This article shows for the first time that the vocal repertoire of European red deer males is not limited to rutting roars emitted during the reproductive period. It turned out that males on the farm, in the absence of females, can scream roars almost indistinguishable from rutting ones and outside the rutting period. In addition to non-rutting calls, we also described two new, previously unknown types of calls in male European red deer: the contact call and the lowing. Unlike roars, the males never made these calls in the presence of people, so the farm staff did not even suspect the existence of such calls in their deer. Contact cries and mooing of deer could only be recorded thanks to the use of an automatic sound recording device attached to the feeder and operating offline in the absence of people. Animals started calling when people left in the evening and stopped calling in the morning when people appeared on the farm. Thus, automatic devices make it possible to detect a part of the behavioral activity of farm animals that is hidden from people. Obviously, the presence of people (staff or researchers) can influence the vocal activity of farm animals and lead to the use of a depleted vocal repertoire.
The results of the study were published in the journal Animal Production Science: Volodin I.A., Gogoleva S.S., Garcia A.J., Landete-Castillejos T., Volodina E.V., 2023. Nocturnal chats of farmed animals: non-rutting vocalizations of male Iberian red deer Cervus elaphus hispanicus. Animal Production Science, v. 63.
