Adult and Juvenile Survival of Black-Capped Vireos Within a Large Breeding Population in Texas

Abstract

We used mark-recapture and information-theoretic model selection methodologies to estimate survival and recapture probabilities for the federally endangered Black-capped Vireo (Vireo atricapilla) at Fort Hood Military Reservation, Texas, during 1997. Adult survival was time-dependent and ranged from 0.36 to 0.60. Although we found no support for sex-specific differences in adult survival, recapture probability was greater for males (0.83) than females (0.58). Adult survival differed among three study areas, which could be indicative of site-specific differences in habitat quality. Survival of juveniles from their hatching year to the following spring was dependent on age at banding. Survival of juveniles banded as nestlings or soon after fledging was low (0.10). The survival estimate for juveniles banded after postfledging independence was substantially higher (0.42). Because juvenile survival is difficult to estimate for passerines, it is often set at an arbitrary value such as one third or half of adult survival. Our survival estimate for juveniles banded after postfledging independence was higher than suggested by either of these commonly used guidelines. We acknowledge that our survival estimates are probably biased low because we could not differentiate between dispersal and mortality. Adoption of a study design that includes core areas where vireos are marked and resighted in subsequent years as well as surrounding resight-only areas would presumably improve survival estimates for both adults and juveniles. More robust estimates of survival could greatly improve population viability analyses for this endangered species. Supervivencia de Adultos y Juveniles de Vireo atricapilla en una Gran Población Reproductiva en TexasResumen. Utilizamos los métodos de marcado y recaptura y de selección de modelos con base en la teoría de la información para estimar las probabilidades de supervivencia y recaptura para una especie en peligro a nivel federal, Vireo atricapilla, en la Reserva Militar Fort Hood, Texas, entre 1997 y 2006. La supervivencia de los adultos fue dependiente del tiempo y varió entre 0.36 a 0.60. Aunque no encontramos evidencia de diferencias especí-ficas para cada sexo en la supervivencia de adultos, la probabilidad de recaptura fue mayor para los machos (0.83) que para las hembras (0.58). La supervivencia de los adultos difirió entre las tres áreas de estudio, lo que podría indicar diferencias en la calidad del hábitat específicas para cada sitio. La supervivencia de los juveniles desde su año de eclosión hasta la primavera siguiente dependió de la edad al momento de ser anillados. La supervivencia de los juveniles que fueron anillados cuando se encontraban en el nido o luego después de que lo abandonaran fue baja (0.10). Los estimados de supervivencia para los juveniles anillados durante el periodo de independencia posterior al abandono del nido fueron substancialmente mayores (0.42). Debido a que la supervivencia de los juveniles es difícil de estimar para las aves paseriformes, generalmente se es...

How far is too close? restricted, sex‐biased dispersal in black‐capped vireos

“…Under this scenario, it is more likely that gene flow into distant populations would occur gradually and via intermediary connecting populations. Although there is anecdotal evidence of long‐distance (two birds dispersing approximately 70 km) dispersal by black‐capped vireos (Kostecke & Cimprich 2008), spatial autocorrelation suggests that short‐distance movement may be the norm for males. A stepping stone model is also supported by the finding of a significant isolation‐by‐distance among vireo populations, with only spatially proximate populations exhibiting no genetic differentiation (Barr et al.…”

“…Black-capped vireos are considered socially monogamous (Graber 1961), while it is unclear if this corresponds with genetic monogamy. Little is known about long-distance natal dispersal in this species-the longest recorded dispersal was about 78 km (Kostecke & Cimprich 2008) based on band-recapture data. We reported in earlier studies that, despite the high vagility of this migratory bird, the 12 remnant populations are undergoing substantial differentiation , and over the past 100 years, this species has suffered declines in genetic diversity, along with significantly increased degree of genetic differentiation (Athrey et al 2012).…”

Demography and dispersal of juvenile and adult Brown-headed Cowbirds (Molothrus ater) in the eastern Sierra Nevada, California, estimated using multistate models

“…However, many of these focus solely on adults. Much of our knowledge of juvenile survival and dispersal has been in species that exhibit high return rates of all ages, such as colonial nesting seabirds (Weimerskirch et al 1997, Oro et al 2004, cooperative breeders Fitzpatrick 1996, Fox et al 2006), and isolated or endangered populations (Altwegg et al 2000, Keyser et al 2004, Kostecke and Cimprich 2008, Low and Pärt 2009. In many other bird species, including most passerines, juveniles exhibit high rates of dispersal and, thus, are difficult to sample with the efficiency required of mark-recapture analyses.…”

“…Most reliable estimates of juvenile survivorship in passerines, using either mark-recapture analyses or return rates, are from somewhat isolated or endangered populations (e.g., Woolfenden and Fitzpatrick 1996, Ringsby et al 1999, Altwegg et al 2000, Keyser et al 2004, Kostecke and Cimprich 2008, although estimates for more "typical" populations are starting to emerge (e.g., Gardali et al 2003, Githiru and Lens 2007, Lehnen and Rodewald 2009. In most cases where statistical modeling of mark-recapture data is used (including our study and others listed above), juvenile annual apparent survivorship is estimated to be quite high, sometimes even >40%.…”

Dependence of the Endangered Black‐Capped Vireo on Sustained Cowbird Management

“…We based our estimates of vireo vital rates on a 9‐year mark‐recapture study (Kostecke & Cimprich ) and 8 years of intensive nest monitoring (Cimprich & Heimbuch ) conduced on Fort Hood (Supporting Information). The population growth rate for a 2‐stage vireo population projection matrix (i.e., Leslie matrix) parameterized with empirical estimates of fecundity and juvenile and adult survival from these studies (Table ) is declining (λ = 0.92) even in the absence of cowbird parasitism.…”