A swan nest has been disturbed and the swan eggs deliberately stamped on in an attack near the Leeds Liverpool Canal.
West Yorkshire Police's Wildlife and Rural crime team said that the suspect stamped on every single egg in the nest.
All the eggs were completely destroyed in the attack, which took place at Dockfield Road in Shipley.
The incident, which happened at some point between Tuesday, July 2 and Thursday, July 4 is believed to have been deliberate, according to the Yorkshire Swan & Wildlife Rescue Hospital.
In an appeal on Facebook, the animal rescue charity said: "Between the afternoon of Tuesday 2nd July and the morning of Thursday 4th July, a nesting pair of swans appear to have been deliberately disturbed and their eggs smashed on the pathway close to their nesting spot.
"This incident occurred off the Leeds Liverpool Canal on Dockfield Road in Shipley. The incident has been reported by our team to West Yorkshire Police as a wildlife crime."
In an update on Wednesday, July 10, they reassured the concerned public that the swans are "perfectly well" although a little subdued.
They are monitoring the birds.
The charity also dismissed suggestions that other animals may have been responsible for the damage and reaffirmed that they are "highly suspicious" that it was deliberate.
They added: "It has been suggested that other animals may have predated the eggs.
"This does indeed naturally happen very occasionally, but given our vast experience, we would have expected the eggs to have been carried and consumed a distance away from what would have been a very distressed pair of swans, not leaving most the contents of the eggs within a few paces of the nest. The eggs were also ‘flattened’, suggesting they may have been stood on.
"We were highly suspicious this may have been a deliberate incident when first reported, given in recent months we treated a swan rescued from the very same stretch of Canal with injuries from an air rifle pellet. The bird made a full recovery.
"Rather optimistically, we understand significant evidence has since come to light which is being forwarded to investigating wildlife officers at West Yorkshire Police. The evidence now suggests this was a deliberate attack."
Anyone with information is asked to contact the police quoting crime reference 13190347306.