^ 3.03.13.2Andy Swash and Rob Still, Birds, Mammals and Reptiles of the Galápagos Islands, 2nd Edition, Christopher Helm, 2005, p. 86. ISBN 978-0-7136-7551-1.
^Isabel Castro and Antonia Phillips, A Guide to The Birds of the Galápagos Islands, Prinston University Press, 1996, p.113. ISBN 0-691-01225-3.