The breeding season extends from February to June, comprising a 28 day incubation period and a 60 day period of nestling growth within the nest-cavity (Forshaw 1989, Renton and Salinas-Melgoza 1999, Renton 2002). Most information on Lilac-crowned Parrot reproduction comes from nest studies carried out in tropical dry forest on the coast of Jalisco (Renton and Salinas Melgoza 1999, 2004, Renton 2002).
Lilac-crowned Parrots nest in natural cavities of emergent trees, characteristic of semi-deciduous forest, such as Astronium graveolens, Piranhea mexicana, Brosimum alicastrum, and Tabebuia spp. (Renton and Salinas-Melgoza 1999, Monterrubio et al. 2009). Nest cavities occur at an average height of 10 m above the ground, with a narrow cavity entrance of 10 cm diameter, and a cavity depth ranging from 20 cm to 4.6 m (Renton and Salinas-Melgoza 1999, upubl. data). The base of the nest-cavity may be lined with wood-chips, leaves of Piranhea mexicana, or occasionally the hanging moss Tillandsia spp. (K. Renton unpubl. data).
Female Lilac-crowned Parrots have a mean clutch size of 2.6 eggs, range 1-4 eggs (Renton and Salinas-Melgoza 2004). The eggs are white and unmarked. Mean dimensions for 19 eggs were 37.6 (35.7–39.7) x 28.6 (27.5–30) mm, with a mean egg weight of 14.8 (12–18.5) g (Renton and Salinas-Melgoza 2004). There is a low 42% nest success, resulting in an average brood size of 1.8 nestlings per egg-laying female, with a reproductive output of 0.99 fledglings per egg-laying female (Renton and Salinas-Melgoza 2004). However, taking into consideration the additional loss from post-fledging mortality, the final outcome of reproductive efforts is 0.70 independent young per egg-laying pair of Lilac-crowned Parrots (Salinas-Melgoza and Renton 2007).
Inter-annual fluctuations in rainfall as a result of the El Niño-La Niña cycle in the Pacific Ocean limits food resource availability for Lilac-crowned Parrots in tropical dry forest (Renton 2001, 2002). Climatic variability in dry forest affects all aspects of Lilac-crowned Parrot reproduction including clutch size, nestling growth and survival, reproductive output of nesting pairs, and the survival and recruitment of independent young in the population (Renton 2002, Renton and Salinas-Melgoza 2004, Salinas-Melgoza and Renton 2007). This has implications for the potential impact of climate change on reproduction of wild populations of the Lilac-crowned Parrot in tropical dry forest.