The Bucks Herald launched an inquiry after we were contacted by a number of readers who discovered the dead birds – all in the Southcourt area of the town.
On Tuesday afternoon a girl found a group of nine dead gulls on the green off Ellen Road near Mandeville School.
Aylesbury Vale District Council's environmental health department was informed and the birds were collected. It is thought they may have had broken wings.
In the afternoon workers from St Tiggywinkles Wildlife Hospital were called out to collect a black-headed gull from Prebendal Avenue. It had a badly broken wing. Then on Wednesday one was found on Cornbrook Road with a broken wing and broken leg. There were no signs of any being shot.
Sue and Les Stocker, from the hospital, said to find this many in two days – especially the group of nine – is out of the ordinary.
Mr Stocker said: "What's causing this, we do not know. They can get into trouble with wind and getting the odd gull is not unusual, but not 11."
He said from experience of working with birds in the Shetlands they love windy conditions, but they could have been caught in a small tornado.
Barry Gromett from the Met office suggested this might not be the case though. He said: "Last Wednesday was a fine afternoon across England and Wales and certainly no suggestion of tornadic activity. On Tuesday there may well have been some squally winds associated with heavy rain or showers, but again I think a tornado unlikely."
Grahame Wedge at the Royal Society for the Protection of Birds (RSPB) was suspicious when he heard the story.
He said: "I have been doing this job for a number of years and this is the first time I have come across anything like this.
"If there was a deliberate act it is mystifying as to how a crime like this would be committed because you would expect them to be shot.
"It seems to me they must have been killed somehow accidentally or deliberately. There is obviously something quite suspicious about this that warrants investigating."
He said it is an offence to kill any bird.
Anyone who finds dead or sick birds can call the Department of Environment, Food and Rural Affairs (Defra) helpline on 08459 33 55 77 or Tiggywinkles on 01844 292 292.