From the smallest stick insect to the tallest giraffe – every single animal in Dudley Zoo’s collection has been counted as part of the venue’s annual “stock take”.

Workers at the attraction, in Castle Hill, carry out the census every year to record the total number of animals at the site as part of its licence.

There are 1,500 animals and 177 different species housed at the zoo and keepers, armed only with clipboards and pens, have to catalogue them all.

It involves a head count of each animal which is then written down on a form. But while staff looking after the larger animals have no trouble, it is the smaller species that give staff the biggest headaches – by doing everything they can to avoid the count.

Zoo chief executive Peter Suddock said: “The keepers looking after the larger animals do tend to have it easy. For example we know the zoo has four Bornean orang-utans and three Asiatic lions. However the stick insects are particularly difficult to count as they jump around all over the place. The penguins also try to avoid the count by moving around the enclosure.”

Keepers said despite the difficulty cataloguing them, staff were eventually able to get a total number of Humboldt penguins based at the zoo – 59, the largest number of birds at the site.

Curator Matt Lewis said: “The count is very important and something we prepare for. We generally set aside a day so the count can take place and the results can be compiled.”