Birds

Birds was founded on September 2020 [...]

Corvids exhibit avoidance behaviour when foraging in the presence of potentially risky stimuli, yet it remains unclear how stimulus characteristics influence the strength of such responses. In this paper, we present wild-caught Large-billed Crows (Corvus macrorhynchos) with five conditions: no visual stimulus, a cardboard box (non-biological, stationary), an immobile owl decoy (biological, stationary), a continuous-motion owl decoy (biological, moving), and a sensor-activated-motion owl decoy (biological, moving, and sudden). Avoidance was quantified using feeding latency, landing frequency, total time spent in the feeding area, and food consumption. Compared with the condition with no visual stimulus, the presence of any visual stimulus elicited increased latency, indicating that crows detect and respond to objects near food. Among the four objects, the sensor-activated-motion owl decoy produced stronger avoidance responses of the crows than the non-biological and stationary object (cardboard box). This indicates that they evaluate not only the presence of an object but also its motion characteristics and/or perceived biological cues when adjusting their foraging behaviour. Although sample size and individual variation impose limitations, these findings suggest that both the presence of visual stimuli and/or the complexity of their appearance play key roles in shaping avoidance behaviour in corvids.

Parasitic infections represent an important health challenge in falcons (Falconidae), where they may negatively influence survival, reproduction, and performance. This study is the first investigation in Serbia assessing the prevalence and diversity of endoparasites in captive falcons, with special emphasis on Serratospiculum spp. A total of 145 live birds (hybrid falcon, Falco peregrinus, F. cherrug, F. rusticolus) and 1 dead individual were examined. Diagnostic procedures included necropsy, coprological analysis, and molecular detection. Endoparasites were confirmed in 55.2% of fecal samples. The most frequent were Caryospora spp. (41.4%), followed by Porrocaecum spp. (18.6%), Capillaria spp. (3.4%), and Serratospiculum spp. (2.8%). Statistically significant differences were observed between sexes, locations, and preventive health management. Falcons kept under preventive measures showed a markedly lower prevalence compared with those lacking such care. These findings highlight the persistent occurrence of endoparasites in Serbian falcons and underscore the importance of preventive programs. Regular deworming, strict hygiene, and vector control represent essential strategies for minimizing infections, particularly of Serratospiculum spp., which poses a serious respiratory health threat.