Quality over size: acorn preference in Eurasian Jays (Garrulus glandarius)
摘要
Seed traits play a crucial role in granivore foraging decisions and subsequent seed dispersal. We examined the influence of acorn quality and size on seed removal by Eurasian Jays (Garrulus glandarius), key seed dispersers of oaks. In the field experiment, we offered Pedunculate Oak (Quercus robur) acorns varying in quality (sound versus defective) and size (small versus large). We additionally monitored acorn removal using camera traps. In the final seed removal analysis, Jays preferred sound and small acorns. In turn, in the temporal persistence analysis, Jays opted for sound acorns regardless of size while defective large acorns were least preferred. Our results demonstrated that Jay foraging decisions were primarily influenced by acorn quality and secondarily by size. This has potential implications for oak recruitment under future climate change scenarios with more frequent and intense droughts.