Friday, 22 May 2015
Water Vole Surveying Along a Canal, Release of another Emperor Moth and a late Blue Tit nest
Seven or eight years ago I undertook water vole surveys for the local Wildlife Trust after attending one of their Water Vole Surveying Courses. Unfortunately, I eventually had to give them up due to lack of time with the number of family commitments I had then. Of all the surveys I've done in the past Water Vole surveying was the one I enjoyed the most so when I noticed the People's Trust for Endangered Species had launched a National Water Vole Monitoring Programme I decided to register to take part. Water Voles are our fastest declining mammal. A National Water Vole Survey in 1989/90 estimated a 94% loss of water vole sites during the 20th century. The most recent national survey which took place in 1996/98 revealed a further loss of 89%. The aim of the PTES monitoring programme is to make yearly visits to sites that were surveyed in the 1980's and 1990's to gather up to date information on the distribution and abundance of the species and to detect any changes since the last survey and to monitor future changes.
Water voles (Arvicola amphibius) are mainly found along slow flowing rivers, streams, canals, lakes and ponds. They are vegetarian and have been recorded eating 227 plant species, mainly bankside grasses and sedges, marginal and emergent plants and in winter they will eat berries, tree bark and roots. They live in colonies along banks where they dig a burrow system into the bank although on rough pasture land they will build woven nests. Water Voles receive full legal protection and, due to their dramatic decline, have been designated a Priority Species under the UK Biodiversity Action Plan (BAP).
Reasons for their decline include:
Loss and degradation of habitat due to river engineering, canalisation, bank reinforcement, lack of riparian management or inappropriate bank management.
Fragmentation of habitat which isolates colonies.
Predation by the non-native mink (Mustela vision) which escaped or was released from commercial mink farms. Female mink, in particular, are very effective predators and can hunt water voles on land, in the water and are small enough to pursue voles into their burrows. A breeding female mink can wipe out a whole water vole colony.
Disturbance of colonies due to activities along the river and on the water course.
Poor Water Quality and pollution (from farm waste, insecticides and herbicides)
Poisoning due to mistaken identity and the inappropriate use of rodenticides.
The PTES survey involves visiting the allocated site(s) in May to walk a 500/600 metre continuous route noting on the way any field signs of water voles, for example, actual sightings, burrows, latrines, feeding signs and grazed lawns. Locations of these in each 100 metre stretch need to be recorded. Field signs (scats/spraints and tracks)of otters and mink, if found, are also noted.
Water voles are rare in Warwickshire. There are colonies in Coventry, Wolvey and Nuneaton and a few isolated colonies elsewhere. Unfortunately, I have had problems gaining landowner permission for the brook I hoped to survey in Warwickshire. In fact, in the end he refused although failed to give any reasons which was disappointing to put it mildly. There were no such problems with the other site I planned to survey - a canal in the West Midlands which I surveyed earlier this week.
When you are surveying for water voles you really don't want to see bank reinforcements such as these
as it means water voles are very unlikely to be present as they cannot burrow into the bank. There were around 300 metres on the opposite bank of the canal which appeared to be reinforcement free
but the whole of the bank on the side I was walking had brick reinforcements so it wasn't really surprising that I found no water vole field signs at all. I will go back in September though just to double check and I may walk further along the canal to see how far the reinforcements go.
Once I'd done the survey I was free to take note of the flora and fauna along the canal.
B had just spotted a Reed Bunting.
Sorry the photos aren't very good - I took the Bridge Camera which I still haven't mastered. It was a bit foolhardy really but I just stuck it on automatic and used it as a point and shoot. Not easy taking photos of moving objects with one hand as I was also holding, maps and survey forms in the other.
Mallard and ducklings
This Grey Heron was a very long way away taken on full zoom.
Moorhen and Young - sorry really dreadful picture but it was so cute.
It was pleasing to see the number of nestboxes on the farmland opposite
An interesting looking footpath into a nature reserve adjacent to the canal.
Sad sight - fly tipping in the car park :( Can never ever understand why people drive to places like this or deep into the countryside to get rid of stuff when they could just as easily visit their local rubbish collection point.
When I made a preliminary visit to the canal a week or so ago I took these photos of dandelions with the Olympus. It really does seem to have been a good year for dandelions.
Emperor Moth News
So far 3 males have emerged from the cocoons - all now safely released.
Sadly, no females yet.... so I haven't had chance to try assembling.
It can take several years for the moths to emerge so in a few weeks I'll put the cocoons back in a cool place and wait until next year.
I've been offered some more emperor eggs/caterpillars and I may take up the kind offer - though will ask for fewer this year!!
Moth trapping in the garden this May so far has been exceedingly depressing with hardly any moths trapped. As its Garden Moth Scheme night I will try again tonight.
Blue Tit Nesting News
Despite activity from a pair of blue tits constantly visiting the nestbox over several months there were no signs of nest building and I really had given up hope. Last week there was another sudden flurry of activity and the female built a nest within a couple of days and she is now incubating six eggs. This nesting attempt is very late compared to usual!