Dixon Mark D, Johnson W Carter, Adkisson Curtis S
Department of Horticulture, Forestry, Landscape and Parks, South Dakota State University, Brookings, SD 57007, USA, , , , , , US.
Department of Biology, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA, , , , , , US.
Oecologia. 1997 Jul;111(2):201-208. doi: 10.1007/s004420050226.
Blue jays (Cyanocitta cristata L.) are important consumers and dispersers of the nuts of oaks and other fagaceous trees in eastern North America. Acorns compose much of the jay diet, especially during the autumn when jays may consume or cache a significant portion of an acorn crop. However, jays do not appear to possess physiological adaptations for countering the protein-binding properties of secondary compounds (tannins) found in acorns. We offered captive blue jays a mixture of infested and uninfested pin oak (Quercus palustris Muenchh.) acorns to see if the birds would selectively consume nuts containing weevil larvae (Coleoptera: Curculionidae) as a protein supplement to a high-tannin, all-acorn diet. Acorns were X-rayed to determine infestation status and then offered to individual jays in an outdoor aviary. Jays handled, opened, and consumed uninfested nuts significantly more often than infested nuts, and use of infested nuts did not increase during continued exposure to a high-tannin diet.
冠蓝鸦（Cyanocitta cristata L.）是北美东部橡树和其他壳斗科树木坚果的重要消费者和传播者。橡子是冠蓝鸦饮食的重要组成部分，尤其是在秋季，此时冠蓝鸦可能会消耗或储存大量的橡子收成。然而，冠蓝鸦似乎没有针对橡子中次生化合物（单宁）的蛋白质结合特性的生理适应性。我们给圈养的冠蓝鸦提供了受虫害和未受虫害的沼生栎（Quercus palustris Muenchh.）橡子混合物，以观察这些鸟类是否会选择性地食用含有象鼻虫幼虫（鞘翅目：象甲科）的坚果，作为高蛋白、全橡子饮食的蛋白质补充。对橡子进行X射线检查以确定虫害状况，然后在室外鸟舍中将其提供给个体冠蓝鸦。冠蓝鸦处理、打开和食用未受虫害坚果的频率明显高于受虫害坚果，并且在持续接触高单宁饮食期间，对受虫害坚果的食用量并未增加。
