Pigeons can cause damage to plums and greengages particularly in April. At this time of the year, when the first new, tender leaves are emerging, they attract pigeons, which can be present in large numbers particularly in areas where field rape is grown. The pigeons show a great desire to vary their food source. After having grazed the rape fields, the pigeons will move for a while to the nearest hedge cover. From that point they will attack any type of plum or greengage, severely damaging any blossom or young green leaves.
The net result is that the crop prospects of those trees will be set back greatly and may result in no crop at all. Anything that can be done to scare the pigeons away is worth trying. A mixture of various deterrents is better than just one.
The length of the period during which the trees are at risk will greatly depend on temperatures and type of weather. A long cold spell in early spring is the most damaging situation in terms of pigeon damage, because of the shortage of fresh green growth.
How to protect against pigeon damage on plums
Without blossom, there can be no fruit set, and so no fruit! Therefore if damage is only slight, no action needs to be taken. If the cold period continues, pigeons are capable of literally stripping off all the blossom. Black cotton threads, woven through the flowering branches, will usually stop the damage. Just wind it around the tree (slip the spool onto a rod or dowel to make things simpler) so that the threads are about six inches apart. What happens is that the bird flies towards the tree, doesn’t see the thread, touches it with its wing, gets a fright, and flies off. No damage to the bird is done, and it helps save the blossom!