On the weekend a fantail and today a swallow; never seen either here before. Both feed on insects on the wing suggesting maybe my insect population is increasing. Currently reading Gaias Garden (Toby Hemenway) on building insect and bird numbers and diversity. He makes a good point that many beneficial insects require flowers as part of their diet, an argument for including more 'non-productive' flowers in the planting scheme. He provides a list of flowers showing which insects they attract. Insects then attract birds, which deposit phosphates. Commercial producers using what they call Integrated Pest Management (IPM) introduce a single species to control a single pest. Often the outcomes are not as predicted. Permaculture basically says the more complex the ecosystem the less the likelihood of any species reaching plague proportions, allowing of course for the cost of additional inputs to be set against the law of diminishing returns.