A practical approach with drones,smartphones,and tracking tags for potential real-time animal tracking

Drones are increasingly used for fauna monitoring and wildlife tracking;however,their application for wildlife tracking is restricted by developing such systems.Here we explore the potential of drones for wildlife tracking using an off-the-shelf system that is easy to use by non-specialists consisting of a multirotor drone,smartphones,and commercial tracking devices via Bluetooth and Ultra-Wide Band(UWB).We present the system configuration,explore the operational parameters that can affect detection capabilities,and test the effectiveness of the system for locating targets by simulating target animals in savanna and forest environments.The self-contained tracking system was built without hardware or software customization.In 40 tracking flights carried out in the Brazilian Cerrado,we obtained a detection rate of 90%in savanna and 40%in forest areas.Tests for targets in movement(N=20),the detection rates were 90%in the savanna and 30%in the forest areas.The spatial accuracy obtained by the system was 14.61 m,being significantly more accurate in savanna(x=10.53)than in forest areas(x=13.06).This approach to wildlife tracking facilitates the use of drones by non-specialists at an affordable cost for conservation projects with limited resources.The reduced size of the tags,the long battery life,and the iower cost compared to GPS-tags open up a range of opportunities for animal tracking.

Challenges in estimating ancestral state reconstructions:the evolution of migration in Sylvia warblers as a study case

Our current understanding of how species have evolved is mainly based on comparative phylogenetic methods,which use phylogenies to infer the evolution of traits.The development of ancestral state reconstruction(ASR)methods has provided the tools to reconstruct trait evolution,which are widely used in fields like evolutionary biology,macroecology and paleontology.As there are different elements involved in those analyses,with different levels of uncertainty(i.e.relating to branch length estimation,trait coding,statistical framework,taxon sampling or software),the various combinations of these elements likely have a strong impact on the reconstruction of the evolution of traits,potentially leading to opposite conclusions.To assess the impact of these different elements in ASR,we performed a set of analyses,including all possible combinations of such elements and using the evolution of migratory behavior in Sylvia warblers as a case study,which was coded as a continuous or as a discrete character.Our results show that taxon sampling,character coding,tree shape,statistical framework and software all significantly affect ASR,both individually and in combination.Not all reconstructed tree nodes show discrepancies,but in the critical ones most pairwise comparisons between analyses lead to conflicting and unexpectedly antagonistic results(zero migration vs fully migratory),thus challenging interpretations of trait evolution.We propose some possible solutions to partly inform decisions,involving the method selection and the incorporation of biological or fossil evidence regarding how traits evolve,but our results demand serious rethinking about how the research community currently uses ASR.

Measuring disturbance at swift breeding colonies due to the visual aspects of a drone:a quasi-experiment study

There is a growing body of research indicating that drones can disturb animals.However,it is usu-ally unclear whether the disturbance is due to visual or auditory cues.Here,we examined the effect of drone flights on the behavior of great dusky swifts Cypseloides senex and white collared swifts Streptoprocne zonaris in 2 breeding sites where drone noise was obscured by environmental noise from waterfalls and any disturbance must be largely visual.We performed 12 experimental flights with a multirotor drone at different vertical,horizontal,and diagonal distances from the colonies.From all flights,17%caused<1%of birds to temporarily a bandon the breeding site,50%caused half to abandon,and 33%caused more than half to abandon.We found that the diagonal distance explained 98.9%of the variability of the disturbance percentage and while at distances>50 m the disturbance percentage does not exceed 20%,at<40 m the disturbance percentage increase to>60%.We recommend that flights with a multirotor drone during the breeding period should be con-ducted at a distance of>50 m and that recreational flights should be discouraged or conducted at larger distances(e.g.100 m)in nesting birds areas such as waterfalls,canyons,and caves.