As you can imagine, more acorns means good eating for herbivores such as chipmunks, squirrels, turkey and deer. Squirrels not only have a lot to eat, but they also help the tree to disperse its seeds. Gray squirrels bury their acorns in a variety of different places and then only recover some. These forgotten seeds often grow into saplings. In essence they are planting the seeds for the oaks.
Obviously, there are pros and cons for many natural phenomena, depending on your species and perspective. Scientists have linked larger Lyme disease carrying tick populations to years with small acorn crops. A good mast year in the northeast can lead to a boom in the population of white-footed mice, whereas a meager crop causes a big drop in the mouse population. White-footed mice are the preferred host for the black-footed tick which is very good at carrying and transmitting Lyme disease. When the population drops, the ticks are forced to find other hosts- including us. This was very clear after the huge mast crop in 2010. The mouse population sky-rocketed, then the following year the acorn crop was practically non-existent. The subsequent mouse population crash caused the potential for an influx of Lyme disease that year. Many believe that the tick population has only to do with the weather, but again, there are many factors at work in the complex natural world.
Regardless of the larger food web implications of raining acorns, it's probably best to duck and cover this fall if you venture out under the oak trees- they come down pretty fast!
Tree Activities and Resources
Mast Tree Network
Arbor Day Tree ID online field guide
Arbor Day Tree ID lesson plan (grades 4-12)
Project BudBurst- Citizen Science Project
Acorn Craft Ideas
Acorn Science Story for kids- Highlights magazine