David Lack based his analysis on the large collection of museum specimens collected by the 1905–06 Galápagos expedition of the California Academy of Sciences, to whom Lack dedicated his 1947 book.
David Lack baseou a súa análise na gran colección dos exemplares de museo recollidos na expedición ás Galápagos de 1905–06 da Academia de Ciencias de California, á cal Lack lle dedicou o seu libro de 1947.