An improved identification marking method for hedgehogs.

As part of a long-term study of hedgehogs in The Regent’s Park (London, U.K.) begun in May 2014, we developed and tested an improved identification marking method using 10 mm lengths of yellow plastic sleeving (heatshrink polyolefin) bearing pre-printed animal identification numbers. During twice-yearly study periods, six spines on each hedgehog were marked with duplicate numbers in a single central patch just behind the crown of the head; easily visible in both active and rolled-up hedgehogs. From May 2016 (animals marked in September 2015) to May 2018, the mean number of tags remaining in the pelage after eight months (September to May) was 3.78 (SE = 0.24, n = 45) and 4.16 (SE = 0.31, n = 25) after four months (May to September). In five additional cases, individuals were easily identified after periods of one year or more. The tags have minimal welfare implications, do not interfere with the function of the spines and can be easily read by anyone finding the animal. We conclude that this method is very effective, requires minimal handling and is suitable for use by volunteer field workers. Only one marked spine allows correct identification, making it especially suitable for identifying road-killed, partially eaten or decomposed hedgehogs.