Setophaga Ruticilla Research Articles

SINGING BEHAVIOR VARIES WITH BREEDING STATUS OF AMERICAN REDSTARTS (SETOPHAGA RUTICILLA)

We examined the relationship between singing behavior and breeding status in the American Redstart (Setophaga ruticilla) by analyzing song rates, singing mode (Repeat or Serial), and variability of song delivery in relation to the age and breeding status of 129 males in the Hubbard Brook Experimental Forest, New Hampshire. Unpaired males spent most of their time (>90%) after dawn singing in Repeat mode, whereas paired males sang sporadically, in Serial as well as Repeat mode (51% of their singing time). Males who lost their mates sang in Repeat mode at rates indistinguishable from males who had not yet obtained a mate. Overall, unpaired males sang in Repeat mode at significantly higher and less variable rates than did paired males. Although a larger proportion of second-year males were unpaired than after-second-year males, we found no evidence that age affected singing behavior.We also assessed the effect of pairing status on male detectability in song-based monitoring surveys (e.g., point counts), and we suggest a field protocol for identifying unpaired males. Simulations of 5-min field samples, obtained from continuous samples >3 hr in duration, suggest that human listeners would be twice as likely to detect unpaired males as paired males. This result suggests that surveys based on aural detections may be biased in favor of unpaired males. In our population, >90% of males who sang >40 Repeat songs in 5 min were unpaired. Unpaired males were >3 times as likely as paired males to sing only Repeat songs in a given 5-min period. These results suggest that it may be possible to identify unpaired male American Redstarts by their high singing rates of exclusively Repeat songs.

Response of bird communities to selection harvesting in a northern tolerant hardwood forest

We investigated the responses of forest birds to habitat changes following timber harvest by selection cutting in three northern tolerant hardwood forest stands using a before–after control-impact (BACI) type of experimental design. We observed only minor effects on the bird community associated with mature forests. Ovenbird ( Seiurus aurocapilla) abundances declined by about 80–90% in two of the three harvested blocks. Black-throated blue warblers ( Dendroica caerulescens) declined in abundance by about 70% on a single block 2 and 3 years post-harvest. Mechanical disturbance of the shrub layer [primarily Canada yew ( Taxus canadensis)] was coincident to this decline. Several bird species that prefer early successional or shrubby habitats, such as veery ( Catharus fuscescens), cedar waxwing ( Bombycilla cedrorum), chestnut-sided warbler ( Dendroica pensylvanica), magnolia warbler ( Dendroica magnolia), American redstart ( Setophaga ruticilla), mourning warbler ( Oporornis philadelphia) and white-throated sparrow ( Zonotrichia albicollis), benefited from selection cutting, with the timing of individual species’ responses related to changes in habitat structure and composition. Effects in one block were still evident 7 years after harvest. Guidelines that support a residual stocking target of 20 m 2/ha should promote the retention of mature forest bird communities, including ovenbird, while still providing habitat for early successional bird species.

AGE-RELATED TIMING AND PATTERNS OF PREBASIC BODY MOLT IN WOOD WARBLERS (PARULIDAE)

We compared timing and patterns of prebasic body molt between hatch-year (HY) and after-hatch-year (AHY) American Redstarts (Setophaga ruticilla) and Yellow Warblers (Dendroica petechia) in Ontario, Canada. In each body region of both species, there was no age-related difference in the proportion of individuals undergoing molt. Furthermore, there was no difference between HY and AHY American Redstarts in the overall timing of body molt; molt started in early July and lasted until early September. In contrast, HY Yellow Warblers started body molt in late June to early July, while adults began body molt in mid-July. Both American Redstarts and Yellow Warblers displayed age-class differences in the intensity and timing of molt among specific body regions. External factors (e.g., food availability and geographical distribution), and internal factors (e.g., physiological status) may contribute to variations in body molt timing observed in these two species.

