SPECIES

Slate-throated Redstart Myioborus miniatus Scientific name definitions

William D. Harrod and Ronald L. Mumme
Version: 2.0 — Published July 29, 2022

Demography and Populations

Introduction

The most complete data on demography and population dynamics come from a five-year study of a color-banded population in Monteverde, Costa Rica (8, 36).

Measures of Breeding Activity

Detailed data on nest success are available from Costa Rica and Venezuela (8, 47). Reported rates of nest success differ dramatically between between the two sites; only 15% of nests in Venezuela were successful, compared to 40% in Costa Rica. Overall daily nest mortality rates (includes all forms of nest failure) were 0.065 in Venezuela and 0.032 in Costa Rica. Nestling predation rates (predator-related nest failure) in Venezuela increased with nestling age, and the overall daily nest predation rate was 0.053; in Costa Rica, predation accounted for 83% of all nest failures (8, 47).

Age at First Breeding

In Costa Rica, both males and females can nest successfully as one-year-olds in their second calendar year, but many one-year-old males may be unpaired territory holders or non-territorial floaters (36).

Clutch Size and Number of Clutches per Season

Mean clutch size varies geographically, from 2.9 in Monteverde, Costa Rica (8) to 2.1 in Yacambú National Park, Venezuela (47), and 2.4 in Henri Pittier National Park, Venezuela (51; see Eggs). In Costa Rica, females regularly lay a second clutch, and rarely a third clutch, if their initial nesting attempts fail (8).

Annual and Lifetime Reproductive Success

Because of the relatively small clutch sizes, high nest predation, and low incidence of double brooding in Costa Rica, estimated annual fecundity (1.8 fledglings per female) is considerably lower than that of temperate zone Parulidae (36).

Number of Broods Normally Reared per Season

Nearly all breeding pairs raise only a single successful brood each year, but one instance of successful double brooding has been documented in Costa Rica (8).

Proportion of Total Females that Rear ≥ One Brood to Nest-Leaving

Less than 1% (8).

Life Span and Survivorship

Based on a five-year study in Monteverde, Costa Rica, annual survival was estimated to be 0.56 for males and 0.43 for females, but these values may be unrepresentative and uncharacteristically low, possibly due to human disturbance at the study site (36); annual survival at Yacambú National Park in Venezuela is considerably higher, 0.79 (52). Because of the lower rate of female survival observed in Monteverde, the population sex ratio was male-biased, with both unpaired territorial males and unpaired non-territorial male floaters present at least some years (36).

First-year survival for fledged young in Monteverde was estimated to be 0.29, but this is almost certainly an underestimate because of undetected long-distance dispersal out of the study area, particularly by females (36; see Movements).

Disease and Body Parasites

Body Parasites

Birds from south-central Costa Rica (subspecies aurantiacus) are host to a recently described species of chewing feather lice, Myrsidea myiobori (53). Slate-throated Redstart from Colombia and Peru host lice in the genera Myrsidea, Menacanthus, and Ricinus (54). The protozoan blood parasite Haemoproteus sp. was recorded from 1 of 7 individuals sampled from the highlands of central Mexico (55).

Disease

Information needed.

Causes of Mortality

Information needed.

Population Spatial Metrics

Over most of its broad geographic range, it is generally permanently territorial and typically remains paired throughout the year (4), although unpaired territorial males and non-territorial male floaters occur in at least some populations (see Demography and Populations). During winter at high latitudes (e.g., northern Mexico) or during bad weather at high-elevation tropical locations, individuals may temporarily abandon their territories and move to lower elevations (35, 5, 27; see Movements and Migration). There are no data available on territory size or home range.

Population Status

Populations are thought to be declining (56), but no data are available on population sizes or trends.

Population Regulation

Information needed.

Recommended Citation

Harrod, W. D. and R. L. Mumme (2022). Slate-throated Redstart (Myioborus miniatus), version 2.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.sltred.02