Elzanowski, Andrzej; Brett-Surman, Michael K. (July 1995). "Avian Premaxilla and Tarsometatarsus from the Uppermost Cretaceous of Montana". The Auk. 112 (3): 762–67. JSTOR4088693.
https://www.researchgate.net/publication/338355119_First_report_of_immature_feathers_in_juvenile_enantiornithines_from_the_Early_Cretaceous_Jehol_avifauna; "These feather traces and the plumage in HPG-15-1 strongly suggest that members of the Enantiornithes were born fully fledged and capable of flight soon after hatching, somewhat resembling the super-precocial megapodes, the only group of neornithines in which neonates are similarly born fledged and capable of flight (Zhou and Zhang, 2004; Jones and Göth, 2008; Xing et al., 2017). Megapodes do not fly immediately, requiring nearly two days to dig themselves out of their mounds during which they preen off their feather sheaths and let their feathers dry (Jones and Göth, 2008). Similarly, hatchling enantiornithines would have had to wait until their feather sheaths were removed and their feathers dry before attempting flight. Although ecological and behavioural differences exist between enantiornithines and megapodes (e.g., enantiornithines were arboreal and not mound-nesters), megapodes represent the precocial extreme in extant neornithines and thus the closest analogue for enantiornithine development, for which all evidence indicates a form of extreme precociality (Elzanowski, 1981; Zhou and Zhang, 2004; Xing et al., 2017). "
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Hopcraft, J.G.C.; Sinclair, A.; Holdo, R.M.; Mwangomo, E.; Mduma, S.; Thirgood, S.; Borner, M.; Fryxell, J.M.; Olff, H. (2013). "Why are wildebeest the most abundant herbivore in the Serengeti ecosystem?"(PDF). Serengeti IV: Sustaining Biodiversity in a Coupled Human – Natural System. Chicago: University of Chicago Press. Archived from the original(PDF) on 2011-12-07.
Hopcraft, J.G.C.; Sinclair, A.; Holdo, R.M.; Mwangomo, E.; Mduma, S.; Thirgood, S.; Borner, M.; Fryxell, J.M.; Olff, H. (2013). "Why are wildebeest the most abundant herbivore in the Serengeti ecosystem?"(PDF). Serengeti IV: Sustaining Biodiversity in a Coupled Human – Natural System. Chicago: University of Chicago Press. Archived from the original(PDF) on 2011-12-07.
