The British Herpetological Society

The Herpetological Journal is the Society's prestigious quarterly scientific journal. Articles are listed in Biological Abstracts, Current Awareness in Biological Sciences,Current Contents, Science Citation Index, and Zoological Record.

 ISSN 0268-0130

2021 Impact Factor from Clarivate for the Herpetological Journal is 1.194, an increase of 0.332 from 2020.

pdf 02.Detectability of reptiles in standardised surveys: a test using grass snake Natrix helvetica models


Open Access


pp. 183-189

Authors: Mikaella M.G. Lock & Richard A. Griffiths

Abstract: The ability to detect snakes in the field may be influenced by phenotypic and morphological variables attributable to the target species. These variables include body size, colouration, and body posture. To test what effect these variables had on detectability by surveyors, plasticine model grass snakes were distributed along a predetermined transect in reptile habitat. Detections of different types of snake models along the transect were compared between two groups of inexperienced students and those of a single experienced observer. The experienced surveyor detected 72 % of all the snake models, compared to 53 % and 58 % by the inexperienced groups. All groups detected more larger snakes than smaller snakes, and more uncoiled snakes than coiled snakes. The presence of a yellow/black collar did not influence the detection of the snakes. The results demonstrate the observer bias that may be inherent in surveys of snakes due to variation in size and posture of the target animals. Accounting for such biases in the design of reptile surveys and providing appropriate training and experience for volunteers may improve the validity and interpretation of data collected within citizen science programmes.

Keywords: population assessment, imperfect detection, citizen science, survey protocol


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Please note that as from Volume 31 Number 1 (January 2021) on, the Herpetological Journal will be available as an online publication only - the last print edition will be Volume 30 Number 4.   

Aligning with this change, it is now no longer possible to purchase a subscription that includes a print copy of the HJ.  All members who have existing HJ print subscriptions that remain active as at end June 2020 will receive the full four 2020 print editions.  New subscribers or renewals after this time will only have option to subscribe to the online only subscription package.  Subscription pricing has been amended to reflect the content changes.