Barn Owl pellets were collected across Georgia between 2023 and 2025 from 34 locations situated in five administrative regions: Adjara, Imereti, Kakheti, Kvemo Kartli, and Samegrelo-Zemo Svaneti (Fig. 1). Sampling sites were associated with known roosting and breeding areas of dispersing Barn Owls.

Fresh pellets were characterized by a glossy, lacquered surface with a blackish tint due to salivary coating, consistent with descriptions by Mikusek (2005) and Poprach (2010).

To ensure biosafety and facilitate dissection, all pellets were sterilized by oven-baking at 160°C for 40 minutes, following the protocol of Orosz-Coghlan et al. (2022), and then soaked in warm water. A total of 6627 prey items were extracted and identified to the lowest possible taxonomic level (Table 1).

Figure 1. 

A map of Georgia with 34 sites where Barn Owl (Tyto alba) pellets have been collected in 2023–2025.

Prey remains extracted from Barn Owl pellets included mammals, birds, amphibians, reptiles, and invertebrates. Mammals (Rodentia, Eulipotyphla, Chiroptera, Carnivora) were identified using standard taxonomic keys and monographs (Pucek 1981; Kryštufek and Vohralík 2001, 2005, 2009; Aulagnier et al. 2009; Zaitsev et al. 2014; Tembotova 2015; Kryštufek and Shenbrot 2022, 2025; Russo 2023). Species nomenclature followed recent national checklists (Bukhnikashvili et al. 2023; Kandaurov et al. 2023), with the only exception being the use of Crocidura gueldenstaedtii instead of Crocidura suaveolens, as used in earlier and modern classifications (Bukhnikashvili 2004; Gazzard and Kryštufek 2024).

Due to local morphological variation in Caucasian rodents, standard identification methods were sometimes insufficient, and additional references were consulted. For example, distinguishing Microtus socialis required intact skulls and ratios of rostrum height and interorbital constriction to condylobasal length, along with proportionally large auditory bullae (Vinogradov and Gromov 1952; Kryštufek and Kefelioğlu 2001). Although Microtus rossiaemeridionalis has recently been recorded in Georgia (Maglakelidze et al. 2024), its morphological similarity to M. obscurus necessitated treating all specimens as M. obscurus in the absence of DNA data.

Cranial features were used to separate Rattus rattus and R. norvegicus, mainly based on molar shape (Pucek 1981; Yiğit et al. 1998; Kryštufek and Vohralík 2009).

Identification of Pine Voles (Microtus majori) relied on specific M1 patterns of the lower mandible, while M. subterraneus was excluded based on its known distributions; in addition, M. daghestanicus was excluded due to its preference for high-altitude habitats, whereas all our data were collected in lowland areas (Çolak et al. 1998; Kryštufek and Vohralík 2004; Aulagnier et al. 2009).

In many cases, Mus and Apodemus specimens were too fragmented for species-level identification. For Mus, separation of M. musculus and M. macedonicus used zygomatic index (Zagorodniuk 2002; Çolak et al. 2006; Kryštufek and Vohralík 2009), though this was not always conclusive due to damaged remains. Third molar ratios provided limited accuracy. Apodemus species were identified to genus level unless diagnostic features (e.g., bullae or tooth row length) were intact, as overlapping morphotypes (e.g., A. ponticus, A. witherbyi) complicate identification (Darvish et al. 2014; Mohammadi et al. 2014; Okulova et al. 2018; Maglakelidze et al. 2024).

Bird remains were identified mainly from skulls (Brown et al. 2021; Drewitt 2024), using an osteological reference collection. Ulna shape was of limited diagnostic value (Panteleev 2005). As no published data exist on bird biomass in Georgia, we used mean body mass data from the Aras Bird Ringing Station in Türkiye, based on measurements of 2511 individuals collected in 2023–2024.

Amphibians and reptiles were not identified to species level; representative species (Hyla orientalis, Lacerta agilis) were used for biomass estimation (Shlyakhtin et al. 2019; Burraco et al. 2021). Invertebrate remains were identified by specialists (A. Seropian, A. Schröter, T. Stalling), and biomass was estimated using published mean weights, rounded to 1 g where necessary (Cornwell 1976; Meresman and Ribak 2020; Hendrix and Verdonschot 2021).

