On several occasions I have been confronted by a sample as above. This damage was caused by Galahs or Parrots. The birds peck at the stems of the rose bush to obtain moisture from the sappy new growth of the rose bush. Usually at the top of the bush beneath the flower buds leaving the top 6 inches of the stem ( mm) hanging by a thin portion of bark, or if severed drops to the ground.
In most cases this damage occurs in late spring through summer and appears worse when in drought years. Properties where Galahs and Parrots are in large numbers will see this problem more regularly than most city dwellers.
Little can be done except the use of chilli or bitter sprays and these are effective only occasionally. Best control I have seen is to string through the garden numerous lines of fishing line. The birds try to land on the roses and their wings touch the lines which they cannot see and cause them to retreat.
Only other option I am aware of is bird scarers which may annoy the neighbours more than the birds.