Background:Accurate nestling age is valuable for studies on nesting strategies,productivity,and impacts on repro-ductive success.Most aging guides consist of descriptions and photographs that are time consuming to rea...Background:Accurate nestling age is valuable for studies on nesting strategies,productivity,and impacts on repro-ductive success.Most aging guides consist of descriptions and photographs that are time consuming to read and subjective to interpret.The Western Bluebird(Sialia mexicana)is a secondary cavity-nesting passerine that nests in coniferous and open deciduous forests.Nest box programs for cavity-nesting species have provided suitable nesting locations and opportunities for data collection on nestling growth and development.Methods:We developed models for predicting the age of Western Bluebird nestlings from morphometric meas-urements using model training and validation.These were developed for mass,tarsus,and two different culmen measurements.Results:Our models were accurate to within less than a day,and each model worked best for a specific age range.The mass and tarsus models can be used to estimate the ages of Western Bluebird nestlings 0-10 days old and were accurate to within 0.5 days for mass and 0.7 days for tarsus.The culmen models can be used to estimate ages of nest-lings 0-15 days old and were also accurate to within less than a day.The daily mean,minimum,and maximum values of each morphometric measurement are provided and can be used in the field for accurate nestling age estimations in real time.Conclusions:The model training and validation procedures used here demonstrate that this method can create aging models that are highly accurate.The methods can be applied to any passerine species provided sufficient nest-ling morphometric data are available.展开更多
Los Alamos National Laboratory (LANL) was established in 1943 as part of the Manhattan Project to build nuclear weapons, and currently operates as a national research laboratory. As part of an ongoing assessment of si...Los Alamos National Laboratory (LANL) was established in 1943 as part of the Manhattan Project to build nuclear weapons, and currently operates as a national research laboratory. As part of an ongoing assessment of site-related ecological risk at LANL, western bluebird (Sialia mexicana) and ash-throated flycatcher (Myiarchus cinerascens) eggs were collected from 1997 to 2012 and analyzed for 18 inorganic elements. Concentrations of many inorganic elements in eggs were below reporting limits. Between species comparisons revealed that western bluebird eggs had higher levels of barium while ash-throated flycatcher eggs had higher levels of mercury. No statistically significant differences were observed in concentrations of inorganic elements in western bluebird eggs collected from the study area (which consists of areas within the current and historic LANL boundary) and from a non-industrial reference site;nor were any statistically significant differences observed between two canyons of interest, known to have received effluents and storm water runoff from LANL facilities, and the non-industrial reference site. Inorganic element levels detected in western bluebirds were typically within the range measured in eggs of other passerine in the published literature. These data suggest that concentrations of inorganic elements in passerine eggs collected from the study area appear to be at levels causing negligible risks to local bird populations.展开更多
文摘Background:Accurate nestling age is valuable for studies on nesting strategies,productivity,and impacts on repro-ductive success.Most aging guides consist of descriptions and photographs that are time consuming to read and subjective to interpret.The Western Bluebird(Sialia mexicana)is a secondary cavity-nesting passerine that nests in coniferous and open deciduous forests.Nest box programs for cavity-nesting species have provided suitable nesting locations and opportunities for data collection on nestling growth and development.Methods:We developed models for predicting the age of Western Bluebird nestlings from morphometric meas-urements using model training and validation.These were developed for mass,tarsus,and two different culmen measurements.Results:Our models were accurate to within less than a day,and each model worked best for a specific age range.The mass and tarsus models can be used to estimate the ages of Western Bluebird nestlings 0-10 days old and were accurate to within 0.5 days for mass and 0.7 days for tarsus.The culmen models can be used to estimate ages of nest-lings 0-15 days old and were also accurate to within less than a day.The daily mean,minimum,and maximum values of each morphometric measurement are provided and can be used in the field for accurate nestling age estimations in real time.Conclusions:The model training and validation procedures used here demonstrate that this method can create aging models that are highly accurate.The methods can be applied to any passerine species provided sufficient nest-ling morphometric data are available.
文摘Los Alamos National Laboratory (LANL) was established in 1943 as part of the Manhattan Project to build nuclear weapons, and currently operates as a national research laboratory. As part of an ongoing assessment of site-related ecological risk at LANL, western bluebird (Sialia mexicana) and ash-throated flycatcher (Myiarchus cinerascens) eggs were collected from 1997 to 2012 and analyzed for 18 inorganic elements. Concentrations of many inorganic elements in eggs were below reporting limits. Between species comparisons revealed that western bluebird eggs had higher levels of barium while ash-throated flycatcher eggs had higher levels of mercury. No statistically significant differences were observed in concentrations of inorganic elements in western bluebird eggs collected from the study area (which consists of areas within the current and historic LANL boundary) and from a non-industrial reference site;nor were any statistically significant differences observed between two canyons of interest, known to have received effluents and storm water runoff from LANL facilities, and the non-industrial reference site. Inorganic element levels detected in western bluebirds were typically within the range measured in eggs of other passerine in the published literature. These data suggest that concentrations of inorganic elements in passerine eggs collected from the study area appear to be at levels causing negligible risks to local bird populations.