A total of 6627 prey items were extracted from Barn Owl pellets and identified to the lowest possible taxonomic level. Of these, 996 individuals originated from western regions (Adjara, Imereti, Samegrelo-Zemo Svaneti), and 5631 from eastern Georgia (Kakheti and Kvemo Kartli). By number and mass Rodentia prevail among other preys with 3528 individuals or 87726.7 g. The second largest group of mammals as preys is Eulipotiphla with 2985 individuals or 28037.9 g. The rest of animal groups estimate 114 individuals or 1749.1 g (Table 2).

Small mammals overwhelmingly dominated the diet: rodents accounted for 53% of all prey by number and 75% by total biomass, while shrews (Soricidae) comprised 45% by number and 23% by biomass. Together, these two groups made up 98% of total biomass (Fig. 2). Other vertebrates—bats, birds, amphibians, reptiles—and invertebrates were rare (Table 2).

Among 1099 unbroken pellets, length ranged from 21.6 to 81.0 mm (mean = 39.8 mm), and width from 14.6 to 45.9 mm (mean = 26.0 mm) (Fig. 3). Each pellet contained between 1 and 13 individual prey items (mean = 3.53) (Fig. 4). Only 6 pellets contained more than 10 prey items, with those dominated by small Soricidae. Altogether, 3883 prey items (58.6% of total) were recovered from intact pellets.

The pellet with the highest prey count (13 individuals) came from Poti (Samegrelo-Zemo Svaneti) and contained 11 Sorex volnuchini, 1 Neomys teres, and 1 Crocidura sp. Another highly diverse pellet from Shiraki (Kakheti) held 11 Crocidura sp.

Taxonomically, the Barn Owl diet in Georgia included representatives of five vertebrate classes and invertebrates (Fig. 5). Mammals dominated with 98.6% of prey by number, followed by birds (1.0%), and a combined 0.4% from amphibians, reptiles, and invertebrates.

Figure 2. 

Prey composition in the diet of Barn Owl (Tyto alba) in Georgia by: A: number of individuals, B: biomass (%).

Figure 3. 

Distribution of Barn Owl (Tyto alba) pellet dimensions (n = 1099).

Figure 4. 

Number of prey items per unbroken Barn Owl (Tyto alba) pellet (n = 1099).

Figure 5. 

Selected prey remains from Barn Owl (Tyto alba) pellets: A: Mus musculus; B: Decticus sp. (Orthoptera); C: Pipistrellus sp. (Chiroptera); D: Dryomys nitedula; E: Rodentia: Apodemus sp.; F: Crocidura gueldenstaedtii; G: Sorex volnuchini; H: Hirundo rustica; I: Micromys minutus; J: Talpa levanti.

Although rodents dominated the overall diet of Barn Owls in Georgia, notable geographic variation was observed. At sites with over 200 prey items (n=10) —indicating long-term owl presence—shrews (Soricidae) occasionally outnumbered rodents by number or biomass (e.g. Nazarlo, Chailuri, Poti) (Table 3). This pattern may reflect temporary declines in rodent populations, potentially driven by population cycles or pesticide use in agricultural areas.

These local deviations align with previous observations that Barn Owls exhibit selective opportunism, primarily preying on rodents when available (Tores et al. 2005). In other countries, high consumption of shrews by Barn Owls has also been reported, including Germany (Gurney 1876), Italy (Bose and Guidali 2001), Greece (Bontzorlos et al. 2005), and Turkey (Hoppe 1986). However, due to the absence of similar pellet studies in the Caucasus region, it remains unclear whether the patterns observed here are typical for the region or unique to Georgia.

Owl pellet content is representative for real proportions of the small mammal species in their communities at the open areas (Andrare et al. 2015). Pellet analysis also provided new insights into the distribution of several small mammal species in Georgia.

