Demography and Populations

There appears to be no information on the age at first breeding, life span, diseases and body parasites, or population regulation in Rose-throated Becards.

Population status and density. Little is known on population structure, apart from density or abundance in two populations and point count observations in one other. Where they occur, ratings of the relative abundance range from "casual" (Slud 1960) or "rare" (e.g., Flesch 2008; transect surveys in riparian habitat) to "common" (e.g., Sutton and Pettingill 1942).

Gehlbach (1987) recorded a density of 4.2 ± 1.2 (SD) adults per 8 ha along the Rio Corona, in south-central Tamaulipas near Ciudad Victoria. In Oaxaca, Forcey (2002) described densities “as sometimes high, with counts [index of abundance] of from four to 16 birds per day not uncommon.” Point counts in coffee plantations in Chiapas recorded 0.06-0.08 birds per point (n = 195 points) (Greenberg et al. 1997). In a single mist-netting sample on a cattle ranch in Guatemala, only 2 becards were captured in 446 net-hrs (Siegel and Centeno 1996).

Estimated annual survival. Information on demography is unavailable from traditional studies of color-marked populations, or mark-release-recapture studies. Ricklefs et al. (2011) provided an estimate of annual survival based on age ratios in museum collections, which assumes that sampled population sizes and associated age distributions are in dynamic equilibrium. Female annual survival (adult and immature females, using immature males to estimate the number of immature females) was 0.327±0.091 (SE) and male survival was 0.621 ± 0.029. Because collecting bias was high in favor of males, estimated female survival may be closer to the true value in this species.

Dispersal. There is no information on dispersal of young birds from natal areas. See Nonbreeding range and migration (under Distribution) for information on adult dispersal and post-breeding movements.