Variation in offspring development is driven more by weather and maternal condition than predation risk
Abstract Variation in offspring development is expected to be driven by constraints on resource allocation between growth and maintenance (e.g. thermoregulation). Rapid post‐natal development decreases predation risk to offspring, while inclement weather likely prolongs development. For taxa with pa...
Published in: | Functional Ecology |
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Main Authors: | , , , |
Other Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Wiley
2019
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Subjects: | |
Online Access: | http://dx.doi.org/10.1111/1365-2435.13273 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2F1365-2435.13273 https://onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.13273 https://onlinelibrary.wiley.com/doi/full-xml/10.1111/1365-2435.13273 https://besjournals.onlinelibrary.wiley.com/doi/pdf/10.1111/1365-2435.13273 |
Summary: | Abstract Variation in offspring development is expected to be driven by constraints on resource allocation between growth and maintenance (e.g. thermoregulation). Rapid post‐natal development decreases predation risk to offspring, while inclement weather likely prolongs development. For taxa with parental care, parental behaviour may partially buffer offspring against extrinsic drivers like predation risk and severe weather. Using a 7‐year dataset from an alpine population of horned lark Eremophila alpestris , a ground‐nesting songbird in northern British Columbia, Canada, we investigated multiple potential drivers of variation in the duration of incubation and nestling development. Using path analysis, we evaluated the direct effects of weather, predation risk and parental care on offspring development, as well as indirect developmental “carry‐over” effects of conditions during incubation on the nestling period. Nestling period duration varied by nearly 100% (7–13 days) and incubation duration by 40% (10–14 days). Cold ambient temperatures late in the nestling period prolonged development by 1 day for every 2 days below 10°C, particularly when combined with heavy precipitation. Rapid nestling development was associated with high predation risk, and prolonging development incurred a nest survival cost (–2.3% per day). Females in good condition created nest environments that promoted rapid nestling development periods (average = 8–9 days) compared to poor condition females during harsh, early‐season conditions (10–11 days), indicating parental buffering capabilities against environmental constraints. Fledging age was weakly correlated with incubation duration ( r = –0.21) suggesting minimal developmental carry‐over effects. Given high nest predation risk, immediate fitness benefits can be derived by overcoming environmental constraints and reducing development time. While predation risk was influential, inclement weather and maternal condition had stronger effects on variation in offspring development. Addressing ... |
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