Assessing Habitat Quality for a Migratory Songbird Wintering in Natural and Agricultural Habitats

As tropical forests are cleared, a greater proportion of migratory songbirds are forced to winter in agricultural and disturbed habitats, which, if poorer in quality than natural forests, could contribute to population declines. We compared demographic indicators of habitat quality for a focal species, the American Redstart (Setophaga ruticilla), wintering in Jamaican citrus orchards and shade coffee plantations with those in four natural habitats: mangrove, coastal scrub, coastal palm, and dry limestone forests. Demographic measures of habitat quality included density, age and sex ratio, apparent survival, and changes in body mass. Measures of habitat quality for redstarts in citrus and coffee habitats were generally intermediate between the highest (mangrove) and lowest (dry limestone) measurements from natural habitats. The decline in mean body mass over the winter period was a strong predictor of annual survival rate among habitats, and we suggest that measures of body condition coupled with survival data provide the best measures of habitat quality for nonbreeding songbirds. Density, which is far easier to estimate, was correlated with these more labor-intensive measures, particularly in the late winter when food is likely most limiting. Thus, local density may be useful as an approximation of habitat quality for wintering migrant warblers. Our findings bolster those of previous studies based on bird abundance that suggest arboreal agricultural habitats in the tropics can be useful for the conservation of generalist, insectivorous birds, including many migratory passerines such as redstarts.

Capital versus income breeding in a migratory passerine bird: evidence from stable-carbon isotopes

Birds meet the energetic demands of egg formation by using either endogenous reserves (capital breeding) or recently ingested nutrients (income breeding). Examining these strategies in migratory birds has been difficult because of the inability to assign the origin of egg nutrients. We used stable-carbon isotopes (δ13C values) to determine whether American Redstarts (Setophaga ruticilla (L., 1758)) form eggs using endogenous reserves acquired on tropical wintering areas or local dietary sources. Redstart diet tends to be enriched in 13C on tropical wintering areas; therefore, we predicted that if endogenous reserves are used to form eggs, then 13C would be enriched in first clutches relative to replacement clutches. We analyzed yolk (δ13CYK) samples from successive first, second, and third clutches and blood plasma (δ13CPL) sampled from females over the same time period. Values of δ13CYK in first-clutch and second-clutch eggs were significantly more positive than those in third-clutch eggs. Although the isotopic shift in yolk was in the direction predicted for a mixed capital–income strategy, δ13CPL, which represents the locally derived diet, varied seasonally in accordance with the shift in δ13CYK. Our findings indicate female Redstarts are primarily income breeders, forming eggs from an isotopically variable diet during the breeding season.

A Productivity Model for Parasitized, Multibrooded Songbirds

Abstract We present an enhancement of a simulation model to predict annual productivity for Wood Thrushes (Hylocichla mustelina) and American Redstarts (Setophaga ruticilla); the model includes effects of Brown-headed Cowbird (Molothrus ater) parasitism. We used species-specific data from the Driftless Area Ecoregion of Wisconsin, Minnesota, and Iowa to parameterize the model as a case study. The simulation model predicted annual productivity of 2.03 ± 1.60 SD for Wood Thrushes and 1.56 ± 1.31 SD for American Redstarts. Our sensitivity analysis showed that high parasitism lowered Wood Thrush annual productivity more than American Redstart productivity, even though parasitism affected individual nests of redstarts more severely. Annual productivity predictions are valuable for habitat managers, but productivity is not easily obtained from field studies. Our model provides a useful means of integrating complex life history parameters to predict productivity for songbirds that experience nest parasitism.

Social cues facilitate habitat selection: American redstarts establish breeding territories in response to song

For migratory songbirds nesting in northern temperate forests, a short breeding season demands that males rapidly establish territories. Because critical insect and vegetation resources are unavailable during spring arrival, we suggest that conspecifics serve as settlement cues for males new to a local population. To test conspecific attraction, we conducted playback experiments with American redstarts Setophaga ruticilla. Experimental results demonstrate that song playbacks strongly attract conspecifics, recruiting an average of 4.2 additional males per plot; adult males new to our sites increased, while yearling males failed to respond. Yearlings arrived 6 to 10 days later than adults, raising the possibility that yearlings responded to songs of early arriving adults rather than to playbacks. Our work indicates that conspecific attraction is an important mechanism for breeding habitat selection in an established population of a migratory forest songbird, but the effect is moderated by age, reproductive experience and arrival timing.

