Here is an idea developed by Chris Beardshaw, that I spotted at Hampton Court Flower Show in 2008. The idea has been widely proliferated at flower shows since then and I have since seen many different takes on the idea. This, however, is an ingenuous mixture of nooks and crannies that will provide safe habitat for a variety wildlife: Hedgehogs, solitary bees, over-wintering ladybirds, reptiles and amphibians such as frogs and toads and most of the materials can be acquired from recycled and 'found' sources. Adding beneficial insects to your garden is one of the best things you can do as they will eat all of your pests and make sure you have healthy, organic fruit and vegetables. I have never any problems with pests in my permaculture garden since I set it up in 1991 due to the rich variety of insect attracting plants and wildlife habitats that have been deliberately created since day one. Added to that, as honey bee populations sadly decline, it is even more important tthat we attract solitary bees into the garden as polinators and provide homes for them.