Multi‐scale habitat selection of Mus minutoides in the Lowveld of Swaziland

We investigated habitat selection of Mus minutoides in northeastern Swaziland. We used powder tracking to determine how M. minutoides selected habitat at a fine scale and a broader path scale. At the fine scale, we measured per cent cover of grass and shrubs, the number of forbs and visual obstruction (VO) at five evenly spaced points along a mouse's pathway and at a paired random location. At the path scale, we calculated the relative displacement (RD) of each path as the ratio of the distance from the start to the end point of the path to the total length of the path (values near one indicate less preference). We found that M. minutoides were positively associated with increases in visual obstruction, grass cover, and shrub cover at the fine scale, but not at the path scale. Our results indicate that M. minutoides selection of vegetative features at the path scale is not as important as their fine‐scale selection of vegetative structure. In addition, the shrub encroachment on our study site may be directly beneficial to M. minutoides at the fine scale. Our results provide us with an increased understanding of the basic ecology of M. minutoides and information on their response to a changing landscape.     

Vultures acquire information on carcass location from scavenging eagles

Vultures are recognized as the scroungers of the natural world, owing to their ecological role as obligate scavengers. While it is well known that vultures use intraspecific social information as they forage, the possibility of inter-guild social information transfer and the resulting multi-species social dilemmas has not been explored. Here, we use data on arrival times at carcasses to show that such social information transfer occurs, with raptors acting as producers of information and vultures acting as scroungers of information. We develop a game-theoretic model to show that competitive asymmetry, whereby vultures dominate raptors at carcasses, predicts this evolutionary outcome. We support this theoretical prediction using empirical data from competitive interactions at carcasses. Finally, we use an individual-based model to show that these producer–scrounger dynamics lead to vultures being vulnerable to declines in raptor populations. Our results show that social information transfer can lead to important non-trophic interactions among species and highlight important potential links among social evolution, community ecology and conservation biology. With vulture populations suffering global declines, our study underscores the importance of ecosystem-based management for these endangered keystone species.     

Hooded Vultures Necrosyrtes monachus nearly extirpated from Edo State,Nigeria: a report on the avian scavenger community

Avian scavengers, by feeding on carrion and other organic matter, provide critical ecosystem services. Vultures, the only obligate avian scavengers, have reportedly experienced massive population declines in Africa yet current knowledge regarding their status in most West African countries is unknown. This study set out to ascertain the status of the avian scavenger community in Edo State, southern Nigeria. We made total counts of all scavenging birds at foraging and roosting sites in 13 urban areas. We recorded three species of avian scavenger which were, in order of decreasing relative abundance, Pied Crow Corvus albus, Yellow-billed Kite Milvus migrans and Hooded Vulture Necrosyrtes monachus. There was a positive correlation between relative abundance of avian scavengers and human population size, such that more populous urban centres had larger populations of scavengers. We counted more scavenging birds at roosting sites than at foraging sites. While the Pied Crow and Yellow-billed Kite appear to be thriving in Edo State, the Hooded Vulture appears to have experienced a massive population decline. Our results suggest that without immediate conservation effort such as protection, education and advocacy, the Hooded Vulture will be extirpated from this region in the near future. We suggest that these conservation efforts be focused on the largest urban areas. Furthermore, we recommend that other states in southern Nigeria be urgently surveyed in order for more general conclusions to be drawn about the fate of avian scavengers in this region.     

Sexing Cape Vulture Gyps coprotheres based on head morphometrics

The Cape Vulture Gyps coprotheres is considered sexually monomorphic in the literature, but visual differences in head shape between the sexes have been observed. Furthermore, head morphometrics of other Gyps species show statistically significant variation between the sexes. We show that head morphometrics can be used to determine the sex of Cape Vultures. Males generally have wider and shorter heads, and larger bill depths than females. Discriminant function analysis with data from 63 individuals identified the three most predictive variables in sex determination to be head width, head length and bill depth. We also provide an equation that can be used in conjunction with head measurements as a method to determine the sex of Cape Vultures in the field with an overall accuracy of 84% (92% accuracy for females and 72% for males).