For most businesses nothing is more tedious than a stock-take – but when your stock flies, runs, waddles and swims the task becomes a great deal more complicated.

That is the challenge being faced by wardens at the popular Pensthorpe Nature Reserve, near Fakenham, who have been carrying out an annual stock-take of the reserve's inhabitants this week.

To maintain its zoo licence the reserve has to record the captive animals being kept on site and report them to North Norfolk District Council.

Four wardens carry out the job, armed with clipboards and binoculars they cover approximately 60 acres of the 500-acre reserve. It usually takes between three and four days to complete the count.

And as reserve and conservation manager Tony Durkin explained, it is a job that requires a great deal of patience.

He said: 'Sometimes it can take an hour or two trying to find one elusive bird that is hiding away in some reeds. These are wild animals and they don't stop and wait to be counted.

'This is one of the most difficult jobs that I have to do, but is also a very interesting and exciting one which I believe all of the wardens enjoy and look forward to doing.

'It gives us the chance to get out there and see all of the birds we have been breeding and to check that they are all healthy and in good condition.

'It is also great training for some of the younger wardens who may need to get up to scratch with species identification.'

Everything from the reserve's exotic greater flamingos and Manchurian cranes, which are the biggest birds on the reserve at more than 6ft tall, to the smaller birds such as waders and bearded reedlings, kept in aviaries, have to be counted. These smaller birds are captured before they are counted.

Last year's stock-take counted 77 species made up of 75 different bird species and two mammal species, harvest mouse and red squirrel, and a total of 670 individual specimens.

This year's figures are still being gathered.

Mr Durkin said: 'We keep regular records of when animals are born and die and move on and we have to do this annual stocktake to make sure our records tally up.

'Pensthorpe has been required to do this since it got its zoo licence more than 10 years ago and any place like this would be in total chaos if we did not count the species here at least once a year.'

Records of captive animals are maintained by the government on a national database.

They are referred to by DEFRA, which can be involved in tracing animal movements.

The figures also make the government aware of any significant increase or decrease in any particular captive species in the country.

See a picture gallery of the stock-take at www.edp24.co.uk.

adam.lazzari@archant.co.uk