Why it is absolutely vital to keep bird feeders and feeding areas clean

After cats, the biggest single reason for the premature death of garden birds is disease caused by dirty bird feeders and the areas around and below the feeders not being kept clean. Some bird species are particularly prone to disease, and at the top of this list would have to be the Greenfinch.

A relatively recent study undertaken by the Zoological Society of London, the British Trust for Ornithology (BTO), and Fera Science, analysed over 25 years’ of data and found negative changes in some British bird populations, which the scientists believe were at least partly caused by disease spread at garden bird feeding sites. More recently, the RSPB has reviewed data on bird feeding and the negative impact poor hygiene and other factors has had on some populations of songbird species.

However, it must be stressed that if the following guidelines are followed and bird feeders and feeding areas are kept clean, cases of disease can not only be kept to a minimum, but a very positive difference can be made to populations of many garden bird species. Indeed, the studies outlined above also noted the positive impact of feeding garden birds on the numbers of some species.

Common diseases in garden birds

Trichomonosis

The most common disease is now likely to be Trichomonosis, which has long been present in doves, pigeons and birds of prey (though often not killing them) and often also referred to as ‘Canka’. But in the last few decades Trichomonosis has spread to finches – in particular the Greenfinch – and caused long term declines as once a bird has been infected, then death is a near certainty. Chaffinches, Siskins and Bullfinches are also very much affected by the disease. Trichomonosis is caused by a single cell parasite, Trichomonas gallinae, which, once picked up by a bird through infected food or water, lives in the mouth and crop. The parasite causes lesions which eventually stop the bird swallowing and therefore leads to its death.

A bird can become infected by picking up dropped food in saliva, which contains the parasite from an already infected bird, with the dropped food occurring because the infected bird is unable to swallow. However, outside of a host bird, the parasite can live for much longer in conditions such as damp and decomposing food waste (where fresh but infected food might land), than it can on a dry and clean surface. So this is why it is absolutely critical to keep feeders and feeding areas clean, as by doing so the risk of transmission to another bird is greatly reduced. The parasite can also live longer in water such as that in a bird bath. So in short, by keeping feeders, feeding areas and bird baths clean, you greatly reduce the amount of time the lethal parasite can stay alive.

Salmonella

Salmonella (Salmonellosis) usually starts because husks are left to rot on the ground below a feeder, in particular black sunflower seeds, or if the feeder becomes clogged with waste or is just very dirty – therefore allowing the Salmonella bacteria to breed and multiply. The disease is then typically spread through a bird’s droppings, where the Salmonella bacteria remain and then infect other birds when they come into contact with it – e.g. from a bird bath or where the droppings have contact with food. This makes bird tables a particular risk because of the likelihood of infected bird droppings coming into contact with food.

Other diseases

E. coli, also a bacterium, can also be a problem, but this is probably less common than Salmonella.

A more recent disease which has spread from the continent, is the Usutu virus which largely just affects Blackbirds – and mainly in the south and south east of England. This is a mosquito-borne virus, with the main precaution you can take being to keep water butts covered and to change the water in bird baths very regularly.

Avian flu largely doesn’t affect songbirds (mainly seabirds and waterfowl) but none the less it is technically possible that it could be present and transmitted from bird feeders.

How to minimise the risk of your garden birds catching and transmitting diseases

Keep bird feeders and accessories clean

Clean all bird feeders with hot soapy water and /or a proper feeder disinfectant and do so on a very regular basis – ideally once a week as an absolute minimum. (Have a look at the video above for best practice and tips.) This is especially the case for seed feeders with perches, because that’s where waste and disease can particularly be present. For this reason, dismantle the feeder first to ensure all components can be properly cleaned. If you have an old feeder which can’t be dismantled, then consider a new one which can.

Suet and peanut feeders are generally less of an issue, but still require very regular cleaning. In all cases after cleaning, rinse the feeder with clean fresh water before allowing the feeder to completely dry before use. As the process takes some time and to make it both easier and ensure your birds can still feed, the best approach is to have at least two feeders of each type but only one of them in use – so put the clean one up as you take the other one down for cleaning etc.

