The reasons jelly beans were used was it was a few weeks after Easter. I think a couple of us when to the local Hills Department store and raided the candy section two days after the holiday, picking up bags upon bags of them.
But, man cannot exist on jelly bean alone, so we started tossing them to the squirrels.
The resulted in the Great BGSU Squirrel War of 1991. After a couple of them got the taste, others around the campus heard and started gathering around our place. Throwing out a couple of jelly beans could result in total chaos.*
But, alas, jelly beans are not eternal and our entertainment was short lived.
*NOTE: No squirrels were actually hurt in this story. We also gave them healthy stuff, like various nuts, crackers and Ramon Noodles.