Quantification of the Starling Population, Estimation and Mapping of the Damage to Olive Crops in the Apulia Region

Abstract

The presence of wildlife in areas with a high concentration of farming activities can create a conflict between conservation objectives and productive purposes. Near Brindisi (Apulia, S-E Italy), a substantial amount of cash compensation claims for damages reported by local farmers and attributed to starlings (Sturnus vulgaris) has been registered. The aim of this study was to quantify the starling population wintering in the Apulia region, in order to assess the potential damage to crop production caused by this species. Our analysis was conducted over three years and included three main activities: a study of starling abundance and movements, the identification of areas and crops affected by damages, and a determination of the damage to the agricultural system in terms of quantity and concentration (heatmap). The study showed a loss of expected production that was coherent with the eating capacity of starlings wintering in the region. This means a loss, in terms of gross profitable production, of around 550,000 euros concentrated in a few narrow areas close to the roosts. Results on species behavior, damage quantification, and mapping are useful elements aimed to activate trade-off measures to preserve production and protection objectives, and to allow policymakers to address enforcement interventions and to establish parameters for financial compensation.

Recent Northward Expansion of a Passerine Bird Species, Brownish-Flanked Bush Warbler (Horornis fortipes)

“…The European Starling (Sturnus vulgaris), originally native to Europe and North Africa, was introduced to the Americas in the late 19th century, where it rapidly established colonies [16]. The species causes considerable damage to local agriculture in Italy [17], and has been found to pose a disease risk to livestock in the U.S. [18]. Studies on the island of Hawaii have shown that exotic birds alter the plant seed dispersal patterns [19].…”

Seasonal Use of Dairies as Overnight Roosts by Common Starlings (Sturnus vulgaris)

“…Common Starlings are flexible in choosing a location to establish a roost. Roost site locations are often concentrated in farmland that heavily fragments natural areas and contains a variety of crops as possible food sources, but they can also be found near population centers [25][26][27] Roosting site fidelity has been reported to be between 48% and 95%, with fidelity increasing with the age of the bird and availability of feed near the roosting site [28][29][30]. This pattern of roost site fidelity is also seen on a smaller scale, with starlings preferring to stay in one roost site overnight unless their energetic needs increase due to cold weather or a lack of an easily available food source [31].…”