Guano Island

This 500m long island can be counted amongst New Zealand's unfairly named places. Just off Bream Head and grouped with Mauitaha and Moturaka and Tarakanahi Islands, Guano is reported to a wonderful picnic spot and waka-ama course. Which begs the question as to why it is named specifically for seabird excrement. There is likely to be some, but a parallel with the Chincha Islands where the Peruvian booby bird is so prolific at producing guano that they build their nests from it, and still more is left over that is mined and converted to fertiliser, might seem a bit on the nose.
Have you been to the New Zealand Guano Island, are you going there, could you supply NZPlaces a picture? As explorers of the cultural landscape, we want to know, why Guano?