Archaeopteryx that in an ostrich (4.2 micrometres per day). Using this range of bone growth rates, they calculated how long it would take to "grow" each specimen of "Archaeopteryx" to the observed size; it may have taken at least 970 days (there were 375 days in a Late Jurassic year) to reach an adult size of . The study also found that the avialans "Jeholornis" and "Sapeornis" grew relatively slowly, as did the dromaeosaurid "Mahakala". The avialans "Confuciusornis" and "Ichthyornis" grew relatively quickly, following a growth trend similar to that of modern birds. One of the few modern birds that exhibit
Archaeopteryx in similar feathers"). In German, this ambiguity is resolved by the term "Schwinge" which does not necessarily mean a wing used for flying. "Urschwinge" was the favoured translation of "Archaeopteryx" among German scholars in the late nineteenth century. In English, "ancient pinion" offers a rough approximation. Since then twelve specimens have been recovered: The Berlin Specimen (HMN 1880/81) was discovered in 1874 or 1875 on the Blumenberg near Eichstätt, Germany, by farmer Jakob Niemeyer. He sold this precious fossil for the money to buy a cow in 1876, to innkeeper Johann Dörr, who again sold it to Ernst Otto Häberlein,