Colouration and flavouring of sunflower seeds affect feeding behaviour in urban Carrion crows (Corvus corone): A preliminary study

Abstract

The damage caused to crops by wildlife, particularly birds, represent a major challenge for farmers. This study aimed to preliminarily assess feeding behaviour of Carrion crows (Corvus corone) on sunflower seeds in field conditions. The crows’ preferences were tested along a visual cue (seed colour: blue vs. uncoloured) and a taste cue (pepper coating vs. unflavoured). The experiments were carried out in two sessions interspersed by several weeks. For each session, the influence of seed colours on birds’ preferences (n = 200 uncoloured, n = 200 blue) was assessed on day 1, and the influence of seed pepper coating (n = 200 pepper coated, n = 200 unflavoured seeds) was assessed on days 2 and 3. Every day, the remaining seeds within each furrow were counted at 4 after the start of the assay. Throughout the experiments, the only wild birds seen consuming seeds were Carrion crows (Corvus corone). In each session, the birds consumed significantly less blue seeds than controls (p < 0.05). However, blue seed intake significantly increased between the 2 sessions. The birds thus appear to rely on sight to select sunflower seeds. Otherwise, a significant effect of pepper coating arose in session 2, with birds consuming less pepper-coated seeds than unflavoured seeds (p < 0.0001). This intake of pepper seeds was significantly higher in session 1 than in session 2. Therefore, coating the seeds with a pungent irritant may induce reluctance. These assays confirm that Carrion crows are sensitive to the colour and flavour of sunflower seeds, rapidly learn and get used to visual and chemosensory novelty.