Feeding station hygiene is of paramount importance as the build up of unused food and bird droppings in such a relatively small area can lead to various issues. Birds are susceptible to disease when conditions allow the disease to spread. Whilst it may not be possible to stop birds getting diseased due to the fact that they are wild and cannot be contained in a "hygenic" state, I think it is our responsibility to keep our garden as free from conditions for disease to be SPREAD to a minimum. This is achieved with various means.
The simple fact of the matter is that we have a very "unnatural" ocurrence when we choose to put food out for the birds as the amount of food and birds which all abound in a very small space causes a state that would not normally occur in the wild. This amount of food causes a large build up whether that be uneaten, spilt or old, it still causes a problem.
This build up of food can lead to other problems such as vermin and this is as good a reason as any to keep food areas clear of any food for long periods.
The unusually high proportion of birds visiting to take advantage of the food on offer also leads to a build up of droppings and other fluids like saliva. This is one of the biggest spreader of any disease outbreak as the disease can live outside of the bird for, in some cases, quite some time. This spread of disease is passed on through several means some of which being the eating of spilt food that may be contaminated with droppings. The same outcome can happen when saliva is left on feeders as birds tend to wipe excess food from the beaks and the feediing pegs and other items within the garden. This problem with saliva is exaggerated as an ill bird will often produce excess saliva. A diseased bird also ofen cannot swallow leaving the bird to regurgitate food around feeding areas.
With this in mind I will list a few items that I think may be helpful.
A) Since the risk of disease transmission is related to the numbers of birds congregating together, one of the best things you can do is to use several feeding sites within your garden and to not just place all your feeders in one spot. This helps to disperse the feeding birds over a larger area and reduces the potential for disease build-up. It is also important to move your feeding sites periodically, especially those where you feed directly onto the ground. Allowing areas to ‘rest’ will help to reduce levels of contamination. Finally, think about where you position feeders in relation to other garden features. For example, it is best to avoid placing a bird table under a tree in which birds perch or roost, since it soon becomes heavily contaminated with droppings.
B) Hanging seed feeders typically retain the food within a clear plastic tube and this means that there is a very low risk of the food becoming contaminated with droppings.
Bird tables, where birds actually stand on and amongst the food, have a greater risk of contamination. Whilst this implies that hanging feeders are better from a disease prevention point of view, it is worth remembering that many species are unable to use hanging feeders and that, with good hygiene practice, bird tables or ground feeding trays are just as safe.
When choosing a feeder or bird table, look for one that reduces the risk of contamination and keeps the food dry. If food becomes damp, then it is likely to be more susceptible to moulds and contamination by other harmful agents.
Some mesh peanut feeders leave the peanuts open to the elements and the nuts may become damp and deteriorate more quickly than other types of food held in tube feeders. This means that you should pay particular attention to the peanuts you provide to ensure that they are fresh and safe for the birds. One of the best ways to ensure this is to only put out a small quantity of peanuts so that fresh ones have to be put ut every few days.
C) Regular cleaning and disinfecting of bird tables, bird baths and hanging feeders is an important part of good hygiene practice when feeding garden birds. Alongside these measures, it is important not to provide more food than birds need. Ideally, bird tables should be swept clean each day to remove droppings and any uneaten food.
Tables and other feeding surfaces should be disinfected on a regular (weekly or fortnightly) cycle using an appropriate disinfectant such as Ark-klens or Tamodine-E, followed by thorough rinsing and air drying before subsequent use.
Cleaning equipment should not be used for other purposes and should be kept and used outside. Rubber gloves should be worn for the purpose, and hands and forearms should be washed thoroughly after handling or cleaning feeders. The ground beneath feeders may be kept clean by regular sweeping and disinfected through the use of products such as Gardenklens powder. Bird baths should also be cleaned in a similar manner.
D) Purchase foods from reputable sources and from retailers that regularly check their peanut supplies for aflatoxins. Under some circumstances, stored foods (e.g. peanuts and cereals) can be attacked by moulds that produce very dangerous toxins. Foods should be stored in a clean, dry and cool environment inaccessible to pests. This will minimise the risk of fungal or bacterial contamination and will also avoid encouraging rats and mice. Keep a regular check on food provided in hanging feeders and try not to overfill feeders, otherwise uneaten food may remain in feeders for too long a period.
E) If you encounter what you think is a diseased bird, start by making sure that your hygiene measures are up to date. Thoroughly disinfect your feeders and bird table and consider moving the site at which you feed, to reduce the risk of contamination.
