Survival and Movements of Fledgling Western Bluebirds

Wightman, Catherine S.

doi:10.1894/mh-33.1

Cited by 16 publications

(10 citation statements)

References 17 publications

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“…2). Similar results have been found for other altricial birds that were also investigated using radio telemetry, which leaves little doubt about the accuracy of the pattern (e.g., Adams et al 2006;King et al 2006;Berkeley et al 2007;Rush and Stutchbury 2008;Wightman 2009;Grüebler and Naef-Daenzer 2010).…”

Section: Discussionsupporting

confidence: 73%

Survival and development of predator avoidance in the post-fledging period of the Whinchat (Saxicola rubetra): consequences for conservation measures

Tome

Denac

2011

J Ornithol

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Farmland bird populations in Europe are shrinking, largely due to modern agriculture practices. In grasslands, the shift to early mowing is believed to be particularly responsible for this decline because it is interwoven with breeding time-a change that birds in general have not adapted to. We studied the post-fledging survival of the Whinchat, an altricial grassland passerine. Based on a sample of 74 radiotagged young Whinchats, we confirmed that they fledge at 13-15 days. Twenty-four fledged birds died, while 18 of them were depredated. The survival probability of young Whinchats, calculated using Kaplan-Meier estimates, was lowest during the first day after fledging, and slowly leveled off later. In total, the probability that a juvenile survived the first month after fledging was 0.52. During the first days after fledging, all chicks were found hiding on the ground among the grass stubble. The generalized linear mixed model predicts that half of the fledglings at 20 days old and 20% at 22 days old (8-10 days after fledging) will not escape but will instead remain still when approached by a threat. Sixteen depredations occurred during this period, all by mammal predators. Afterwards, the fledglings changed their strategy, escaping through flight. After 12 days, more and more of the chicks were found exposed on top of the grass or on the bush instead of hiding on the ground. The transition from sit and hide to escape behavior reduced the predation rate considerably. Only two chicks were depredated later, both by an avian predator. Due to the initial predator avoidance strategy, the current conservation measure (to postpone mowing until the chicks in 80% of all nests have fledged) is not sufficient to halt population decline on improved meadows. We suggest that at least 10 days more, and possibly even 14 days more, are necessary to maintain viable Whinchat populations.Zusammenfassung Die Praktiken in der modernen Landwirtschaft führen in Europa zu einer Abnahme der Vogelpopulationen auf Ackerland. Vor allem der Wechsel hin zu früher Gras-Mahd wird dafür verantwortlich gemacht, weil diese immer häufiger in die Brutzeit fällt-eine Veränderung, an die sich die Vögel nicht anpassen konnten. Wir untersuchten das Ü berleben in der Zeit direkt nach dem Flüggewerden bei Braunkehlchen, einem Nesthocker unter den auf Wiesen lebenden Singvögeln. Anhand von 74 mit Sendern versehenen, jungen Braunkehlchen konnten wir bestätigen, dass sie im Alter von 13 bis 15 Tagen flügge werden. 24 der markierten Vögel fielen aus, weil sie starben; 18 von ihnen wurden erbeutet. Die Ü berlebenswahrscheinlichkeit der jungen Braunkehlchen wurde mit der Kaplan-Meier-Methode eingeschätzt; sie war in den ersten fünf Tagen nach dem Flüggewerden am niedrigsten und pendelte sich danach langsam ein. Insgesamt lag die Ü berlebenswahrscheinlichkeit für den ersten Monat nach Flüggewerden bei 0,52. In den ersten Tagen versteckten sich alle Küken zwischen den Grasstoppeln am Boden. Das generalisierte lineare gemischte Modell (GLMM) sagt voraus, dass 50%...

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Section: Discussionsupporting

confidence: 73%

Survival and development of predator avoidance in the post-fledging period of the Whinchat (Saxicola rubetra): consequences for conservation measures

Tome

Denac

2011

J Ornithol

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“…As expected, distance moved from the nest increased with age as young become more mobile and began feeding themselves, but movements back to the nest site were also observed. Increasing distance from the nest is well documented in studies of the Eastern Meadowlark (Kershner et al 2004), Western Bluebird (Wightman 2009), Dickcissel (Berkeley et al 2007), Hooded Warbler (Rush and Stutchbury 2008), and Ovenbirds and Worm-eating Warbler (Vitz and Rodewald 2010).…”

