Kepler (1972) proposed six factors related to population regulation in Puerto Rican Tody: food supply, climate, predation, territoriality, availability of nesting banks, and competition. Habitat, classified as rainforest or dry scrub, largely influences which factors are most important for regulating the population.
The tody may be somewhat resilient to severe weather events. After Hurricane Hugo, Puerto Rican Todies were one of the few insectivores that had higher population counts post-hurricane, although population counts quickly returned to prehurricane levels (Waide 1991).
A long-term mist-netting study in Guánica, Puerto Rico, captured Puerto Rican Todies during the first two weeks of January every year from 1989-2013 using 9 netlines. Survivorship estimates (using program MARK) suggest that annual survival for birds banded in January is 63.23% ± 0.59% (J. Faaborg, unpublished data). The best model representing survivorship was time-dependent with a significant positive linear increase in survival over time. The best sub-model for capture rate suggested a significant decrease in capture rate with increasing total rainfall in the first six months of the preceding year.
The longest recorded lifespan also was from the long-term mist netting study. The bird was banded in February 1974 and recaptured 4 other times, with the last record in January 1988 (Faaborg and Arendt 1989). The bird lived 13 years 11 months between banding and last capture, yielding an estimated age of 14 years, 6 months (Faaborg and Arendt 1989).