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Table 1 Frequency of occurrence and biomass of 120 long-eared owl pellets from wintering roosts in Janos, Chihuahua, México collected in 2007
| Prey | FR | FR% | Biomass (gr) | B% |
|---|---|---|---|---|
| Mammals | 135 | 95.74 | 11059 | 100 |
| Soricidae | 1 | 0.71 | 5 | 0.04 |
| Leporidae | 1 | 0.71 | 1002 | 9.06 |
| Desert cottontail (Sylvilagus audubonii) | 1 | 0.71 | 1002 | 9.06 |
| Cricetidae | 77 | 54.61 | 8924 | 80.69 |
| White-throated woodrat (Neotoma albigula) | 6 | 4.26 | 1035 | 9.36 |
| Southern grasshopper mouse (Onychomys torridus) | 8 | 5.67 | 200 | 1.81 |
| North american deermouse (Peromyscus maniculatus) | 2 | 1.42 | 45 | 0.41 |
| Tawny-bellied cotton rata (Sigmodon fulviventer) | 22 | 15.60 | 2398 | 21.68 |
| Hispid cotton rat (Sigmodon hispidus) | 17 | 12.06 | 2848 | 25.75 |
| Cotton rat (Sigmodon sp.) | 22 | 15.60 | 2398 | 21.68 |
| Heteromyidae | 39 | 27.66 | 1129 | 10.20 |
| Merriam's kangaroo rat (Dipodomys merriami) | 1 | 0.71 | 43 | 0.38 |
| Ord's kangaroo rat (Dipodomys ordii) | 4 | 2.84 | 292 | 2.64 |
| Banner-tailed kangaroo rata (Dipodomys spectabilis) | 4 | 2.84 | 534 | 4.83 |
| Kangaroo kat (Dipodomys sp.) | 1 | 0.71 | 43 | 0.38 |
| Silky pocket mouse (Perognathus flavus) | 29 | 20.57 | 218 | 1.97 |
| Unidentified rodents | 17 | 12.06 | - | - |
| Unidentified birds | 1 | 0.71 | - | - |
| Insects | 4 | 2.84 | - | - |
| Orthoptera: Acriididae | 3 | 2.13 | - | - |
| Coleoptera | 1 | 0.71 | - | - |
| Vertebrates | 137 | 97.16 | - | - |
| Invertebrates | 4 | 2.84 | - | - |
