Have your Cabbages been attacked? Are you left with stems but no green leaves, making them look rather skeletal? Then your problem is probably pigeons, they love all young Brassicas and very delicately and carefully nibble away at the tender green bits just leaving the stems and midribs! In gardens a lot of the damage is done very early in the morning so it may be difficult to spot them actually feeding.
The easiest way to protect your crops is to cover them with Netting. A simple frame over the bed to support the netting is very effective. A simple frame can be made with garden canes and Figo Connectors will join just about any size of cane from 8mm to 16mm.
Create your frame and simply drape your netting over the top and secure at the bottom. If Insect Netting is used instead of bird netting it will protect against just about everything that would love to dine on your crops.
If you prefer not to net your plants, 'Grazers' is an effective way help keep grazing birds or animals away from your crops. It works quite simply by making the plant most unpalatable to them. It has been used by farmers for quite a while with great success and is now available in a size suitable for the home gardener.
Grazers must be applied to the foliage of any growing plant where it is taken in systemically. Because it is nutrient based, it can be sprayed safely on Ornamental, Shrubs, Bedding, Fruit or Vegetable and lawns. It will in fact help repair any damage already caused.
It is odourless to the human nose, and safe for pets. Grazers being trace element based is beneficial to the plant and can be sprayed safely even on young plants at the earliest growth stage. It is effective against pigeons, rabbits, deer, geese and other grazing animals.