A PRODUCTIVITY MODEL FOR PARASITIZED, MULTIBROODED SONGBIRDS

Abstract We present an enhancement of a simulation model to predict annual productivity for Wood Thrushes (Hylocichla mustelina) and American Redstarts (Setophaga ruticilla); the model includes effects of Brown-headed Cowbird (Molothrus ater) parasitism. We used species-specific data from the Driftless Area Ecoregion of Wisconsin, Minnesota, and Iowa to parameterize the model as a case study. The simulation model predicted annual productivity of 2.03 ± 1.60 SD for Wood Thrushes and 1.56 ± 1.31 SD for American Redstarts. Our sensitivity analysis showed that high parasitism lowered Wood Thrush annual productivity more than American Redstart productivity, even though parasitism affected individual nests of redstarts more severely. Annual productivity predictions are valuable for habitat managers, but productivity is not easily obtained from field studies. Our model provides a useful means of integrating complex life history parameters to predict productivity for songbirds that experience nest parasitism.

SAMPLING VARIABILITY AND ESTIMATES OF DENSITY DEPENDENCE: A COMPOSITE-LIKELIHOOD APPROACH

It is well known that sampling variability, if not properly taken into account, affects various ecologically important analyses. Statistical inference for stochastic population dynamics models is difficult when, in addition to the process error, there is also sampling error. The standard maximum-likelihood approach suffers from large computational burden. In this paper, I discuss an application of the composite-likelihood method for estimation of the parameters of the Gompertz model in the presence of sampling variability. The main advantage of the method of composite likelihood is that it reduces the computational burden substantially with little loss of statistical efficiency. Missing observations are a common problem with many ecological time series. The method of composite likelihood can accommodate missing observations in a straightforward fashion. Environmental conditions also affect the parameters of stochastic population dynamics models. This method is shown to handle such nonstationary population dynamics processes as well. Many ecological time series are short, and statistical inferences based on such short time series tend to be less precise. However, spatial replications of short time series provide an opportunity to increase the effective sample size. Application of likelihood-based methods for spatial time-series data for population dynamics models is computationally prohibitive. The method of composite likelihood is shown to have significantly less computational burden, making it possible to analyze large spatial time-series data. After discussing the methodology in general terms, I illustrate its use by analyzing a time series of counts of American Redstart (Setophaga ruticilla) from the Breeding Bird Survey data, San Joaquin kit fox (Vulpes macrotis mutica) population abundance data, and spatial time series of Bull trout (Salvelinus confluentus) redds count data.

Predicting the consequences of carry-over effects for migratory populations.

Migratory animals present a unique challenge for predicting population size because they are influenced by events in multiple stages of the annual cycle that are separated by large geographic distances. Here, we develop a model that incorporates non-fatal carry-over effects to predict changes in population size and show how this can be integrated with predictive models of habitat loss and deterioration. Examples from Barn swallows, Greater snow geese and American redstarts show how carry-over effects can be estimated and integrated into the model. Incorporation of carry-over effects should increase the predictive power of models. However, the challenge for developing accurate predictions rests both on the ability to estimate parameters from multiple stages of the annual cycle and to understand how events between these periods interact to influence individual success.