Section: Discussionmentioning

confidence: 81%

Survival and Movements of Fledgling Willow and Dusky Flycatchers

Vormwald¹,

Morrison²,

Mathewson³

et al. 2011

The Condor

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Estimates of productivity usually ignore survival during the postfledging period, the time between a bird's leaving its nest and departure for migration or movement to an area for wintering. During the first 1-3 weeks after fledging, young birds are limited in mobility, making them vulnerable to fatality, especially from prédation. To help fill this information gap, we examined the period of postñedging dependence of the Willow {Em-pidonax trailla) and Dusky {E. oberholseri) Flycatchers in the central Sierra Nevada, California. For fledglings we examined faetors that influenced survival, movements, and habitat use and home-range size. We observed family groups daily during the postfledging dependence period and resighted individual band combinations. Fledglings' survival ranged from 46% to 76% and varied by year and species. Fledglings moved on average 45 m from the nest per day during the dependence period. We detected family groups in their natal meadows from 13 to 33 days. We detected Willow Flycatchers in riparian shrubs 94% of the time, along the upland forest edge for the remaining 6%. We detected Dusky Flycatchers in riparian shrubs 70% of the time, in upland forest for the remaining 30%. For both years of our study combined, mean 95% home-range sizes were 1.80 ± 1.44 (SD) ha for the Willow Flycatcher and 1.82 ± 1.70 ha for the Dusky Flycatcher. Mean 50% core areas were 0.33 ± 0.27 ha for the Willow Flycatcher and 0.38 ± 0.44 ha for the Dusky Flycatcher. Supervivencia y Movimientos de Volantones de Empidonax trailla y E. oberholseriResumen. Los estimados de productividad usualmente ignoran la supervivencia durante el periodo posterior al emplumamiento, el tiempo entre que un ave deja el nido y que parte en migración o se mueve a un área para invernar. Durante las primeras 1-3 semanas luego de emplumar, las aves jóvenes tienen una movilidad limitada, haeiendo que sean vulnerables a una fatalidad, especialmente por depredación. Para ayudar a llenar este vacio de información, examinamos el periodo de dependencia posterior al emplumamiento en Empidonax trailla y E. oberholseri en la Sierra Nevada central. California. Para los volantones, examinamos los factores que influeneiaron la supervivencia, los movimientos, el uso de habitat y el tamaño del ámbito hogareño. Observamos diariamente grupos familiares durante el periodo de dependencia posterior al emplumamiento y realizamos observaciones repetidas de combinaciones individuales de anillos. La supervivencia de los volantones fluctuó entre 46% y 76% y varió por año y especie. Los volantones se movieron en promedio 45 m desde el nido por dia durante el periodo de dependencia. Detectamos grupos familiares en sus prados natales desde 13 a 33 dias. Detectamos la presencia de E. trailla en arbustos ribereños el 94% de las veces y a lo largo del borde del bosque en la zona alta no inundable el 6% restante. Detectamos a E. oberholseri en los arbustos ribereños el 70% de las veces y en las tierras altas no inundables el 30% restante. Combinando los dos años de nuestro ...

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“…Black‐capped vireo fledgling survival estimates in Kerr County are similar to other songbirds (e.g., western bluebirds [ Sialia mexicana ; Wightman ], dickcissels [ Spiza americana ; Suedkamp Wells et al ], and eastern meadowlarks [ Sturnella magna ; Kershner et al ]), though we think our estimates for vireo fledgling survival are conservative. Unlike other songbirds, such as willow flycatchers ( Empidonax trailii ) and western bluebirds that remain in family groups after fledging (Wightman , Vormwald et al ), black‐capped vireos may split broods between the adults (T. L. Pope, personal observation; Grzybowski ). Fledglings of species that remain in family groups are easier to relocate by finding the adults.…”

Section: Discussionmentioning

confidence: 52%

Woodlands as quality breeding habitat for black-capped vireos

2013

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Identifying vegetation types that result in the highest quality habitat will help direct management and conservation activities designed to recover endangered species. Shrubland is considered to result in high quality habitat for black-capped vireos (Vireo atricapilla), whereas deciduous and oak-juniper woodlands are considered to result in marginal habitat (i.e., lower quality). We investigated differences in nest and fledgling survival among shrubland and woodland vegetation types. We monitored 302 black-capped vireo nests in 259 territories from 2008 to 2010 in Kerr County, Texas and collected vegetation data at each nest. We also resighted 350 fledglings to estimate individual survival. Nest survival and fecundity did not differ statistically among vegetation types. Although nest-site characteristics differed among vegetation types, none affected nest survival. Nests that were parasitized were less likely to survive and parasitism was the only variable to affect survival of those measured. Parasitism frequency was nearly twice as great in shrubland (22%) than in either woodland type (12% in each) and varied by year (31% in 2008 to 0% in 2010). Vegetation type and proximity of the nest to oak-juniper woodland did not affect fledgling survival. Our results suggest woodlands may result in good quality habitat in areas with large populations of black-capped vireos. Recognizing woodlands as non-typical, yet good quality, habitat will allow managers to incorporate these vegetation types into management plans and make recommendations for conservation incentive programs directed at private landowners. ß 2013 The Wildlife Society.

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Survival and Movements of Fledgling Western Bluebirds

Cited by 16 publications

References 17 publications

Survival and development of predator avoidance in the post-fledging period of the Whinchat (Saxicola rubetra): consequences for conservation measures

Survival and development of predator avoidance in the post-fledging period of the Whinchat (Saxicola rubetra): consequences for conservation measures

Survival and Movements of Fledgling Willow and Dusky Flycatchers

Woodlands as quality breeding habitat for black-capped vireos

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