While there is no known population size, the species is thought to be stable with a distribution size of 1,360,000 km2 (BirdLife International 2016). The generation time for the species is around 3.7 years (BirdLife International 2016). In a mark-recapture study done by Lopes et al. (1980), males (n=3) had a longest recapture time between 3 years and 7 months and 3 years and 11 months, meaning their natural lifespan is likely around the four-year mark. Meanwhile the female’s (n=3) longest recapture time was between 2 years and 9 months and 5 years and 5 months, with a probable life span of less than 6 years (Lopes et al. 1980). Parker et al. (1996) categorized the Ruby-crowned Tanager’s center of abundance as lower tropical.
The parasites and infectous diseases of the Ruby-crowned Tanager have been relatively well characterized. Roos (2002) noted 100% of birds sampled from the Atlantic Forest (n=7) had an ectoparasite; 57.14% had feather mites, 42.86% had lice, and 42.86% had ticks. They have relatively high levels of Amblyomma tick infestations compared to other birds, and it is thought this might be related to their propensity to occur in the lower forest strata (Luz et al. 2016). Amblyomma longirostre was found on an individual in San Rafael National Park, Paraguay (Ogrzewalska et al. 2014), and numerous larvae and nymphs of this species from individuals from São Paulo, Brazil (Labruna et al. 2007). They host the nymphs and/or larvae of Amblyomma sp., A. longirostre, A. parkeri, A. nodosum, A. cajennense, and A. aureolatum (Guglielmone et al. 2003, Arzua et al. 2005, Sanches et al. 2013, Maturano et al. 2015, Luz et al. 2016). An Ixodes fuscipes nymph was collected from a Brazilian bird (Arzua et al. 2005). They are known hosts of a Amerodectes species of feather mite (Daud et al. 2016). Along with body parasites, Ribeiro et al.’s study (2005) found 30% of individuals (n=10) have avian malaria. They are known hosts for the coccidium Isospora navarroi (do Bomfim Lopes et al. 2013). They are known hosts of the tapeworm Anonchotaenia brasiliensis (Phillips et al. 2014). Of 180 individuals examined from São Paulo, Brazil, 15 had blood parasites: 2 with Plasmodium, 2 with Trypanosoma, and 1 with a microfilaria (Bennett and Lopes 1980). Similarly, of 841 individuals examined from São Paulo State for blood parasites, 84 were infected: 5 with Haemoproteus, 2 with Plasmodium, 10 with Trypanosoma, and 68 with microfilaria (Woodworth-Lynas et al. 1989). Another study on birds from São Paulo found individuals infected with the blood parasites Haemogregarina sp., Haemoproteus sp., and Toxoplasma sp. (de Lucena 1941), and Toxoplasma antibodies have been identified in some individuals (Gennari et al. 2014). Individuals from São Paulo exhibited hemagglutination-inhibition antibodes for the arbovirus Eastern Equine Encephalitis (Lopes and Sacchetta 1974). Ruby-crowned Tanagers may be hosts to the brood parasite, the Shiny Cowbird, and raise the young as their own (Sick 1993).