Why clean feeders matter more than you might think

A well-stocked feeder is one of the simplest ways to bring life into a UK garden. Goldfinches squabbling over nyjer, a pair of great tits darting in for sunflower hearts, the sudden flash of a siskin in winter — it is a genuine pleasure, and it does real good for birds that are struggling with habitat loss and unpredictable weather.

But a feeder is also a gathering point. Dozens of birds may visit the same perch in a single day, and everything they carry on their feet, feathers and beaks stays behind on the surfaces. Droppings, regurgitated food, saliva and damp seed create a warm, sticky film that bacteria and parasites thrive in. Two illnesses in particular cause serious losses in British gardens: salmonellosis, which is spread through contaminated droppings and food, and trichomonosis, a parasite that has hit greenfinches and chaffinches especially hard since it emerged in the mid-2000s. Both are made far worse by dirty feeders and crowded, damp feeding stations.

The reassuring news is that this is one of the few wildlife problems you can fix almost entirely with a bowl of hot water and half an hour of your time.

How often should you wash your feeders?

Treat once a fortnight as your absolute minimum, all year round. In practice, many gardens need more than that. Wash weekly from April through September, when warmth speeds up bacterial growth, and weekly in any mild, damp spell in winter too.

Increase the frequency if any of these apply:

• You are feeding a lot of birds, or have several feeders close together.
• Seed or peanuts have got wet and started to clump or smell musty.
• You have seen a bird looking unwell at the feeder.
• You are putting out soft foods such as suet balls or soaked mealworms, which spoil quickly.

If you have more than one feeder, buy a spare. Rotating them means one can be soaking and drying thoroughly while the other is in use — far better than rushing a wet feeder back out because the birds are waiting.

The fortnightly wash: a simple routine

You do not need specialist equipment, but a dedicated bottle brush and an old toothbrush make the job much easier. Work outside or over a sink, and wear gloves if you have any cuts on your hands.

• Empty the feeder completely and bin the old food. Do not put it back, and never add fresh seed on top of old.
• Dismantle it as far as it will go — perches, ports, bases and lids all harbour grime.
• Wash in hot soapy water using ordinary washing-up liquid, scrubbing every crevice, port and feeding hole with a brush. Pay attention to the inside of tube feeders, where mould collects out of sight.
• Disinfect if you have had disease in the garden or feed a lot of birds. A bird-safe disinfectant, or a diluted thin household bleach solution of one part bleach to nine parts water, works well on plastic and ceramic. Rinse far more than you think is necessary — bleach damages metal, so keep it away from feeders with metal fittings.
• Rinse thoroughly in clean running water until there is no trace of soap or disinfectant smell.

While you are at it, give the ground beneath the feeder a sweep. Hulls, droppings and spilled food build up into a soggy mat that birds pick through constantly. Move the feeder to a new spot every few months and let the old patch rest.

Drying and refilling properly

Damp is the enemy. A feeder refilled while still wet will grow mould within days, and mouldy food is a genuine hazard. Allow feeders to dry fully — air-drying in sunshine is ideal, or stand them on a draining rack, upside down so water can escape. A quick wipe with a tea towel is not enough; the crevices stay damp.

When you refill, use only fresh, dry food from a sealed container. Check that seed is not clumping, dusty or smelling sour. Never put out mouldy bread, leftovers, or salty and cooked foods. Choose feeders with good drainage and a lid, and hang them so they are not permanently shaded and dripping.

Feeding habits that reduce risk

• Spread things out. Several smaller feeders around the garden beat one crowded station, reducing contact between birds.
• Clean bird baths too. Scrub and refill every few days — a dirty bath spreads disease just as effectively as a dirty feeder.
• Keep a tidy base. Use a tray or sweep regularly, and avoid feeding on a permanent lawn patch that never dries out.
• Store food dry in a sealed bin in a cool place, and use it within a few months.

Spotting disease early — and knowing when to stop

Learn what a sick garden bird looks like: fluffed up and hunched even in mild weather, unusually tame, sitting quietly on the ground, with food stuck to the beak or droppings matted around the vent. Vomiting seed, or a bird that seems to be choking, can indicate trichomonosis.

If you see any of these signs, take your feeders down for at least two to four weeks and clean them thoroughly. This sounds drastic, but it disperses the birds and breaks the cycle of transmission. Empty and disinfect bird baths as well, and report what you have seen to a national garden bird health survey so that patterns can be tracked.

Then start again slowly, with sparkling clean feeders, fresh food, and a good routine. A little hot water and diligence is a small price for the company of healthy birds.