Cinnamomum cassia United Kingdom, and India is Chinese cinnamon. "Indonesian cinnamon" ("C. burmannii") is sold in much smaller amounts. Chinese cassia is produced in both China and Vietnam. Until the 1960s, Vietnam was the world's most important producer of Saigon cinnamon, which has a higher oil content , and consequently has a stronger flavor. Because of the disruption caused by the Vietnam War, however, production of Indonesian cassia in the highlands of the Indonesia island of Sumatra was increased to meet demand. Indonesian cassia has the lowest oil content of the three types of cassia, so commands the lowest price. Chinese cassia
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