Foley Madeleine, Lato Kimberly A, Fuirst Matthew, Veit Richard R, Cerrato Robert M, Thorne Lesley H
School of Marine and Atmospheric Science, Stony Brook University, Stony Brook, NY, USA.
Birds Canada, 115 Front Road, Port Rowan, ON, Canada.
Mov Ecol. 2025 Feb 1;13(1):5. doi: 10.1186/s40462-025-00531-y.
Temporal and spatial predictability of food resources are critical to the foraging efficiency of central place foragers. While site fidelity is often assessed in this context, route fidelity, or the repeated use of the same path while traveling, and temporal aspects of habitat predictability have received less attention. We examined how the use of urban, coastal, and offshore habitats influenced spatiotemporal predictability in the foraging patterns of herring gulls (Larus argentatus) and great black-backed gulls (L. marinus). Since gulls show higher site fidelity when foraging in urban habitats, we predicted that these trips would also show higher route fidelity. Similarly, we predicted that gulls foraging in coastal habitats would adapt the timing of foraging trips relative to tides.
We analyzed GPS tracks of herring gulls (n = 79) and great black-backed gulls (n = 37)-between 2016-2022 from four nesting colonies whose surrounding areas varied in their degree of urbanization. Fréchet distance, which is defined as the repeated use of the same path while traveling, was used to assess route fidelity, within colonies and between habitat types. We also compared the consistency of foraging trip timing relative to tidal stage and day of week, respectively, across habitat types.
Neither herring nor great black-backed gulls showed higher route fidelity in urban habitats. Herring gulls showed direct travel between urban foraging sites but revisited sites in different orders, suggesting that a mosaic map may be used to navigate between known urban foraging sites. Herring and great black-backed gulls that foraged at coastal sites exhibited patterns in trip timing in relation to the tidal cycle, with foraging primarily occurring at or around low tide. Herring gulls in urban environments foraged more on Fridays and weekends, possibly due to increased or altered human activities on these days.
Our results demonstrate the importance of spatial memory and spatiotemporal predictability of gull foraging habitats and highlight the extent to which gulls adjust their movements based on their foraging habitats.
食物资源的时空可预测性对于中心地觅食者的觅食效率至关重要。虽然在这种情况下经常评估地点忠诚度，但路线忠诚度，即在旅行时重复使用同一路径，以及栖息地可预测性的时间方面受到的关注较少。我们研究了城市、沿海和近海栖息地的利用如何影响银鸥（Larus argentatus）和大黑背鸥（L. marinus）觅食模式的时空可预测性。由于海鸥在城市栖息地觅食时表现出更高的地点忠诚度，我们预测这些行程也会表现出更高的路线忠诚度。同样，我们预测在沿海栖息地觅食的海鸥会根据潮汐调整觅食行程的时间。
我们分析了2016年至2022年间来自四个筑巢群体的银鸥（n = 79）和大黑背鸥（n = 37）的GPS轨迹，这些群体周围地区的城市化程度各不相同。弗雷歇距离被定义为旅行时同一路径的重复使用，用于评估群体内部和栖息地类型之间的路线忠诚度。我们还比较了不同栖息地类型在相对于潮汐阶段和星期几的觅食行程时间上的一致性。
银鸥和大黑背鸥在城市栖息地均未表现出更高的路线忠诚度。银鸥在城市觅食地点之间直接飞行，但以不同顺序重访地点，这表明可能使用镶嵌地图在已知的城市觅食地点之间导航。在沿海地点觅食的银鸥和大黑背鸥在行程时间上表现出与潮汐周期相关的模式，觅食主要发生在低潮时或低潮前后。城市环境中的银鸥在周五和周末觅食更多，这可能是由于这些日子人类活动增加或改变。
我们的结果证明了海鸥觅食栖息地的空间记忆和时空可预测性的重要性，并突出了海鸥根据觅食栖息地调整其活动的程度。
