Each autumn, American Crows (Corvus brachyrhynchos) in the Central Valley of California, USA, forage heavily on walnut trees (Juglans regia) planted along residential streets. Some of these nuts are dropped onto roads and cracked for immediate consumption, but others are carried away from foraging sites to be cached. I quantified caching behavior to understand its importance in corvid natural history and the potential for corvids to disperse large tree seeds. Crows cached an estimated 2000 walnuts/km2/yr in agricultural fields 1–2 km away. Most (73%) crows that found a walnut left the foraging site with it, and most (77%) of these crows cached their nuts. Some crows carried walnuts long distances (e.g., 5% of nuts foraged from trees were carried >2 km) and buried them in unforested habitat; this indicates that crows may be agents of tree seed dispersal. Transporting and caching a nut required approximately 10 min and increased the likelihood of it being stolen, relative to a nut eaten immediately at the walnut tree. Without knowing the timing and rates of recovery, it is unclear when and to what degree American Crows benefit from walnut-caching, which has not been previously described in this species.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 76 • No. 1