NONBREEDING HABITAT OCCUPANCY AND POPULATION PROCESSES: AN UPGRADE EXPERIMENT WITH A MIGRATORY BIRD

Evidence is accumulating that winter habitats occupied by migratory birds produce differences in individual condition that can carry over into subsequent stages of the annual cycle. Despite strong observational evidence, experimental work is needed to strengthen support for this hypothesis. We experimentally upgraded individual American Redstarts (Setophaga ruticilla) from low-quality second-growth scrub habitat to high-quality mangrove forest habitat by permanently removing behaviorally dominant, primarily adult males from mangrove, allowing females and immature males from scrub to colonize vacated territories. Prior to the manipulation, upgraded and control redstarts had stable-carbon isotope values in their blood indicative of scrub habitat occupancy and were comparable in body mass. Relative to control birds that overwintered exclusively in scrub, upgraded redstarts incorporated mangrove isotopic signatures, maintained body mass from winter to spring, departed earlier on spring migration, and returned at a higher rate in the following winter. Furthermore, insect biomass on upgrade territories was significantly greater than on control territories, suggesting food availability as a proximate mechanism underlying gradients of nonbreeding habitat suitability. Findings here demonstrate that winter habitat occupancy can be an important determinant of individual performance in migratory birds. Restricted access to food-rich winter habitats may limit survival of females and immature males, an outcome that could be an important driver of population structure and dynamics.

Passerine migrants respond to variation in predation risk during stopover

During travel, migrants may encounter unfamiliar habitats and predators and visit sites for which they lack information on predation risk. Temporary stops during migration permit only limited opportunities to gather information about risk, and other priorities, such as the need to forage, may restrict these opportunities. Under these conditions, the extent to which migrants respond to variations in predation risk is unclear. We studied small passerine birds during migratory stopover to determine whether their behaviour was related to variation in risk of capture by migrating birds of prey. We used two approaches, observational and experimental. Observations revealed that blue-grey gnatcatchers, Polioptila caerulea, and American redstarts, Setophaga ruticilla, moved deeper into oak shrubs as the number of sharp-shinned hawks, Accipiter striatus, at the site increased. Furthermore, blue-grey gnatcatchers moved at slower rates as counts of hawks increased. The experiment revealed that blue-grey gnatcatchers had lower rates of both movement and foraging after exposure to a gliding model hawk. These results provide evidence that predator avoidance remains a priority during migration and that migrants are able to assess risk to some extent during temporary stopover. In addition, the results suggest that predator avoidance behaviour may limit foraging opportunities during stopover by restricting habitat use.

Brooding Behavior in an Adult Male American Redstart

Abstract We describe the first observation of a male American Redstart (Setophaga ruticilla L.) brooding nestlings. Although this behavior has been documented in other North American members of the Family Parulidae, this is the first case in American Redstarts.

Tracking habitat use of a long‐distance migratory bird, the American redstart Setophaga ruticilla, using stable‐carbon isotopes in cellular blood

The successful use of stable isotopes to track migratory animals between different seasons of the annual cycle depends, in part, on the turnover rate of isotopes in sample tissue. We examined whether stable‐carbon isotopes in the blood of a long‐distance migratory bird, the American redstart Setophaga ruticilla, sampled upon arrival to the temperate breeding grounds could be used to track the quality of habitat used the previous season on the tropical wintering grounds. Stable‐carbon isotopes in red‐blood cells sampled upon arrival (δ13CRBC) were significantly less negative relative to: 1) plasma sampled upon arrival from the same individuals, 2) red‐blood cells of redstarts recaptured more than a month later on the breeding grounds, and 3) nestling feathers grown at the same breeding location. δ13CRBC was also significantly different between sexes, consistent with findings from the wintering grounds where sex‐biased habitat use is known to occur. Although individuals likely integrate some isotopic signatures during migration, we provide evidence that cellular blood can be used to track the relative habitat use of migratory birds during the wintering period. Non‐destructive methods of sampling stable‐isotopes, such as this, are particularly useful because it provides a technique for tracking the patterns of habitat use and/or geographic location of migratory animals. Such approaches allow researchers to understand how events throughout the annual cycle interact to influence population dynamics.

