If you happen to be outside when a flock of grackles arrives, you may want to take shelter! It may rain acorns!
While we usually think of grackles as feeding in fields and on the ground, they also dine in trees. While most of the grackles were in the limbs, some were also foraging on the ground underneath, picking up fallen nut pieces. It was the nut pieces with their serrated edges that intriqued me. I wondered how they were cracking them open.
A. J. Marshall, Biology and Comparative Physiology of Birds, Vol 1: The Common Grackle (Quiscalus) has a hard keel projecting downward from the horny palate and regularly uses this in opening acorns or cracking corn.
Birds of North America/Common Grackle: Bill has hard, internal keel projecting downward from horny palate, which is sharper and more abrupt anteriorly. This keel extends below level of tomia [toothed projections along edge of beak] and is used as sawing adaptation to open acorns, which are often completely scored around shorter diameter and then cracked by adduction.
You may also enjoy these bird behavior posts:
Tail Signals from a Spruce Grouse
For the Love of It...
...the sage sees heaven reflected in Nature as in a mirror, and he pursues this Art, not for the sake of gold or silver, but for the love of the knowledge which it reveals.