Deer in forest counted by wardens
The annual deer census is taking place at Hatfield Forest using a range of primitive and high-tech methods.
The count involves three different techniques; thermal imaging cameras, an ivy trial and studying deer droppings.
Henry Bexley, the head warden at Hatfield, said: "A faecal pellet count is where you take a transect, which is a straight line from north to south.
"We take several of those so we get a good number of different counts done during the census."
The forest is home to around 220 fallow and muntjac deer.
In the autumn it can be hard to spot the pellets amongst the fallen leaves
"The fallow poo this time of year is fairly joined up," said Henry.
"Obviously it's larger than the muntjac faecal pellets.
Also muntjac tend to be habitual they will generally poo in the same area whereas fallow can be a lot more widespread," he added.
Henry is a man who clearly enjoys his job.
"It's fascinating work actually.
"It is one way of getting a fairly good figure of how many deer you have got if you apply it to a mathematical formula which we use," said Henry.
Left unchecked, deer numbers can soar.
The adverse effect of too many deer in a wooded area include damage to the plants and trees.
"We need to be maintaining our deer herd at a responsible level.
"That's an optimum level of around about 150 fallow," he added.