Reproductive Effort, Molting Latitude, and Feather Color in a Migratory Songbird

Toward the end of the breeding season, migratory songbirds face crucial tradeoffs between the timing of reproduction, molt, and migration. Using stable hydrogen isotopes, we show that male American redstarts investing in high levels of reproduction late in the season adopt a unique strategy of combining molt and migration. Tail feathers molted during migration also reflect less orange-red light, indicating reduced carotenoid concentration. Thus, we show how reproduction in a migratory animal can influence both life history strategies (location of molt) and social signals (feather color) during subsequent periods of the annual cycle.

Partial cutting of woodlots in an agriculture-dominated landscape: effects on forest bird communities

We studied the short-term effects of partial cutting on the forest bird communities of mixed maple forests in an agriculture-dominated landscape in southwestern Ontario. Blocks that had been recently harvested were grouped according to provincial silvicultural guidelines (standard and heavy cuts) and compared with blocks that had been uncut for at least 24 years (old cuts). We found significant differences in forest bird community structure between standard and heavy cuts and between heavy and old cuts, but not between standard and old cuts. Heavy cuts had more species and more individuals than old cuts, the result primarily of greater numbers of early-successional species. Brown creeper (Certhia americana Bonap.) was the only species to show a significant negative response to harvesting and was the best indicator of old cuts, while indigo bunting (Passerina cyanea L.), brown-headed cowbird (Molothrus ater Bodd.), chestnut-sided warbler (Dendroica pensylvanica L.), American redstart (Setophaga ruticilla L.), and great crested flycatcher (Myiarchus crinitus L.) were all significant indicators of heavy cuts. Our research suggests that it is possible to protect native bird communities in southwestern Ontario by using the single-tree selection system to meet the minimum basal area targets and harvest intensities recommended in provincial silvicultural guidelines.

Using Isotopic Variance to Detect Long-Distance Dispersal and Philopatry in Birds: An Example with Ovenbirds and American Redstarts

AbstractUnderstanding movements of individual birds between breeding sites (breeding dispersal) or between natal sites and the site of first breeding (natal dispersal) is crucial to the modeling of population dynamics. Unfortunately, these aspects of demography are poorly understood for avian species in general, and for migratory songbirds in particular. This is because it is often impossible to sample broadly enough to relocate marked birds that have moved. We used stable-hydrogen (δD) and carbon (δ13C) isotope analyses of the feathers of 139 American Redstarts (Setophaga ruticilla) and 193 Ovenbirds (Seiurus aurocapillus) to evaluate evidence for individuals molting feathers at locations other than their breeding sites from the previous year. We sampled outer rectrices from breeding populations at three extensive boreal forest sites (Prince Albert National Park and Duck Mountain, Saskatchewan, and Lac La Biche, Alberta) and at three isolated forest tracts (Cypress Hills, and Moose Mountain, Saskatchewan, and Turtle Mountain, Manitoba) in western Canada. Based on outlier analysis of δD measurements, we found evidence for long-distance dispersal ranging from 0–29% of individuals. For both species, second-year birds had higher variance in δD values suggesting they had a higher probability of originating from elsewhere compared to after-second-year birds.Utilización de la Variación Isotópica para Detectar Dispersión de Larga Distancia y Filopatría en las Aves: Un ejemplo con Seiurus aurocapillus y Setophaga ruticillaResumen. Entender los movimientos de aves individuales entre sitios de cría (dispersión reproductiva) o entre el sitio de nacimiento y el sitio del primer evento reproductivo (dispersión natal) es crucial para modelar la dinámica de poblaciones. Desafortunadamente, estos aspectos demográficos están poco entendidos para las especies de aves en general y para las aves canoras migratorias en particular. Esto se debe a que es usualmente imposible realizar muestreos lo suficientemente amplios como para relocalizar a las aves marcadas que se desplazaron. Usamos análisis de isótopos estables de hidrógeno (δD) y carbono (δ13C) de las plumas de 139 individuos de Setophaga ruticilla y de 193 individuos de Seiurus aurocapillus para evaluar la presencia de individuos que han mudado sus plumas en localidades distintas a las de sus sitios reproductivos del año anterior. Muestreamos las rectrices externas en poblaciones reproductivas de tres sitios extensos de bosque boreal (Parque Nacional Prince Albert y Duck Mountain, Saskatchewan, y Lago La Biche, Alberta) y de tres parches de bosque aislados (Cypress Hills y Moose Mountain, Saskatchewan, y Turtle Mountain, Manitoba) en el oeste de Canadá. Basados en análisis de datos extremos (outliers) de medidas de δD, encontramos evidencia de dispersión de larga distancia que comprendió entre el 0–29% de los individuos. Para ambas especies, las aves del segundo año de vida presentaron mayor varianza en los valores de δD, sugiriendo que poseen una mayor probabilidad de haberse originado en algún otro lugar comparado con aves de más de dos años de vida.

