"Galapagos plumology"(PDF). darwinfoundation.org. Charles Darwin Collections Database by the Charles Darwin Foundation. Archived from the original on 17 March 2016. Retrieved 24 April 2015.
"Galapagos plumology"(PDF). darwinfoundation.org. Charles Darwin Collections Database by the Charles Darwin Foundation. Archived from the original on 17 March 2016. Retrieved 24 April 2015.