Data from: Social foragers adopt a riskier foraging mode in the centre of their groups

Foraging in groups provides many benefits that are not necessarily experienced the same way by all individuals. I explore the possibility that foraging mode, the way individuals exploit resources, varies as a function of spatial position in the group, reflecting commonly occurring spatial differences in predation risk. I show that semipalmated sandpipers (Calidris pusilla), a social foraging avian species, tended to adopt a riskier foraging mode in the central, more protected areas of their groups. Central birds effectively used the more peripheral group members as sentinels, allowing them to exploit a wider range of resources within the same group at the same time. This finding provides a novel benefit of living in groups, which may have a broad relevance given that social foraging species often exploit a large array of resources.

群体觅食可带来诸多收益，但不同个体所获得的收益并不完全一致。本研究探讨了觅食策略——即个体开发利用资源的方式——会随群体内空间位置发生变化的可能性，该变化反映了捕食风险在空间层面普遍存在的差异。研究表明，社会性觅食鸟类半蹼滨鹬（*Calidris pusilla*）在群体中央更为安全的区域时，往往会采用风险更高的觅食策略。群体中的中央个体实际上将外围同伴作为哨兵，借此能够同时在同一群体内开发利用更广泛的资源。这一发现为群体生活提供了一种全新的收益维度；鉴于社会性觅食物种通常会开发利用大量多样的资源，该结论或许具备广泛的研究与应用相关性。