Spice spices. Spices were among the most demanded and expensive products available in Europe in the Middle Ages, the most common being black pepper, cinnamon (and the cheaper alternative cassia), cumin, nutmeg, ginger and cloves. Given medieval medicine's main theory of humorism, spices and herbs were indispensable to balance "humors" in food, a daily basis for good health at a time of recurrent pandemics. In addition to being desired by those using medieval medicine, the European elite also craved spices in the Middle Ages. An example of the European aristocracy's demand for spice comes from the King of Aragon, who invested
Cassia crossbill It is believed that crossbills used the public information of different calls to forage. This eventually led to assortative flocking when crossbills would follow vocalizations that would provide them the easiest route to food. This can be another mechanism to how the Cassia crossbill diverged from the red crossbill. The Cassia crossbill and the other red crossbill call types will strongly associate with their own call types. Between 2001 and 2006, less that 1% of Cassia crossbills paired with other call types. Compared to the red crossbill call types, which are opportunistic breeders throughout most of the year, the Cassia