In this task, you are given an article. Your task is to summarize the article in a sentence.
Q: The Scottish SPCA has appealed for information about five swans which are believed to be missing from the grounds of Provan Hall.
The severed head was found near the Glasgow east end parkland by a member of the public.
The charity said it was possible the birds had been deliberately lured from water before being netted.
Scottish SPCA Inspector Stacey Erwin said: "We believe that whoever is responsible has removed five swans from Provanhall House Loch and Bishop Loch.
"Swans can be lured over by slapping the water. We suspect these birds may have been netted and then removed from the water.
"This is a very serious and cruel act and we are keen to find the person responsible.
"We're encouraging the public to be aware of any suspicious goings on around Bishop Loch and Provanhall House and to report any information to our animal helpline."
A: 
The discovery of a swan's head in Glasgow has prompted an investigation into the disappearance of nearby birds.