Avoid using bird tables and other feeders with flat surfaces

Because of the flat surface of bird tables and also the fact that this is generally made of wood, they can present a particularly high risk of harbouring disease. Keeping bird tables very clean is therefore especially important, and to the point that we recommend NOT using a bird table at all if you're not in a position to carry out regular and thorough cleaning – which ideally should be once per day. The same also applies to other flat feeding surfaces, even if they're plastic or metal, such as ground trays and seed trays which fit below tube feeders.

The other issue is not being able to easily dry the surface of a wooden bird table, and especially during the winter months. So this is another reason not to use one, as damp surfaces allow the parasite which causes Trichomonosis to live much longer.

Clear up husks and waste

Clear up husks and other waste including droppings below feeders very regularly and ideally every few days, or even every day if waste is quickly building up. To help minimise this waste, use a seed or seed mix which has no or very little waste such as Sunflower Hearts or a husk-free bird seed mix.

Move feeders around your garden regularly

In conjunction with clearing waste below feeders, a further important measure is to move feeders to a different position in your garden on a very regular basis. This is because even after you’ve cleared the waste up, the ground can still remain contaminated – in particular on a lawn or rough grass area where tiny pieces of waste will remain. If you have a small garden and it’s therefore not possible to move feeders to different positions, then a way around the problem is to site the feeders over a patio or other hard standing area. This will then make it much easier to clear up waste, plus the surface can be thoroughly washed to ensure it’s completely clean.

Throw away uneaten bird food

If food isn’t eaten in feeders, then throw this away and clean the feeder thoroughly. This is necessary because even if the feeder isn’t exposed to large amounts of rainfall, moisture in the atmosphere will still lead to the food becoming damp – which will then make it deteriorate and therefore potentially attract bacteria and mould. Also worth noting that the main reason some bird food goes uneaten is that it’s poor quality and therefore not appealing to birds. So avoid the problem by only providing the sort of high quality food we sell at Vine House Farm.

Avoid feeding stations

Feeding stations have long been popular because they provide a single structure from which to hang bird feeders. However, we and the RSPB now see them in a negative way, because the concentration of feeders and resulting high number of birds in one place, is very likely to increase the risk of disease transmission. So the recommendation now is to spread feeders out around a garden (also note the point above about moving feeders around and not keeping them in the same place for too long).

Keep food and feeders dry

Even if a feeder and the food in it is clean and not contaminated in any way, moisture on its own can present a risk because the parasite which causes Trichomonosis can live longer in a situation where water is present compared to one which is dry. A simple way you help keep feeders and the food within them dry, is by using a product which also acts as a rain guard like this one or one that fits over the feeder tube like this one.

Change water regularly

Change the water in bird baths very regularly – ideally every day and in particular in the summer months – and clean the bird bath thoroughly using a special disinfectant. It is vital to ensure the bath is then thoroughly rinsed with clean water to ensure no disinfectant remains. The bird bath should also ideally be allowed to dry before refilling it, as this will also help ensure that the parasite which causes Trichomonosis won’t survive the cleaning process. Citrosan can also be added to the clean water to reduce the risk of contamination occurring.

Wear gloves & wash hands

And don’t forget about your own health! Wear rubber gloves when cleaning feeders and bird tables, or if you need to handle a sick or a dead bird in your garden. Always wash your hands when you've finished any work to do with feeding birds and cleaning feeders.

How you can tell if a bird is sick and what to do

Certainly for songbirds such as species of finch, you can tell if a bird is sick by the following symptoms:

  • Lethargic behaviour which is likely to include not immediately flying off as you approach it
  • Puffed-out body feathers
  • Specifically for Trichomonosis, uneaten and wet (from saliva) food around its bill

To help scientific research, it’s important to report sick or dead birds you find in your garden, which you can do through this link https://www.gardenwildlifehealth.org/

Unfortunately, there is generally nothing you will be able to do to save an infected bird. If you find a dead bird and need to dispose of it or provide it as a sample having used the link above, then always wear gloves when handling.

If you only find one sick or dead bird, then it could just be a one-off incident so you can continue feeding your garden birds as normal. However, any more than one then you should stop feeding immediately and remove all feeders. If you have neighbours who are also feeding birds, then it’s important to make them aware of what you’re doing and suggest they do the same, as otherwise the disease issue will just move to an adjacent garden, rather than allowing birds to disperse more widely and therefore reduce the risk of spread.