We only net our fields during the fruiting season.  We have chosen a mesh size that allows small birds such as tits and sparrows through but keeps out the larger birds that would dearly love to feast on our blueberries such as blackbirds and pigeons.  During our second summer we could not afford bird netting and we lost nearly 80% to birds, there were some very fat birds in Bettisfield that summer.  

As a consequence of using netting the fields become an absolute haven for insects, I have never seen such huge dragon flies - I joke not when I say they are as big as my hand!  The insects under the nets become a very attractive “fly thru” snack for all the smaller birds that can get through the netting.  When the fruit has been harvested we withdraw the nets, tie them up and the fields remain open for the remaining nine months of the year.