Attributes / relations provided by 
♦ 1del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). 
Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona.
♦ 2Hamish Wilman, Jonathan Belmaker, Jennifer Simpson, Carolina de la Rosa, Marcelo M. Rivadeneira, and Walter Jetz. 2014. 
EltonTraits 1.0: Species-level foraging attributes of the world's birds and mammals. Ecology 95:2027
♦ 3Jetz W, Sekercioglu CH, Böhning-Gaese K (2008) 
The Worldwide Variation in Avian Clutch Size across Species and Space PLoS Biol 6(12): e303. doi:10.1371/journal.pbio.0060303
♦ 4Humphrey, PS, D. Bridge, PW Reynolds, and RT Peterson. 1970. Birds of Isla Grande (Tierra del Fuego). Preliminary Smithsonian Manual. Smithsonian Institution, Washington, DC