Pygmy White-toothed Shrew (Suncus etruscus). Previously known only from eastern Georgia (Buknikashvili 2004), this species was detected exclusively in Kvemo Kartli and Kakheti. The presence of 41 individuals suggests a more common and widespread status than previously assumed, corroborating recent regional observations (Kandaurov et al. 2023). Similar records of S. etruscus in owl pellets have been reported from southeastern Turkey (Coşkun and Kaya 2013).

Harvest Mouse (Micromys minutus). Historically reported from only seven western Georgian sites, mainly from older records (Bukhnikashvili et al. 2023), M. minutus was recorded here from Adjara and, for the first time, from eastern regions (Kvemo Kartli, Kakheti), with 89 individuals identified. These findings significantly extend its known range.

Transcaucasian Water Shrew (Neomys teres) and Caucasian Pygmy Shrew (Sorex volnuchini). Despite being widely distributed in Georgia (Buknikashvili 2004), both species were found only in pellets from the Poti region. This site—formerly a marshland and now a canal system with rich vegetation and no agriculture—likely supports suitable habitats. Their absence elsewhere likely reflects a sampling bias toward agricultural landscapes, which are less favorable for these species.

Brandt’s Hamster (Mesocricetus brandti). Only a single individual was recorded at Shiraki (Kakheti), a steppe habitat considered atypical for Barn Owl hunting. However, with the owl’s ongoing range expansion into suboptimal habitats, occasional predation on large desert rodents may become more frequent.

This study represents the first comprehensive analysis of the Barn Owl’s diet in Georgia, covering a wide geographic range and providing a dataset of over 6600 prey items identified from owl pellets. The overwhelming dominance of small mammals, particularly rodents and shrews, confirms that the Barn Owl functions primarily as a specialist predator on terrestrial micromammals, although its capacity to exploit other taxa—including birds, bats, amphibians, reptiles, and invertebrates—reflects opportunistic tendencies when primary prey availability fluctuates.

The high representation of rodents (53% by number and 75% by biomass) supports the hypothesis that Barn Owls may play a significant ecological role in regulating rodent populations in Georgia’s agricultural landscapes. This aligns with findings from other regions where Barn Owls are already integrated into pest management strategies. At the same time, the significant presence of shrews in certain areas and years suggests sensitivity to local prey dynamics, possibly influenced by natural population cycles or anthropogenic factors such as pesticide use.

From a faunistic standpoint, the study contributes valuable records for small mammal distribution in Georgia, including the easternmost confirmations of Suncus etruscus and previously undocumented occurrences of Micromys minutus in eastern regions. These results underline the utility of owl pellet analysis as a complementary method for biodiversity assessments, especially in understudied or inaccessible habitats.

The research also identifies several methodological and interpretative challenges, including species-level identification difficulties due to cranial damage or cryptic morphology, and the need for more detailed ecological data on the small mammal communities being preyed upon.

Going forward, a multi-seasonal and multi-year monitoring program, complemented by live-trapping and habitat assessments, would help clarify temporal prey fluctuations, reveal effects of agricultural practices, and further test the feasibility of using Barn Owls as a nature-based solution for rodent control. Such efforts could also enhance our understanding of the ecology of prey species, many of which remain poorly documented in Georgia.

Altogether. the Barn Owl emerges not only as a key predator with potential agricultural utility, but also as a valuable bioindicator and sampling tool for small mammal communities in the region. As Georgia continues to integrate biodiversity research into conservation and land-use planning, expanding the scope of such integrative studies is essential for promoting sustainable coexistence between wildlife and human activities.

The authors have declared that no competing interests exist.

No ethical statement was reported.

The preparation of this paper was carried out within the framework of the EU4Belarus SALT II program and funded by the European Union.

DK collected and desiccated Barn Owl pellets, conceived an idea of the paper and wrote the manuscript; ZJ was responsible for the collaboration between Ilia State University (Georgia) and University of Bialystok (Poland) to implement the project.

Denis Kitel https://orcid.org/0000-0002-5298-2611

Zurab Javakhishvili https://orcid.org/0000-0001-8909-1081

All of the data that support the findings of this study are available in the main text or Supplementary Information.