ON the east side of Doncaster, the land is as flat as the eye can see. Fields of crop, many of them dazzling sheets of yellow rape in springtime, are broken only by the odd clump of trees or overgrown hedgerow. It is far from the classic wild deer territory
of rugged mountains and dark forests.

But deer are numerous here, and largely unthreatened by powerful hunting rifles. They are mostly small Roe Deer, looking so cute in their reddish-brown summer coats, and being territorial by nature they have for many years established breeding and rutting grounds on the two main areas of surviving peatlands which lie mostly hidden by fields – Thorne Moors to the north, and Hatfield Moors to the south.

Few predators make much impact on their population, but recently they have been dying in ever-growing numbers, particularly throughout the months of May and June.

For some reason – and no one knows precisely why – significant numbers of them move south from the direction of Thorne Moors and drown in the Stainforth and Keadby Canal, one of Yorkshire's least-known and least visited waterways.

The canal runs east for 15 miles from the traditional coalmining area around Stainforth, near Doncaster, to the tidal River Trent at Keadby. But on one particular stretch of about one-and-a-half miles in length, between Moors Bridge and Mauds Bridge near Thorne some 30 and 40 deer are known to die annually.

This year, however, the mortality figure should be much lower, thanks to work by an unusual alliance of organisations. Tons of limestone have been dumped into the edges of the 8ft-deep canal to create "deer ramps" which will allow the animals to scramble out of the water rather than remain trapped by the sheet metal piles of the canal walls until they no longer have the energy to keep themselves afloat.

The problem first came to light a decade ago when a man who lived beside the canal was reported to be regularly jumping into the water to rescue deer.

"For us, it actually began as a Health and Safety issue regarding humans rather than wild animals," says Jonny Hart-Woods, the heritage and environment manager for British Waterways Yorkshire. "The gentleman in question told us he was having to rescue more and more deer every year. That was the first time we realised there was a serious issue."

It had been known for some years that Roe Deer were drowning on another canal, the Aire and Calder Navigation, particularly the 20-mile stretch from Knottingley and the River Ouse, largely because their decomposed carcasses were eventually winding up floating in Goole Docks and their safe disposal was costing Associated British Ports a lot
of money.

But most of the corpses of the Stainforth and Keadby Canal deer were simply not being found. It was only when individuals required rescuing – sometimes with the help of South Yorkshire Fire Brigade – that the scale of the problem was realised.

The RSPCA became involved at an early stage, contacting British Waterways with a suggestion that they might wish to investigate providing some kind of structure which would allow deer to climb out of the water. But nothing came of the proposal – it probably stalled during British Waterways' internal restructuring of the late 1990s.

Fast-forward to 2005, and the deer drownings seemed to be more frequent than ever. So much so that local naturalist Colin Howes, who collects environmental records for the Museums Department of Doncaster Council, had written an academic paper on the subject.

The first record of a drowning he traced was for 1977, and since then the figures had continued to rise.

"What I found was that early to mid-summer was the peak for this happening," Colin says.

"It's an absolute puzzle as to why they are coming to cross the canal during this particular period. My own interpretation is that it's something to do with the harvesting times.

"When crops are taken out the deer have got nowhere to hide, and nowhere to feed, so they move on and many of them come in this direction.

"Also, May and June is the time when bucks become more territorial, and the does are aggressive with their previous year's young."

So it could be that it is low status males and unwanted young deer that are being flushed out and forced to try and swim over the canal, probably a territorial boundary.

When he was brought into the picture, Jonny Hart-Woods of British Waterways quickly identified that one remedy might be to prevent deer
from crossing the Doncaster to Cleethorpes railway line, which runs adjacent to the canal at the drownings hot-spot.

Realising that the solution, long-term, required the bringing of several different groups together, he took the problem to a surgery held by the newly elected MP for Doncaster North, Ed Miliband.

Mr Miliband agreed to chair a working group, which has now led to the provision of a two-metre-high deer fence costing £50,000, built by Network Rail, and the creation of four deer ramps in the canal. A further two are planned.

"Of course it was a very unusual issue to be raised with me," Mr Miliband said last week as he visited the canal to see the work.

"I remember going off from my surgery to look at the Stainforth and Keadby and thinking I'd gone a bit mad. But, seriously, it's been a fantastic team effort, and really shows what can be achieved if you sit down and try to solve a problem."

The work has already proved a success. Deer which have somehow still managed to get through to the canal bank and jumped into the water have been observed climbing out on
the ramps.