Puerto Rican Tody excavates a curved burrow into an earth bank with a nest chamber at the end (Raffaele 1989). Excavation begins in early September although the early burrows are not used, and continues through June, with the average excavation taking 8 weeks to complete (Kepler 1972). Burrows typically have a nearly circular entrance, averaging 3.4 cm wide and 3.6 cm high, with the entrance typically placed 0.46 m above the ground in a 1.1 m tall bank (Rolle 1963, Kepler 1972). The mean length is 30.5 cm in wet forests or 26.9 cm in dry scrub, terminating in an enlarged and slightly depressed chamber for the eggs (Kepler 1972). The chamber averages 11.3 cm long, 9.8 cm wide, and 6.9 cm high (Kepler 1972). Nests excavated in areas surrounded by a moderate amount of vegetation are most successful with a 47% success rate (Kepler 1972). Male and female todies excavate their nest together, digging alternately and leaving to forage together after working (Kepler 1972). Throughout the tody range, twice as many burrows are excavated as are used; 33% of excavated burrows are used in the rain forest, and 62.5% of nests excavated in xeric shrub are used, with the most burrows abandoned due to unsuitable soil or obstacles (Kepler 1972, Raffaele 1989). Each year todies excavate a new burrow, although 89% of new burrows are within 10 meters of old burrows (Kepler 1972).
Primarily from March to July, one to four eggs are laid on the bare ground of the nest chamber (Raffaele 1989). Eggs have shiny white shells with a rosy tinge from the large orange-red yolks; egg shells are very fragile (Kepler 1972). The mean dimensions are 16.0 mm x 13.5 mm, with a mean weight of 1.43 grams (Kepler 1972). Typical egg mass for most bird species is 2-11% of the bird’s body mass, but the egg is 26% of the female’s body mass and has a high yolk content (Kepler 1972). Eggs are laid on consecutive nights starting 3-4 weeks after the nest is completed (Kepler 1972). Clutch sizes for the rain forest averaged 2.39 eggs (n = 44), whereas clutches in the xeric scrub averaged 2.22 (n = 9) (Kepler 1972). Additionally, clutches are significantly larger with helpers (mean 2.9) than without helpers (mean 2.3) (Kepler 1972). Eggs are laid to coincide with peak insect abundance for rearing nestlings. Second clutches are rarely attempted, usually only when the first is depredated (Kepler 1972).
The incubation period likely is 21-22 days, but data are sparse (Kepler 1972). Both sexes incubate, but the length of time spent incubating and time between visiting the nest for incubation is largely unpredictable; average nest visitations are 13 minutes long and a pair averages 1.8 trips every daylight hour during incubation (Kepler 1972). Time spent incubating and nest visits may occur more frequently near fledging (Kepler 1972). Generally, each adult spends less than 25% of their time incubating, or less time if a helper is present (Kepler 1972). Males and females have a "favorite perch" during incubation near the nest that they use while communicating with their mate when switching incubation duties, although todies are generally very quiet around the nest (Kepler 1972). Birds orient themselves towards light while in the burrow (Kepler 1972).
The nestling period usually is 19 to 20 days depending on the number of chicks, parental attentiveness, and the presence of helpers (Kepler 1972). The first 8 days are spent brooding the young; the chicks are altricial and have no natal down (Kepler 1972). Nestlings are silent for the first 3 days, and then develop squeaks, but are not capable of adult calls until after fledging (Kepler 1972). Chicks huddle together from about 5 to 12 days (Kepler 1972). Chicks defecate in the burrow and do not have fecal sacs that can be removed, but Kepler (1972) found no evidence of parasites on the nestling's plumage despite dirty nest conditions. Although both parents feed nestlings, females may feed nestlings more frequently than males (Merola 1995). The frequency of hourly nest visits increases steadily from hatching to fledging (Kepler 1972).
One to two additional adults, likely previous offspring from the nesting pair, sometimes assist raising nestlings, which increases the number of offspring that eventually fledge (Kepler 1972, Raffaele 1989). Helpers rarely assist with nest incubation, and help only sporadically after the chicks fledge (Kepler 1972).