Mammals along Grantham Canal

I had the opportunity to borrow a trailcam last year and I took the opportunity to see what wildlife could be recorded along the banks of Grantham Canal. The trailcam triggers when it detects movement and can record at night so placing it along animal trails allowed me to see what creatures used them.

Below are a few clips of some of the animals I recorded. These show how important the Grantham Canal is to a wide range of wildlife, not just in terms of the aquatic habitats it provides but the hedgerows, trees and shrubs which run alongside it – ten different mammal species were recorded over a few weeks of deployment and this is alongside at least five species of bat which I recorded last September – you can read more about the bats along Grantham Canal here.

Muntjac Deer

I recorded muntjac deer on a number of occasions. These are small deer, around the same size as a medium-sized dog. They are not a native species – they are originally from China but were introduced to the UK in Bedfordshire and have since spread to be present throughout the British Isles. Other deer such as roe deer are also present in the wider landscape around Grantham Canal but I did not record any on the trailcam.

Foxes

Foxes make use of the habitats along the Grantham Canal with the trailcam recording both adult and juveniles. The traditional agricultural view of foxes is that they are vermin, but they are a native species of mammal in the UK, fulfilling quite an unique niche now that we have exterminated the wolves, lynx, wildcats and other larger predators which historically existed in the UK. In the first clip of the recordings, you can see a younger fox mark its territory as it walks past.

Badgers

Badgers move out from their main setts each night and find food within the wider countryside. Foraging areas change throughout the year depending on the use of the land and the conditions. Sheltered linear features such as the canal banks provide an important connective route to allow them to reach these foraging areas. The habitats within the canal corridor are also likely to provide important foraging areas in their own right.

Hares

Hares differ from rabbits in that they do not use burrows – rather they rest in ‘forms’ which are low depressions in the land, often under the cover of long grasses or other vegetation. They forage and spend much of their active times in the arable fields which bound the canal through much of its course, but the trees and shrubs within the canal corridor provide an important place of rest and shelter during the daytime.

Rabbits

Rabbits shelter in burrows and many of these burrows can be found along the banks of the Grantham Canal. The slope of the banks mean that they can tunnel sideways rather than down to create their warrens, which requires less energy and is therefore more efficient. They graze upon low growing vegetation within the Canal Corridor but also use the wider arable fields which bound much of the canal.

Stoat

I only recorded one instance of a stoat along the Grantham Canal. These are small predators, larger than a weasel but smaller than a ferret or a polecat. As you can see from the clip, they are very agile and feed on other small mammals such as rats and rabbits which are plentiful along the canal route.

Grey Squirrel

The grey squirrel is another invasive species which will be familiar to everybody, whether you live in the city or the countryside. In the autumn, the squirrels kept very busy gathering nuts and storing them away underground to be unearthed through the winter and spring when food was scarce. The horse chestnut, hazel and beech trees along the Canal would provide a good source of nuts to store away, whilst the glut of berries from the hawthorn, blackthorn and rose bushes would keep them in good health whilst they work.

Mink

The American Mink is another species which is not native and yet has found itself a home along the Grantham Canal, along with many other rivers and watercourses across the UK. I was very surprised to catch this one descending a tree just in front of the trailcam – not usual behaviour but something which they are known to do, especially when escaping a predator or perhaps when seeking food such as birds nests. The second piece of footage, showing the mink skulking away with its high arched back is more characteristic.

Other species recorded by the trailcam include rats, mice, herons and a variety of other small birds such as blue tits, great tits, chaffinches and blackbirds. Pheasants too often stroll along the banks and scratch for food morsels within the soil.

Mink climbing a tree

I wanted to share a rather unusual video clip which I captured on a trailcam recently. I know mink to be good swimmers but I did not realise they were tree climbers! Various sources suggest this is a known behaviour, with some suggesting they climb regularly whilst others suggest rarely. One website states that they frequently climb to escape predation although there is nothing to suggest that this was the case in this video.

One of the best applications of a camera trap is when it allows you to observe something unusual or unexpected which could not otherwise be obtained without hours of watching and waiting. I think this clip is a perfect example!

Red-eared Terrapin in Grantham Canal

I had something of a surprise when out walking along the Grantham Canal at the weekend. A friend posted a cracking photograph of a mink on twitter (and now on her blog which you can read here) which was seen along the stretch between Harlaxton and Denton. This is a non-native species and can cause serious damage to the ecosystem through their predation on native species of fish, birds and water vole. However, it is argued that, as these are all food sources for the native otter, the non-native mink is filling a currently vacant ecological niche for a semi-aquatic carnivorous mammal in our waterways. Whilst the grey squirrel competed with the native red in a similar way to the detriment of the reds, there is good evidence to suggest that the re-colonisation of a watercourse by otters will lead to the displacement of the smaller mink and so the native species would win out in the end. Whilst we wait, and hope, for otter to continue their spread through our native watercourses, the mink could be seen as its understudy. They can however cause serious problems in some locations, especially where they prey upon the eggs of sensitive bird species, and eradication programmes are in place in a number of locations to remove them. I have only once seen a mink along the canal, on the stretch by Woolesthorpe some years ago, and was keen to see another.

I was scanning the edge of the canal as we walked along and was taken aback to see a completely different non-native species instead – a red-eared terrapin (Trechemys scripta elegans) basking out of the water on a log! This individual was around 30-40cm which is adult sized. These reptiles, originally from the Americas, were popular pets in the 1980’s and 1990’s following the Teenage Mutant Ninja Turtles on childrens’ TV. They tended to out-grow their confinements and many of the more irresponsible owners simply released them into the wild. They can live for several decades and so this specimen could have been in the canal for a long period of time. The sale of these species does continue however so it could be a more recent arrival.

Red eared terrpin in British canal - Grantham Canal, Lincolnshire, UK

The terrapins feed on aquatic invertebrates and amphibians and so, like the mink, are a cause for concern in British waterways. Whilst the mink is quite able to breed and spread throughout the UK, there is less concern about the terrapins at present – they require around 100 days of >27 degrees or 60 days of >30 degrees for the eggs to successfully hatch and the young to develop which is rarely achieved in a British summer. This puts the terrapin into a different category to the mink – whilst they are not desirable, they are at least naturally controlled by the climate and they should not increase under their own steam. This means that there is not currently a requirement to control them in the wild; rather better controls on the sale of these species should ensure that they do not continue to be a problem once the individuals at large have died out naturally. That said, increased temperatures as a result of climate change could see this whole situation change! A juvenile was spotted Regent’s Canal in London last year and this caused concern that they might have found conditions warm enough to breed in our unusually hot summer.

The individual spotted in Grantham canal may even be the only one present – if no others were released alongside it. There is a record of an European Pond Turtle in the canal from 2006 which may be a misidentification of the same individual I saw, or it could be that this non-native species is also present along the waterway.

Next time you are walking along the canal, keep an eye and you might just spot something unexpected!