Ainsley Tucker, of Dunedin, asks :-

I have a keen interest in helping the city and bush birds through the winter months. I put out sugar-water and seed on a daily basis and also bread. I was recently told to be careful about feeding bread to the birds when they begin nesting because it can actually harm the baby birds when the parents feed them. Is this true? I would hate to think I was harming them rather than helping them.

Karin Ludwig, a zoologist, at the University of Otago responded.

You are doing a great job by offering a variety of food. However, there are a few things to watch when feeding birds.

Firstly, offering fresh food and having a clean feeding station is most important. Changing water daily is crucial as sugar water encourages the growth of nasty bacteria such as E. coli, which can lead to food poisoning. Furthermore, Salmonella is spread by drinking water contaminated with faeces. Unless the birds can’t poo in the water and it is cleaned daily, this is exactly what happens – the birds poo in the water they drink and therefore share their salmonella around.

There are a couple of reasons why feeding bread to birds is not ideal. Firstly, it can cause crop impaction. A crop is a sac of muscle tissue halfway down a bird’s oesophagus. This is where all food is stored initially. From there the food needs to pass through a small opening into the intestine, the gizzard and eventually the stomach. The food does not get ground up until it is in the gizzard. If a bird eats too much bread it can sit in the crop as a big doughy lump, unable to pass down to get processed.

Secondly, bread is like junk food to birds. Although they love eating it, it causes nutritional deficiencies as it lacks calcium and phosphorous. This can lead to metabolic bone disease, which makes bones brittle.

The best thing you can do is to look up the bird’s natural diet in your bird book. Blackbirds eat lots of worms – maybe you could give your bread to your worm farm and then feed the worms to the birds? And if you are growing broccoli pick off the caterpillars and put them on your bird feeder - the birds will love it!