## 4 Discussion  
As reported in the Materials and Methods section, several samples showed double signals in the electropherogram and therefore were not included in the haplotype counts as described by [PERSON] and colleagues [45]. This condition is presumably caused by heteroplasmy, i.e., the co-occurrence of different mtDNA haplotypes within the same  
Figure 8: Maximum Likelihood performed using the Jukes–Cantor model. The percentages of replicate trees in which the associated taxa clustered together in the bootstrap test (500 replicates) are shown next to the branches [44]. The tree is drawn to scale with branch lengths in the same units as those of the evolutionary distances used to infer the phylogenetic tree. Codon positions included were 1 st + 2 nd + 3 rd + Noncoding for 552 positions in the final dataset. individual. This condition can stem from several causes, including somatic or germline mutations or mitochondrial paternal leakage [46], a phenomenon already described within the Genus [45]. In this case, each double signal was visually scanned, and the two bases called by the sequencer were always typical of two of the already known haplotypes. These phenomena may have originated with hybridization, either between different species or subspecies, well documented in the _Microtus_ Genus [5, 47, 48]. In the Montefalco population, both the genetic variability and the frequency of heteroplasmic individuals are very high. The differentiation of some individuals of this population, if compared to other _Microtus_ genetic data from Italy, is well-supported by the presence of unique mutations never reported before. Furthermore, the mutations are not attributable to known haplotypes of _M. savii_ or _M. brachycercus_, even though these individuals seem phylogenetically related to the _M. savii_ complex. Literature analysis revealed a high variability in haplotype numbers present in different sampling pools of the _Microtus_ species. Data ranged from several haplotypes, each represented by a few individuals [49, 50], to a small number of haplotypes, each represented by many individuals [45, 51]. The number of different sequences is higher than those already documented for congeneric species at local geographic scale [45, 51] and might be due either to the coexistence of different genetic pools in the same area or to the sampling method. In fact, samples from each site could be gathered all around the owls' hunting grounds that may extend several miles from their roots [52]. As suggested by some authors [19, 53, 54, 55], the analysis of small mammal remains recovered from raptor pellets offers many resources for several kind of studies. Our results confirm the presence of _M. savii_ in Umbria, as previously reported by [PERSON] and [PERSON] [56], whereas no solid data were found to support the presence of _M. brachycercus_, which shows the northernmost distribution near the regional border. Generally, a greater value of the anterior loop breadth on the first lower molar is a feature that is typical of _M. brachycercus_[57]. Therefore, the morphological analyses performed on the Montefalco subsample gave reasons to believe that individuals of _M. brachycercus_ were present well above their northernmost limit of distribution. The morphometric findings were not supported by genetic data that did not support the morphological species identification but highlighted the presence of a population of _M. savii_, which presented an array of mutations that distanced the studied samples from already known _M. savii_ haplotypes. This peculiar biodiversity might stem from the different partitioning of voles' home ranges that are small when compared to owls' hunting grounds. [PERSON] and [PERSON] [58], using radiotelemetry data, found significant differences in the habitat use of field voles (_Microtus agretis_ [PERSON] 1758) with females being more philopatric than males that had home ranges five times wider. Likewise, _A.