van Oordt Francis, Silva Jaime, Patterson Allison, Elliott Kyle H
Department of Natural Resources, McGill University, Montreal, QC, Canada, H9X 3V9.
Universidad Nacional Agraria La Molina, 012 La Molina, Lima, Peru.
J Exp Biol. 2024 Nov 15;227(22). doi: 10.1242/jeb.249555. Epub 2024 Nov 20.
Daily energy expenditure (DEE) is the result of decisions on how to allocate time among activities (resting, commuting and foraging) and the energy costs of those activities. Dynamic body acceleration (DBA), which measures acceleration associated with movement, can be used to estimate DEE. Previous studies of DBA-DEE correlations in birds were carried out on species foraging below their thermoneutral zone, potentially decoupling the DBA-DEE relationship. We used doubly labelled water (DLW) to validate the use of DBA on plunge-diving seabirds, Peruvian boobies (Sula variegata), foraging in waters above their thermoneutral zone (>19°C). Mass-specific DEEDLW in boobies was 1.12 kJ day-1 g-1, and higher in males than in females. DBA alone provided the best fitting model to estimate mass-specific DEEDLW compared with models partitioned per activity and time budget models. Nonetheless, the model parametrizing activity at and away from their onshore breeding colony was the most parsimonious (r=0.6). This r value, although high, is lower than that of all other avian studies, implying that temperature is not the main cause of DBA-DEE decoupling in birds. Time at the colony (∼80% of the day) was the largest contributor to DEE as it was the most time-consuming activity and involved nest defence. However, foraging was the most power-consuming activity (4.6 times higher activity-specific metabolic rate than resting at the colony), and commuting flight was higher than in other gliding seabirds. In short, DBA alone can act as a proxy for DEE, opening avenues to measure the conservation energetics of this seabird in the rapidly changing Peruvian Humboldt Current system.
每日能量消耗（DEE）是关于如何在各项活动（休息、通勤和觅食）之间分配时间的决策以及这些活动的能量消耗的结果。动态身体加速度（DBA）用于测量与运动相关的加速度，可用于估计DEE。此前关于鸟类DBA与DEE相关性的研究是在低于其热中性区觅食的物种上进行的，这可能会使DBA与DEE的关系脱钩。我们使用双标水（DLW）来验证DBA在潜入水中觅食的海鸟秘鲁鲣鸟（Sula variegata）上的应用，这些鸟在高于其热中性区（>19°C）的水域觅食。鲣鸟的单位体重DEE（DLW法）为1.12 kJ·天⁻¹·克⁻¹，雄性高于雌性。与按活动划分的模型和时间预算模型相比，仅DBA就能提供最适合估计单位体重DEE（DLW法）的模型。尽管如此，将在岸上繁殖地及其周边的活动进行参数化的模型是最简洁的（r = 0.6）。这个r值虽然较高，但低于所有其他鸟类研究中的值，这意味着温度不是鸟类中DBA与DEE脱钩的主要原因。在繁殖地的时间（约占一天的80%）是DEE的最大贡献因素，因为它是最耗时的活动且涉及巢穴防御。然而，觅食是最耗能的活动（特定活动代谢率比在繁殖地休息时高4.6倍），并且通勤飞行比其他滑翔海鸟更高。简而言之，仅DBA就能作为DEE的替代指标，为在快速变化的秘鲁洪堡洋流系统中测量这种海鸟的能量守恒开辟了途径。