One often-asked question is whether to cease feeding altogether. If, by ceasing feeding, the birds are likely to disperse to feed at lower densities on naturally occurring foods in the local environment then it may be sensible to cease feeding for a short period. If the birds are dependent on the food being supplied or if, by ceasing feeding, they may be forced to a more problematic feeding station nearby, it is best to continue feeding – especially if you are confident in your hygiene practices.
Treatment is rarely an appropriate option. A bird that is so sick that it can actually be caught by hand may require euthanasia to prevent further suffering. Although wild birds are protected under the Wildlife & Countryside Act 1981, there is provision within the act to allow the euthanasia, by a humane method, of wild birds that are moribund.
Euthanasia can be carried out by a veterinary surgeon through the administration of an overdose of anaesthetic. In emergencies, garden birds can be euthanased by a strong and wholly committed blow to the back of the head with a suitably hard and heavy implement. Death must be confirmed by the absence of breathing and absence of a blink reflex when the surface of the eye is touched.
F) Wild birds are susceptible to a range of different diseases, some of which are more commonly reported than others. Among the diseases reported from birds using garden feeding stations are those caused by Salmonella and E. coli bacteria. These are of particular concern because they are infectious and may lead to severe outbreaks under certain conditions.
Although precise symptons may vary between disease (and indeed between species and individual birds) there are some general signs that may alert you to the fact that an individual is suffering from some form of disease. Affected birds may appear lethargic and reluctant to move away from the feeding station. They may also show a fluffed-up appearance or difficulty in swallowing food/water.
Anecdotal evidence suggests that some bird species may be more susceptible to disease than others. Certainly, Greenfinches, Chaffinches, Siskins, House Sparrows and Collared Doves appear to be the most commonly reported victims of diseases. This may, in part, reflect the gregarious nature of these birds and their tendency to feed in flocks.
SALMONELLOSIS
Within the UK, this disease is most commonly caused by the bacterium Salmonella typhimurium, with most deaths caused by the strains DT40 and DT56. Most outbreaks of the disease are reported from December through to April, with transmission occurring through faecal contamination of food at feeding sites. The main species affected appear to be Greenfinches and House Sparrows but a wide range of other species have had confirmed cases of Salmonella attributable mortality.
Outbreaks have also occurred in Canada and the United States (both DT40), New Zealand (DT160) and at garden feeding stations in Norway (DT40 and U277). In the Norwegian outbreaks, the main species involved was Bullfinch.
Salmonella bacteria are able to survive within the environment and, under suitable conditions, may multiply. The winter peak in reported cases within the UK, may simply reflect the presence of birds at garden feeding stations and possibly the increased numbers of birds gathered together. However, it is possible that the stresses induced by winter weather conditions may lower birds' immunity and increase their susceptibility to infection.
Affected individuals appear fluffed-up, lethargic and reluctant to move away from the feeding station. Many individuals are reported as being visibly ill for a number of days prior to being found dead. The disease causes damage to the internal organs and, even though individuals may continue to feed, damage to the gullet may prevent food reaching the stomach.
Samonella typhimurium can cause serious disease in humans and it is essential that sensible hygiene precautions are taken when cleaning feeding areas used by birds or removing and disposing of carcases. Domestic pets have been known to acquire the disease from eating infected birds.
COLIBACILLOSIS
Colibacillosis is caused by the bacterium Escherichia coli (more familiarly known as E.coli), with most incidents in garden birds associated with the strain O86. The timing of outbreaks within the UK appear to be slightly different from the pattern seen in Salmonella, with most cases seen in a recent Scottish study occurring in the months March to May.
Affected individuals appear fluffed-up, weak and lethargic. E.coli does not damage the internal organs in as visible a manner as Salmonella but the toxins that it produces may prevent the digestive system from working correctly.
Although human illness from E.coli O86 is uncommon in the UK there is the potential for spread to humans. As such, it is essential that sensible hygiene precautions are taken when cleaning feeding areas used by birds or removing and disposing of carcases.
TRICHOMONIASIS
Trichomoniasis is caused by the single cell parasite Trichomonas gallinae. It is also known as 'pigeon canker'. This reflects the fact that pigeons and doves appear the most susceptible to this disease and are the main carriers. Other species of birds, including other garden birds, game birds and raptors may also be affected. During severe outbreaks, it seems likely that quite high proportions of affected local Collared Dove populations may die, highlighting the particular susceptibility of this species to the disease. Young birds appear more susceptible than adults.
The infection is thought to be spread via food or drinking water freshly contaminated with saliva or (possibly) droppings from an infected individual. Trichomonas appears unable to survive outside of its host for more than a few minutes. Infected individuals may appear lethargic and often dribble or show difficulty in swallowing.
