What do great crested newts and zebras have in common?

By Laura Osborne

We have been surveying the newts in our Cambourne office pond for the last six years, using a unique method...

Many animals have unique features that enable us to identify individuals. We have fingerprints, zebras have stripes and great crested newts have patterned bellies. This has enabled us to undertake a study into the newts that live in our garden at Cambourne.

We are fortunate that great crested newts are widespread in Cambridgeshire and in places have large healthy populations. However, this is not the case across the whole of the species’ range where intensification of agriculture in the late 20th century caused a loss of suitable breeding ponds and surrounding natural habitat. Consequently, populations have been lost or greatly fragmented and the species and its habitats are legally protected to ensure their future survival.

Our study focusses on the great crested newts that use our garden pond in Cambourne. The pond was created 14 years ago and today is thriving with wildlife – including a seemingly large population of newts. But how many newts can the pond support and how stable is the population? In 2013, I started a programme of capturing the newts and photographing their belly patterns in order to build up a catalogue of individuals. The newts are caught in funnel traps made from plastic bottles, a standard technique and licensed by Natural England. They are then held gently between a sponge and clear plastic whilst a photo is taken and then returned to the pond.

Patricia the great crested newt and her belly pattern, held against a clear plastic tub lid by a sponge

Patricia the great crested newt. They are photographed whilst being held gently between a sponge and clear plastic, and handled by licensed newt handlers.
Photo by Laura Osborne.

The surveys are carried out in the Spring as this is the newts’ breeding season and when most individuals are active in the pond. Once newts have bred, they spend most of their time in nearby terrestrial habitats such as log piles, compost heaps, rough grass and woodland. Over the six spring periods, 75 male and 52 female great crested newts have been identified. This sounds like a lot of newts considering the size of the pond, however only 33 have ever been recaptured and some ‘disappear’ for a few years before being caught again.

Our garden is well connected to nearby Oaks Wood and adjacent gardens, which make up a strong habitat mosaic for the newts to utilise. In order to understand how our pond fits into the local landscape and the character of the newt metapopulation, the study now includes two ponds in Oaks Wood. So far, 80 newts have been identified from these ponds but there is no evidence to support the idea that the animals are moving between garden and woodland ponds despite them only being 200m apart. It is thought that great crested newts can live for approximately 15 years in the wild, therefore it will take many more years of surveying to better understand our local population. 

Great crested newt belly patterns over time

Analysing the photos of belly patterns has taught us a bit more about how patterns change over time. These photos show Jenny and Linda who were both caught in 2014 and again in 2018. Jenny is a younger newt so has sparser spots initially and then develops more over time. Linda is an older newt with a more developed pattern so hers changes very little over the same time period.