The earliest recorded breeding age for adult Keel-billed Toucans is 21 months for females and 34 months for males.
Although there is information about specific parasites infecting Keel-billed Toucans, there is no information about the effect of parasites on populations of these birds. Van Tyne (1929) noted that several of the parasites (mites and bot flies) might not harm the adults but would, in sufficient numbers weaken or kill nestlings. Infection with microfilariae can have negative fitness consequences for some species of birds (Sehgal et al. 2005).
Keel-billed Toucan parasites that have been identified are as follows:
a. Feather mites - subfamily Proctophyllodinae. Van Tyne (1929) found all individuals heavily infested with these mites on the vanes of the flight feathers. However, he believed this was a problem mainly for nestlings. He also found small mites (Liponyssus sp.) on nestlings. These mites may carry encephalitis viruses (Hammon et al. 1948).
b. Chewing lice (Mallaphaga). At least three species infecting Keel-billed Toucans have been identified; Austrophilopterus subsimilis (Malcomson 1960), and Philopterus cancellosus and Myrsidea vixtrix. Van Tyne (1929) discovered three or four to more than a hundred of the latter two species on the head, throat and wings of toucans and eggs encrusting the throat feathers.
c. Ticks (Amblyomma sps). These were encountered on the bare skin of the face and throat.
d. Hippoboscid (louse) fly. Only a single specimen of Lynchia fusca was seen on one juvenal bird.
e. Other Diptera. Philornis pici (bot fly) parasitized birds under the skin of the lower neck and back (Van Tyne 1929).
a. Plasmodium sp. (Galindo and Sousau 1966) and P. rouxi (Manwell and Sessler 1971), malaria-carrying parasite.
b. Trypanosomes - microscopic unicellular protozoa, generally non-pathogenic (Greiner and Ritchie 1997).
c. Haemoproteus - (Galindo and Sousau 1966) - intracellular parasites that infect red blood cells, considered non-pathogenic (Greiner and Ritchie 1997).
d. Acanthamoeba - amoeba known to cause central nervous system infections in humans and other animals (Visvesvara et al. 2007).
Microfilariae (nematode larvae) - generally considered apathogenic (Greiner and Ritchie 1997).