Although the various species of Trichomonas that affect wild birds do not affect mammals, they can cause disease in domestic poultry.
GROWTHS ON LEGS AND FEET
A number of different agents may cause swellings on the legs and feet of wild birds. Some of these are caused by mites of the genus Knemidocoptes and result in scaly legs. The 'scales' themselves are dry encrustations made up of material produced by the bird in response to the irritation caused by the mites, together with skin debris thrown up by the mites as they burrow into the tissues. As well as forming on the legs, the 'scales' may also form around the beak. These mites are members of a wider family of mites that cause mange in domestic animals and scabies in humans.
Another cause of warty growths is the Fringilla papillomavirus which affects Chaffinches and Bramblings. These growths may vary in size from small nodules to larger warts that engulf the whole leg. The warts develop slowly over a long period and affected individuals may otherwise appear quite healthy. Some individuals may become lame or lose affected digits.
Wounds on the feet may become infected by bacteria, resulting in the formation of abscesses - sometimes referred as 'bumblefoot' by poultry breeders.
AVIAN POX
Avian pox is another possible cause of wart-like growths on a bird and can occur in two forms. In the most common form (cutaneous pox), wart-like growths form around the eyes, beak and on unfeathered skin, including the legs. This often results in difficulty in breathing, feeding and seeing. In the less common form of pox (diphtheritic pox) the growths form inside the mouth, throat, lungs and windpipe. This results in difficulty in swallowing and breathing. Birds suffering from the disease (in either form) usually appear weak and emaciated.
The disease is both highly contagious and highly infectious, with the ability to remain in dried scabs for long periods of time. It is thought that the disease may be a significant mortality factor in some songbird populations worldwide during winter but its impact within Britain is unclear. The hygiene precautions suggested for feeding stations elsewhere in these webpages should help to limit the spread of the disease.
Poultry are susceptible to the disease and, Worldwide, many are vacinated against pox.
Avian influenza
Avian Influenza Update: 15th June 2006
Latest Update
There have been no cases of Highly Pathogenic H5N1 Avian Influenza since the dead Whooper Swan found in March at Cellardyke, Anstruther, Fife. Restrictions relating to this case were lifted from May 1st 2006. BTO staff continue to provide advice concerning wild birds to government agencies in conjunction with the H5N1 situation.
The recent cases of avian influenza in poultry in Norfolk have involved a low pathogenic H7N3 strain of the virus. This occurrence is entirely unrelated to the cases of H5N1 in Scotland and elsewhere. Nonetheless, the advice of BTO and other ornithological advisors has been sought by the government in considering the possible origin and potential further spread of this strain.
Birdwatchers are asked to help by remaining vigilant for unusual bird mortality and reporting it to Defra as appropriate, on 08459 335577.
Further advice and information will be issued as the situation develops.
Current situation
Since the spring, the number of new H5N1 cases in Europe has declined greatly, with most recent outbreaks being from Romania. Further east, outbreaks are still being reported from China amongst both poultry and wild birds (often including large numbers of Bar-headed Geese).
How did avian influenza reach western Europe?
H5N1 has been circulating in Asian poultry populations for several years now. During the last year, as the virus spread from its original focus in south-east Asia to central Asia, then the Black Sea region, and more recently into West Africa, the means of its transmission were unclear. Whilst there was much speculation about the role of wild birds, there were also clear grounds for suspecting that movements of poultry and cagebirds were at least partly responsible. However, the cases in western Europe in late winter 2005-06 point very strongly towards recent spread by wild birds following cold-weather influxes of birds from further east.
H5N1 has now been confirmed in domestic poultry in France and Germany. The precise means of transmission are still not clear. There have been no recent cases of H5N1 in domestic poultry in the UK.
What to do
Birdwatchers can be of great assistance in staying alert for unusual cases of mortality or sickness in wild birds. Contrary to some suggestions, there is clearly no need to report every single dead bird that you come across. However, if you do notice unusual mortality (e.g. several dead birds in unexplained circumstances) then please contact Defra immediately on 08459 335577. In addition, Defra are interested in all reports of single dead swans.
It should be stressed that H5N1 is a disease of birds. It is of great concern for the poultry industry but does not appear to be a major issue for human health in the UK. Whilst deaths have occurred in other countries, the numbers of cases have been very low and have been confined to people in very close contact to infected poultry. The advice is that there is no danger from eating well-cooked poultry and there is certainly no danger from normal birdwatching activities. Sensible basic hygiene should be practised if you do come into closer contact with birds