Issue 4.3 is now available to read online, spanning parasitology, diversity and distributions, behavioral ecology, heredity and theoretical population biology. It also includes the freely available application article “Sample Planning Optimization Tool for conservation and population Genetics (SPOTG): a software for choosing the appropriate number of markers and samples”.
About the cover: Long-term demographic studies that use individually identified animals offer invaluable views of ecological processes. Photo-id is a powerful tool for studying wild animals, particularly as there is no need to handle the animals – a good image is all that is required to “capture” individuals for life. ExtractCompare is the latest version of a freely available semi-automated photo-id system that allows standardized comparison of natural patterns. Crucially, the new software takes into account some of the complications that arise with data of this type which had been overlooked previously. Although female grey seals (Halichoerus grypus) are distinctively and laterally asymmetrically patterned, they pose a challenging problem for automated photo-id because of the impossibility of controlling the camera distance and angle to the subject (seals swimming offshore, and only partly visible as pictured, or lying on the shore) and the wide range of body postures they display. This work uses an extensive photo-id database of an intensively studied breeding colony, North Rona, to consider the problems of individuals generating multiple encounter histories through the risk of false rejection of matches or being captured from a single side. Survival, abundance and preference can be estimated now using patterns from different body areas by measuring and allowing for the risk of false rejection. In “Analysis of photo-id data allowing for missed matches and individuals identified from opposite sides“, the research confirms that apparent annual survival of female seals at North Rona is lower than expected, something that is reflected in the declining number of seal pups born there. Pup production at the island has fallen from over 2000 in the 1970s to around 500 at present, whereas other colonies have increased.
Image by Patrick Pomeroy.
To keep up to date with Methods newest content, have a look at our Early View articles which will be included in forthcoming issues, and our list of Accepted Articles, which will be available online soon.