Seed and color preferences of wild carrion crows
Data files
Jun 17, 2025 version files 10.94 KB
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colors.csv
3.47 KB
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README.md
1.89 KB
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seeds.csv
5.58 KB
Abstract
Birds can cause significant damage to agricultural fields, notably in Europe, where corvid species like carrion crows (Corvus corone) and rooks (Corvus frugilegus) target spring crops, posing challenges for conservation and wildlife management. Among targeted crops, sunflower and maize suffer the highest levels of damage from corvids’ foraging. While both lethal and non-lethal strategies are employed to mitigate bird damage, their effectiveness is limited and context-dependent. Consequently, there is growing interest in identifying natural bird repellents. To improve our understanding of corvid food selection and explore potential non-lethal management strategies, we conducted (1) cafeteria trials with five common seed types (maize, sunflower, soy, pea, and wheat) and (2) two-choice color tests with maize seeds in four colors (blue, green, orange and red) on an urban population of carrion crows accustomed to human presence. Results indicated a marked preference for sunflower and wheat, while soy and pea were largely avoided, and maize was moderately consumed. The crows also demonstrated a preference for green-colored maize over blue, orange, red, and natural maize seeds. These findings suggest that strategic planting of preferred crops like wheat alongside sunflower or maize may help mitigate damage. Further, incorporating colors into repellent seed coatings could reinforce the aversive learning process in birds, although color may play a less significant role in food selection when seeds are sown.
Reproducibility data for the manuscript "Seed and color preferences of wild carrion crows from cafeteria experiments", contains data and R script used in the main analysis.
Study aim:
- SEEDS
- Determine the seed types that wild crows prefer using a using a negative binomial mixed-effects model (NBMM)
- COLORS
- Test if they display a particular aversion for a given color using a GLM with binomial error structure
Data Description
seeds.csv
.csvfile with seeds' dataset , contains the following variables:$ID: test ID$date$n_indiv: number (in categories) of individuals present at a test when available$type: seed species; Wheat="B",Maize="M",Pea="P",Soy="S",Sunflower="T"$n_cons: number of consumed seeds$ratio_cons: proportion of consumed seeds$total_cons: total of consumed seeds per test ID$julian: julian date
colors.csv
.csvfile with colors' dataset , contains the following variables:$ID: test ID$date$duration: test duration when available$n_indiv: number of individuals present at a test when available$type: maize color; Blue="B",Green="G",Red="R",Orange="O"$nat_cons: number of natural maize seeds consumed$colour_cons: number of colored maize seeds consumed$total_cons: sum of colored and natural maize seeds consumed by crows$ratio_col_tot: proportion of colored seeds consumed$julian: julian date$julianscale: scaled julian date
Code
color_seed_code.R- R script for calibrating generalized linear models depicted in the manuscript, estimating marginal effects and, computing pairwise comparison of mean estimated parameters; and their associated figures.