The RSPCA has warned against the dangers of scaring geese away using lasers after King's College adopted the unusual method.
Porters at King's College started using hand held laser guns to scare geese away from its formal lawns last March, but has denied it is inhumane.
The deterrent was adopted after a persistent gaggle of Canada geese started fouling on the lawns and dive bombing tourists queuing to hear evensong.
Responding to concerns over the geese's welfare, the RSPCA say lasers should not be shone into animals' eyes and the technique is yet to be proven humane or effective by researchers.
However, the animal welfare charity refrained from being critical of the college and would keep an open mind should it be proven safe.
A spokeswoman for the RSPCA said: "As with humans, we would not support shining a laser directly into an animal’s eye.
“However, we are aware that the indirect use of lasers to deter problem flocks of birds is one of the non-lethal deterrent methods that is currently being tested by researchers.
"If that approach is proven to be effective and humane, the RSPCA would certainly welcome it.”
Meanwhile the college says the technique has proved effective this summer.
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Lasers used to scare geese
He told the Telegraph: “The Canada geese are big bully birds and they have scared off the indigenous birds, so there are none here now.
“Two years ago we had around 50 geese on the back lawn and the problem was getting out of hand because they were leaving excrement everywhere and attacking members of the public queuing for evensong in the chapel.
“We used a number of deterrents to drive them away and last year they seemed to find a better spot to go to, but this summer they have returned and are causing a nuisance again.
“The laser torches seem to be working at the moment and we will also oil the eggs in the spring to reduce the numbers for next summer.”
The comments follow a highly publicised protest by students last March, against what they perceived was a 'cull' of the geese - something the university strenuously deny.
A King’s College spokesman told the Telegraph: “The college has used a variety of non-harmful measures to deter the geese, and will continue to do so.”