Sage Elspeth, Bouten Willem, van Dijk Walter, Camphuysen Kees C J, Shamoun-Baranes Judy
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090GE Amsterdam, the Netherlands.
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090GE Amsterdam, the Netherlands.
Sci Total Environ. 2022 Dec 15;852:157879. doi: 10.1016/j.scitotenv.2022.157879. Epub 2022 Aug 6.
The energy exchange between the Earth's surface and atmosphere results in a highly dynamic habitat through which birds move. Thermal uplift is an atmospheric feature which many birds are able to exploit in order to save energy in flight, but which is governed by complex surface-atmosphere interactions. In mosaic landscapes consisting of multiple land uses, the spatial distribution of thermal uplift is expected to be heterogenous and birds may use the landscape selectively to maximise flight over areas where thermal soaring opportunities are best. Flight generalists such as the lesser black-backed gull, Larus fuscus, are expected to be less reliant on thermal uplift than obligate soaring birds. Nevertheless, gulls may select flight behaviours and routes in response to or in anticipation of thermal uplift in order to reduce their transport costs, even in landscapes where thermal uplift isn't prevalent. We explore thermal soaring over land in lesser black-backed gulls by using high-resolution GPS tracking to characterise individual instances of thermal soaring and detailed energy exchange modelling to map the thermal landscape which gulls experience. We determine that lesser black-backed gulls are regularly able to undertake thermal soaring, even in a wet temperate landscape below sea level. By examining the relationship between lesser black-backed gull flight, thermal uplift and land use, we determine that built up areas, particularly towns and cities, provide thermal uplift hotspots which lesser black-backed gulls preferentially make use of, resulting in more opportunities for energy saving flight through thermal soaring.
地球表面与大气之间的能量交换形成了一个鸟类穿梭其中的高度动态的栖息地。热上升气流是一种大气特征，许多鸟类能够利用它来节省飞行能量，但其受复杂的地表 - 大气相互作用的支配。在由多种土地利用类型组成的镶嵌景观中，热上升气流的空间分布预计是不均匀的，鸟类可能会有选择地利用景观，以便在热气流上升机会最佳的区域上空实现飞行最大化。像小黑背鸥（Larus fuscus）这样的飞行通才，预计比专性翱翔鸟类对热上升气流的依赖程度更低。然而，即使在热上升气流不普遍的景观中，海鸥也可能会根据热上升气流或预期热上升气流来选择飞行行为和路线，以降低其运输成本。我们通过使用高分辨率GPS跟踪来描述热气流上升的个体实例，并通过详细的能量交换模型来绘制海鸥所经历的热景观，从而探索小黑背鸥在陆地上的热气流上升情况。我们确定小黑背鸥即使在海平面以下潮湿的温带景观中也能经常进行热气流上升。通过研究小黑背鸥飞行、热上升气流和土地利用之间的关系，我们确定建成区，特别是城镇和城市，提供了小黑背鸥优先利用的热上升气流热点，从而通过热气流上升实现节能飞行的机会更多。
