Due to recent Avian influenza (bird flu) outbreaks in captive bird populations, an Avian Influenza prevention zone was declared across the UK at the start of November. There have also been multiple findings of bird flu in wild birds from sites across the UK.
As a precaution, if you find dead wild waterfowl (swans, geese or ducks) or other dead wild birds (gulls or birds of prey) in Nene Park, please report them to the Duty Ranger on 07860 308081. For any birds found outside Nene Park, please call the DEFRA helpline on 03459 335577. Although the risk of contracting the disease from a wild bird is very low, you are advised not to touch any sick or dead birds.
Birds reported may be removed by DEFRA for testing, however not all birds will be collected. 
For full information regarding the current situation, please visit: https://www.gov.uk/guidance/avian-influenza-bird-flu