Human-Wildlife Interactions (Feb 2017)
Feed Depredation by European Starlings in a Kansas Feedlot
Abstract
Confinement cattle-feeding operations have been associated with large populations of starlings (Sturnus vulgaris) during the winter months. Starlings can eat nearly 1 kg each of feed per month (Besser et al. 1968). In the first of our 2 studies, we evaluated feed selection and feed depredation by starlings using 5 concentrate-based cattle finishing diets. Four diets evaluated were in traditional meal-type form, and 1 diet was an extruded pellet. We placed rations into a section of the feed trough that we made accessible to starlings but not to cattle. Of the original 13.6 kg of steam-flaked corn and alfalfa hay ration placed into the feed trough at 0750 hours, only 1.9 kg (P < 0.05) of residual feed was recovered after starlings returned to their evening roost. Starlings preferentially selected steam-flaked corn (i.e., starch), thereby concentrating the crude protein and crude fiber fractions (P < 0.04) in residual feed. We observed similar trends for feed disappearance for the other meal-type rations. However, crude protein content was similar (P ≥ 0.10) between fresh and residual feed for dry-rolled corn and alfalfa hay diet and for steam-flaked corn and corn silage diet. Quantity and chemical composition between the fresh and residual extruded pellets were similar (P ≥ 0.57). In Experiment 2, the amount of feed delivered increased 36% for cattle (n = 13) that were fed traditional meal-type ration compared to cattle (n = 13) that were fed extruded pellets during a period of severe starling infestation. Following seasonal dispersal of starlings in early March, feed deliveries of traditional meal-type ration decreased to prestarling levels, while feed deliveries of extruded pellets remained unchanged. Starlings consumed 2,327 kg of feed from troughs with a total value of $563 throughout a period of 47 days, increasing daily cost of production by approximately $0.92 per feedlot animal.
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