73 Artificial incubation of resplendent quetzal (Pharomachrus mocinno mocinno) eggs

Abstract

The scientific literature lacks information regarding the incubation conditions and hatching success of the resplendent quetzal (Pharomachrus mocinno mocinno). Jesús Estudillo López, founder of the El Nido aviary, was the first to succeed with quetzal reproduction in captivity. Quetzals do not typically reproduce in captivity and the aim of this study was to increase fecundity through artificial incubation. Over a 3-year period (Yr1, Yr2, and Yr3), data about quetzal eggs, artificial incubation, and diet were recorded for 3 quetzal pairs (ranging from ~4-12 years old, with females ~4-8 years old). Eggs were manually collected from artificial nests and egg substitution was utilised. Quetzals can continue laying eggs up to 8 times with egg substitution. Eggs were weighed and placed into an 80W incubator (INCA 200®, DMP Engineering, Tel Aviv, Israel) with an automatic egg turner. The eggs were incubated for 17 to 18 days at 37.2 to 37.6°C with a relative humidity of 20 to 40%. Fisher’s exact test (2-tailed, α=0.05) was used for statistical analyses comparing the numbers of eggs hatched, infertile eggs, and eggs experiencing embryonic death for the study period. Eggs were candled on Day 3 to determine fertility by the presence of a darker area with vasculogenesis. Hatchability (%) was determined by dividing the total number of offspring hatched by the total number of eggs deemed fertile after candling. All of the eggs that did not hatch were opened at the end of the incubation period to detect early embryo death. A total of 27 quetzal eggs [mean weight (g)=17.3, s.d.=1.2] were incubated over 3 years, of which 10 (~37%) hatched, with 3 (30%) fledging and surviving to adulthood. Six of the eggs (~22%) suffered embryonic mortality during incubation, whereas 11 eggs were infertile (~41%). Hatchability over the study period was 62.5% (10/16). During Yr1 and Yr2 two eggs hatched each year, and compared with the 6 eggs that hatched in Yr3, a noteworthy but not significant difference was observed (Yr1v. Yr2, P=1; Yr1v. Yr3, P=0.188; Yr2v. Yr3, P=0.170). Embryonic death of the eggs was also not significantly different between the years (Yr1v. Yr2, P=1; Yr1v. Yr3, P=0.314; Yr2v. Yr3, P=0.303). However, the number of infertile eggs was significantly different between Yr1v. Yr3 (P=0.007) and Yr2v. Yr3 (P=0.003), but not Yr1v. Yr2 (P=1). During Yr1 and Yr2 the diet consisted of fruit (aguacatillo, banana, and papaya) and a mouse pup once a week. In Yr3 the diet was modified to include blueberry and a commercial food for Tucans (Mazuri®; https://www.mazuri.com/) and a new quetzal pair was added. The modified diet will continue to be used given that there were fewer infertile eggs. However, future research will need to be conducted to elucidate which variables specifically contribute to better hatching results. The results of this study demonstrate an assisted reproductive technique for quetzals that can benefit conservation efforts for this species.