Sir - Roger Moreton is concerned that unfortunate urban foxes can no longer scavenge in our heavy lidded green refuse bins (Letters, March 2).

Others seem concerned that rats will be scavenging in these same bins where refuse may be up to two weeks old. Are rats stronger than foxes, or do they form a team to open the bin lids, whereas foxes scavenge alone? Putting out food for the foxes will be manna for the well-organised rats.

Roger Blackburn, Oxford