Blue Jays and Acorns
In fall, acorns begin to drop from oak trees. It is amazing to think that this little nut may someday grow into a mighty oak.
However, not all the seeds are viable. Some may become infested with a fungus or acorn weevils which lay their eggs inside the acorn. When the eggs hatch, the growing larvae feed on the nut.
To determine viability, acorns can be dropped into a bucket of water and those that sink have a fairly good chance of germinating.
It is reasonable to think the energetic squirrel is the biggest distributor of acorns. However, their dispersal is not as impressive as the blue jay. For centuries these birds have played a major role in scattering acorns and regenerating oak forests.
Blue jays have a fondness for the nuts and can transport them at astounding levels. They are known to carry off 100 acorns a day during harvest and a single jay may hide 3,000 – 5,000 nuts in one season.
While squirrels bury acorns only a few feet from the mother tree, blue jays can move the nuts up to three kilometers away. This cache of acorns is more likely to be buried in open areas where available light ensures favorable growing conditions for the new seedlings.
Another interesting adaptation is the blue jay’s ability to carry up to five acorns per trip. The bird accomplishes this by flying with three in its throat or “gular pouch”, one in its mouth, and one on the tip of its beak. The most amazing mark of genius, however, is that blue jays have the aptitude to preferentially select acorns that are most likely to germinate. They can tell a good nut from a bad nut and have been shown to discern fertile acorns with 88% accuracy.
Like other birds that hide and store food, such as chickadees and nuthatches, blue jays too have a remarkable ability to remember where they hide their cache and return later in the season to retrieve them. Of course, they don’t find all their buried nuts. Some get left where they are planted and these few may sprout and grow into a new oak.
Thank you, Brenda Gallagher, for this article!
