Dozens of swans and geese have died in an outbreak of avian botulism caused by the heatwave.
The Swan Sanctuary in Shepperton is caring for around 300 water birds, many suffering from the deadly illness and most rescued from ponds and lakes in the capital.
The extreme heat means there is less oxygen in water, providing the perfect breeding ground for the botulin toxin.
Dorothy Beeston, founder of the Swan Sanctuary, told the Standard: “In the last three or four weeks we have seen a huge spike in the number of birds being brought into the hospital with botulism. It’s been dozens of calls a week, which is just terrible.
UK August Heatwave - In pictures
“Hot weather often causes an outbreak but this is one of the worst I’ve seen in the 39 years we have been set up. We lost two swans in the first week but they were very poorly. Lots of birds are on drips and they seem to be doing well. But we can’t send them back [to the water] until the toxins have cleared. All we can do is pray for rain.”
Affected birds are unable to use their legs or fly, and their neck muscles can be paralysed. They commonly die from respiratory failure or drowning.
Rescuer Steve Knight said that east and central London were the worst-affected areas. “We’ve been called out to Limehouse and Dagenham on a number of occasions,” he said. “On one call to Essex we found about a dozen birds already dead and the council had already taken some away on top of that.
“But when we get them to the hospital here and get them on a drip they have a good chance of surviving.”
The risk to humans from the botulism strain is said to be low.
