Autumn and winter populations of wild game birds are determined by the productivity of breeding adults during the previous spring. The number of chicks recruited to the population that make it to maturity is determined by weather conditions just after the hatch, predation at the nest and chick survival.
Mortality among game birds is at its highest during their first two weeks. During this period, chick survival can be extremely poor in areas when insect abundance is low.
To feather up and grow quickly chicks require for their first 10-14 days, (depending on species) a diet of almost pure protein. As they can only generate a small percentage of their own body heat, they require constant brooding by the parent birds hence the reason chicks can only forage for relatively short periods. During these foraging periods, they need to consume large quantities of protein rich insects.
Game bird chicks do not eat insects indiscriminately but prefer certain groups. Research undertaken by scientists working on the Irish Grey Partridge Conservation Project has shown that insect abundance is far greater in areas when crops are planted specifically for game.
Crops planted for game are not sprayed with herbicides or insecticides and are sown below the recommended seeding rates, in other words an acre pack of seeds will be sown over an acre and a half. A reduction in the sowing rate keeps the chicks drier and facilitates easier movement through the crop while they search for insect food.