Tuning oral-bait delivery strategies for red deer in Mediterranean ecosystems

The current demographic expansion of red deer populations in the northern hemisphere has led to conflicts at the levels of health, the economy, and conservation. Potential tools for deer management include the delivery of contraceptives that impair reproduction in order to control populations or the delivery of treatments/vaccines in order to control health. To successfully implement these control strategies, it is necessary to develop suitable methods with which to deliver treatments to red deer in field settings. The objectives of this study were (i) to evaluate the specificity and palatability of three bait types—alfalfa, feed, and molasses-based—for red deer (Cervus elaphus) and (ii) to describe the constraints that limit or enhance the effectiveness of the bait deployment method—on the ground or in specific red deer feeders—for the oral delivery of treatments to red deer in Mediterranean ecosystems. Our results show that alfalfa baits are the least palatable but the most deer-selective type of bait, whereas feed and molasses baits are highly palatable but low specific (mean bait consumption rates on the ground were 0.811, 0.949, and 0.955, respectively). The appropriate season for oral treatments using alfalfa baits both on the ground and in deer feeders is late summer (mean bait consumption rate on the ground for alfalfa-based baits was 0.939 in summer period). These results indicate that alfalfa baits are sufficiently palatable and specific in summer for them to be an efficient means to deliver treatments to red deer in Mediterranean ecosystems.