Arrival timing and seasonal reproductive performance in a long-distance migratory landbird

The date when a landbird migrant arrives on its breeding grounds may have reproductive consequences. Generally, early arriving individuals begin breeding earlier and consequently experience greater seasonal reproductive performance. Here, we describe relationships between arrival timing and seasonal reproductive performance in the American redstart (Setophaga ruticilla), a long-distance passerine migrant, arriving at northerly breeding grounds in Michigan’s eastern Upper Peninsula. Evidence suggests that both males and females benefited from early arrival at the breeding grounds. Early males appeared to settle on higher quality territories and hatched nestlings sooner than later arrivals. Early females began their clutches early, produced heavier nestlings and possibly laid more eggs than later arrivals. Larger clutches and heavier offspring increase the likelihood of offspring recruiting into the breeding population. The findings of this study point to fitness consequences arising from when a bird arrives at its breeding grounds. These results also have implications for understanding how events occurring during spring migration influence reproductive performance as migratory delays likely influence arrival timing.

SPATIAL FORAGING DIFFERENCES IN AMERICAN REDSTARTS ALONG THE SHORELINE OF NORTHERN LAKE HURON DURING SPRING MIGRATION

Lowland coniferous forests adjacent to northern Lake Huron provide important stopover habitat for landbirds during spring migration. Large numbers of aquatic insects emerging from nearshore waters of northern Lake Huron appear to be an important food source. In this study we compared the foraging behavior of a long-distance landbird migrant, the American Redstart (Setophaga ruticilla), in areas with high densities of emergent aquatic insects to areas with few or no emergent aquatic insects to assess the significance of these arthropods as an early spring food source. Redstarts foraged differently in shoreline habitats relative to inland habitats of similar vegetation composition. Both males and females gleaned significantly more in shoreline habitats as compared to inland areas of similar vegetation composition, and inland birds performed more sally strikes than birds at the shoreline. Both sexes also varied the use of tree species in which they foraged. Redstarts used northern white cedar (Thuja occidentalis) more at shoreline than inland, while inland redstarts foraged in deciduous trees more than at the shoreline. We suggest that differences in foraging between shoreline and inland locations were responses to differences in prey types and abundance, most notably the presence of emergent aquatic insects (Diptera: Chironomidae) in shoreline habitat. Our results complement those of previous work, suggesting that midges provide a critical early season resource for landbirds migrating through Michigan's eastern Upper Peninsula during spring. Received 30 September 2003, accepted 26 March 2004. During spring and early summer in temper- ate North America, large numbers of aquatic insects that have metamorphosed into sexually mature adults often amass in terrestrial habi- tats adjacent to riparian and lacustrine systems (Armitage 1995, McCafferty 1998). These in- vertebrates are relatively weak fliers (e.g., Ko- vats et al. 1996) and tend to be restricted to nearshore terrestrial habitats. In Michigan's eastern Upper Peninsula, midges (Diptera: Chironomidae) are the predominant aquatic arthropods when migratory landbirds stop during spring migration. These invertebrates swarm profusely in shoreline areas while be- ing virtually nonexistent inland (DNE unpubl. data). Recent evidence suggests that lowland co- niferous forests adjacent to northern Lake Hu- ron provide important stopover habitat for spring migrants. More landbirds are found in 1

UNDERSTANDING SURVIVAL AND ABUNDANCE OF OVERWINTERING WARBLERS: DOES RAINFALL MATTER?

