, Spanish scientists in the Ebro valley of Catalonia region of Spain have a rather unique method of conducting a census poll. They use audio recording to count the range of notes in the bird’s repertoire. Using hidden microphones placed where the birds usually inhabit, they reported a total of 330 males in the area. -DuPont’s lark has a range of 12 singing sequences or phrases. It is smaller than the skylark and its brown color makes it hard to spot, so censuses are carried out by counting birds by their songs.

Paola Laiolo, who led the Spanish research team, said: "The female birds are attracted by the complexity and range of the male's song. We found that the lack of variation of notes or scales corresponded to the areas where the population of larks was smallest. The birds which lacked tutors - or other male birds to learn from - had the smallest range."

The DuPont Lark is historically immortalized by the poet Shelley in classic literature.