Raven food calls indicate sender’s age and sex User AstuteJudo, in the Zoology subreddit, 13 Mar 2018
Raven food calls indicate sender’s age and sex User ScurfyBun, in the Animal Science - health, biology, and genetic engineering/modification (GMO) subreddit, 13 Mar 2018
Raven food calls indicate sender’s age and sex User QuietCakeBionics, in the Reddit Science subreddit, 13 Mar 2018