We investigated relationships between warbler abundance and survival rates measured on a Puerto Rican wintering site and rainfall patterns measured on the wintering site and in regions where these warblers breed, as estimated using stable-isotope analysis (δD) of feathers collected from wintering birds. We banded birds using constant-effort mist netting from January 1989–2003 in the Gu´nica Forest of southwestern Puerto Rico. Black-and-white Warblers (Mniotilta varia), American Redstarts (Setophaga ruticilla), and Ovenbirds (Seiurus aurocapilla) dominated the Neotropical migrant capture totals each winter, with resulting sample sizes large enough to estimate survival rates. Estimates of capture probability from survival modeling allowed us to estimate abundance from mist-netting capture totals for Black-and-white Warblers and Ovenbirds. Stable-hydrogen isotopes showed that the three focal species came mostly from the eastern United States. Black-and-white Warbler abundance was related to rainfall total deviations from normal in Guánica Forest, and Ovenbird abundance was related to total annual rainfall in the United States. Survival models with rainfall covariates were weakly supported overall, but apparent survival of Black-and-white Warblers and American Redstarts was negatively related to rain during the first 6 months of the year at Guánica, and Ovenbird survival was related to rainfall during the spring in the southeastern U.S. Abundance and apparent survival exhibited similar, species-specific patterns of association with rainfall for Black-and-white Warblers and Ovenbirds. Winter rainfall was important to demographic parameters of Black-and-white Warblers, and breeding-season rain was important to Ovenbirds. Entendiendo los Patrones de Supervivencia y Abundancia de Parúlidos Residentes de Invierno: ¿Es Importante la Precipitación? Resumen. Investigamos las relaciones entre la abundancia y las tasas de supervivencia de parúlidos residentes de invierno en Puerto Rico y los patrones de precipitación de los sitios invernales y de las áreas de anidación, éstas últimas deducidas a partir del análisis de isótopos estables (δD) en plumas colectadas de las aves migratorias. Las aves fueron capturadas y anilladas utilizando redes de niebla en el Bosque de Guánica en el suroeste de Puerto Rico durante el mes de enero, desde 1989 hasta el 2003. Las especies de aves neotropicales con mayor número de capturas totales durante cada invierno fueron Mniotilta varia, Setophaga ruticilla y Seiurus aurocapilla, con un tamaño de muestra lo suficientemente grande como para estimar sus tasas de supervivencia. La estimación de las probabilidades de captura a partir de los modelos de supervivencia nos permitieron evaluar la abundancia utilizando datos de capturas totales para Mniotilta varia y Seiurus aurocapilla. Los isótopos de hidrógeno estable mostraron que las tres especies de aves focales provinieron principalmente de la región Este de Estados Unidos. La abundancia de Mniotilta varia estuvo relacionada a las variaciones totales de precipitación en el Bosque de Guánica y la abundancia de Seiurus aurocapilla estuvo relacionada a la precipitación anual total en los Estados Unidos. Los modelos de supervivencia con covariables de precipitación tuvieron muy poco respaldo. Sin embargo, la supervivencia aparente de Mniotilta varia y Setophaga ruticilla estuvo relacionada negativamente a la precipitación durante los primeros seis meses del año en Guánica y la supervivencia de Seiurus aurocapilla estuvo relacionada a la precipitación durante la estación de primavera en el sureste de Estados Unidos. La abundancia y la supervivencia aparente mostraron patrones de asociación similares y específicos para cada especie con la precipitación para Mniotilta varia y Seiurus aurocapilla. La precipitación de invierno fue un factor importante para determinar los patrones demográficos de Mniotilta varia y la precipitación durante la temporada de anidación también fue un factor significativo para Seiurus aurocapilla.