Are nesting sites the only problem?

Insects in towns and cities should not be affected by chemicals like they are in farmland, so are Swifts using these habitats to feed? These comments were taken from a recent bird blog – “nice feeding flock of at least 50 birds low down over rape seed crop” and “still at least 70 Swifts feeding over rape field”. Could this mean chemicals in farmland insects may be a problem? In Andrew’s chapter (included in the reprint of his father’s book), he mentions that oilseed rape fields seemed to offer more potential than cereal fields, as the Brassica Flea Beetle was turning up in the droppings analysed at the tower. This is when oilseed rape is one of the most heavily sprayed crops, to destroy insects, out of all the crops in the UK. One Sussex farmer told Professor David Goulson that he sprayed his oilseed rape 22 times in one year! On the chemicals, Chris Jarvis, Oxford University Museum of Natural History, said: “I have been told that there are faecal samples that were collected several years ago, which would give us a good insight into the chemical composition of their food and could be usefully analysed to show whether there may have been any effects caused by insecticides or other man-made chemicals in their food. “It would also be interesting to look at the chemical composition of their discarded egg shells. I am unaware of any departments where this has been suggested as a possible Phd/research project, although I have asked several people about it. Although the problem with food sources may not necessarily be linked to agri-chemicals, but purely down to the massive decline in insects, with some recent European studies suggesting and overall drop in insect biomass of up to 70% in the last 50 years.” This prompted me to speak to the ‘insect man’ from the Pest Evaluation Service of DEFRA. Steve Ellis said: Psylliodes chrysocephala is what we call Cabbage Stem Flea Beetle (CSFB). It has become an increasingly important pest in recent years in oilseed rape, particularly in the east of England. The life cycle of the beast is such that it will be present as a larva in oilseed rape crops (and other brassicas) up until about the end of April, after which it pupates in the soil. “The adults emerge in June/july and feed on the foliage of the crop before going through a resting phase in sheltered areas, possibly hedgerows usually after the rape harvest in July/august. Therefore, I’m a bit surprised that Swifts have the opportunity to feed on these beasts, as they probably spend most of their time in or close to the crop. I don’t know much about Swifts but I get the impression that they feed at a higher altitude than the likes of swallows and martins, where I would have thought there would be fewer CSFBS’. All in all, a Swift City Project may just be a ‘tip of the iceberg’ in saving the Swift here and in Europe. More work is certainly needed on food and the effects of chemicals on the birds as “Insect-eating birds are seeing the fastest decline in any birds in Europe”.