Camera-trap survey to detect free-ranging domestic cats and other mammals in Sierra de Aracena and Picos de Aroche Natural Park

Study Extent

Both surveys were carried out in the Natural Park of Sierra de Aracena and Picos de Aroche, located in the western part of Sierra Morena (N 37° 59′ 42″, W 6° 52′ 23″), in south-western Iberian Peninsula. The park has a total area of 186,795 ha distributed in small municipalities of agricultural-forestry-livestock tradition. Its altitude range (460–1055 m.a.s.l.), and the annual rainfall variability (700–1000 mm) creates a large number of different habitats and environmental conditions. The study area is dominated by a medium-sized carnivore guild. The most common carnivore species are red fox (Vulpes vulpes), European badger (Meles meles), Egyptian mongoose (Herpestes ichneumon), stone marten (Martes foina) and common genet (Genetta genetta), in addition to free-ranging domestic species such as cats (Felis catus) and dogs (Canis lupus familiaris) coming from small towns and scattered cottages.

Sampling

Camera traps were left at the same point for an average of one month during the first survey, and two weeks during the second, after checking that two weeks was enough to detect the majority of domestic cats moving in the surroundings of the camera. Cameras were separated from each other by a distance between 500 and 1000 m approximately. Between the two surveys, old positions were not taken into account, meaning that some positions might be very close to each other, but correspond to different sampling periods. Two different models of camera traps were used, Bushnell Trophy Cam HD Black Led during the first survey and Acorn LTL5310 during the second, similarly programmed to take 3 pictures per trigger at the minimum speed trigger available. Cameras were tied to trees or deployed using a tripod at 0.20–1 m above ground and set to distances of 2.5–8 m from baits. Camera traps were baited with dried cat food pellets placed in artificial feeding troughs (hand-made PVC pipes of 11-cm diameter and 50-cm long) and tied to trees with ropes in front of the cameras in order to maximise the likelihood of detecting all cats in the area.

Method steps

1. Pictures were sorted following the methodology of R package CamtrapR (Niedballa et al. 2016) in order to extract metadata (date and time of the picture). Consecutive pictures of the same species within a 30 min interval were considered as the same event unless individuals could be identified by their fur patterning (specifically domestic cats and dogs) or other features (injuries, marks, spots). Mammals belonging to domestic animal herds or other species of vertebrates such as birds or reptiles were not included.

1. Canis lupus familiaris
   rank: subspecies
2. Cervus elaphus
   rank: species
3. Dama dama
   rank: species
4. Erinaceus europaeus
   rank: species
5. Felis catus
   rank: species
6. Genetta genetta
   rank: species
7. Herpestes ichneumon
   rank: species
8. Homo sapiens
   rank: species
9. Lepus granatensis
   rank: species
10. Lutra lutra
    rank: species
11. Martes foina
    rank: species
12. Meles meles
    rank: species
13. Mustela nivalis
    rank: species
14. Oryctolagus cuniculus
    rank: species
15. Rattus
    rank: genus
16. Rodentia
    rank: order
17. Sus scrofa
    rank: species
18. Ungulata
    rank: superorder
19. Vulpes vulpes
    rank: species

Camera traps were deployed across Sierra de Aracena and Picos de Aroche Natural Park (province of Huelva; Spain).