The presence of old nest structures can be an influential resource in reuse patterns and reproductive output for some birds. We used 15‐year territorial occupancy data referring to the booted eagle Aquila pennata (a trans‐Saharan migrant) and the common buzzard Buteo buteo (a sedentary species in southeastern Spain) to analyse old nest effects in territorial settlement patterns (new territories, new establishments in old territories and reoccupancies), to describe the patterns of nest building versus nest reuse and to test whether nest building is costly in terms of current reproductive output. The results indicated that the rates of reoccupancy and new establishments in old territories were higher than the rates of creating new territories for both booted eagles (74.13, 23.35 and 2.52%, respectively) and common buzzards (58.25, 38.84 and 2.91%, respectively). When breeding pairs settled in old territories, we observed a noticeably lower pattern of nest building than nest reuse both in booted eagles (10.03 vs. 89.97%) and common buzzards (8.00 vs. 92.00%). The nest‐building rate by booted eagles was significantly lower in reoccupancies than in new establishments in old territories. Reproductive output for each species was not increased by nest reuse, although breeding success and productivity were significantly higher when newly established booted eagles constructed new nests than when reusing old nests. Our findings provides an interesting view on how forest raptors use old nests as important resources, probably taking them as location cues for nesting site selection and suggesting that unused nest sites should be left undisturbed since they could attract breeding raptor pairs in future years.

Interactions between top predators and mesopredators of the same guild often result in habitat segregation restricting interactions to shared habitat edges. Although negative edge effects are recognized as important spatial patterns in the ecology of fragmented landscapes, the underlying mechanisms of predator–prey interactions resulting in negative edge effects remain unknown. To disentangle top‐down effects of intraguild predators and bottom‐up effects of shared resources on mesopredator spatial distribution, we recorded the occurrence of tawny owls Strix aluco in forests and their prey, the little owl Athene noctua in adjacent open areas over 2 yr across 687 km² in Southern Germany. We developed a new, asymmetrical dynamic two‐species occupancy model investigating spatial interactions while accounting for imperfect detection. Little owl occupancy was strongly reduced within 150 m of forests, but only in the presence of tawny owls. Analysis of over 30 000 telemetry locations of 275 little owls showed that little owls strongly avoided areas closer than 150 m from the forest during range use. These results suggest that the negative edge effect is due to forest edge avoidance rather than direct predation. Potential confounding mechanisms such as food depletion or habitat avoidance at forest edges can be ruled out. Thus, top‐down effects caused by avoidance of intraguild top predators shape the spatial distribution of mesopredators such as the little owl. While habitat complexity mitigates multitrophic interactions within habitats, it is expected to reinforce multitrophic interactions between habitats, potentially leading to the suppression of mesopredators from suitable habitats.

Occurrence models that account for imperfect detection of species are increasingly used for estimating geographical range, for determining species-landscape relations and to prioritize conservation actions worldwide. In 2010, we conducted a large-scale survey in Río Muni, the mainland territory of Equatorial Guinea, which aimed to estimate the probabilities of occurrence and detection of threatened mammals based on environmental covariates, and to identify priority areas for conservation. Interviews with hunters were designed to record presence/absence data of seven species (golden cat, leopard, forest elephant, forest buffalo, western gorilla, chimpanzee and mandrill) in 225 sites throughout the region. We fitted single season occupancy models and recently developed models which also include false positive errors (i.e. species detected in places where it actually does not occur), which should provide more accurate estimates for most species, which are susceptible to mis-identification. Golden cat and leopard had the lowest occurrence rates in the region, whereas primates had the highest rates. All species, except gorilla, were affected negatively by human settlements. The southern half of Río Muni showed the highest occurrence of the species studied, and conservation strategies for ensuring the persistence of threatened mammals should be focused on this area.