Being a poultry species is risky.
For starters (quite literally), there’s the ever-present risk of being turned into a chicken nugget.
Scary though the thought of being turned into a nugget is, there is an even bigger threat out there for birds: bird flu.
The virus that can kill entire flocks.
But does the bird flu virus affect our backyard birds? Should you stop filling up the bird feeder? How can you tell if a bird has bird flu?
These questions, and more, are answered when you read on and learn what bird flu is and how it can affect certain species.
What is Bird Flu?
Bird flu, otherwise known as Avian Influenza, is a highly contagious viral disease that affects both domestic and wild birds.
Influenza. That sounds familiar, right?
Often called the common cold, influenza is one of the most common viruses on Earth.
But did you know, influenza doesn’t just infect us humans.
A whole range of animals can be affected by specialized influenza strains – including birds.
Bird flu is caused by a virus in the same family as the common cold; Orthomyxoviridae. Be honest, who stopped reading after “Ortho”…?
The disease occurs worldwide but different subtypes are more prevalent in certain regions than others. The most common kind of bird flu is the H5N1 strain.
Although there are many different strains of bird flu, most can be classified into two main categories:
- Low pathogenicity avian influenza (LPAI)
- High pathogenicity avian influenza (HPAI)
But more on this later, let’s give the brain a rest from these complicated terms.
Which Bird Species Are Most Affected?
Waterfowl – ducks, geese, cranes and storks – are natural carriers of the bird flu virus.
However, a wide range of wild bird species are susceptible to the virus. This includes hawks, eagles, falcons, owls, crows, vultures, shorebirds, game birds and seabirds.
Of the waterfowl species, mallards and Canadian geese are particularly susceptible.
If natural carriers of the virus come into contact with flocks of domestic poultry, such as chickens and turkeys, the bird flu virus is easily transmitted and can cause mass mortalities.
What About Backyard Birds?
Are our chickadees, robins and bluejays safe from bird flu?
The debate is still out on this one. Some scientists argue that bird flu can infect hundreds of bird species, including backyard birds.
However, it is unlikely that bird flu is causing mass mortalities in passerine birds. At least, for now.
Whilst bird flu may not kill our backyard birds directly, they could be acting as a bridge host for low pathogenicity avian influenza (LPAI) viruses from natural waterfowl carriers to commercial poultry farms. This is especially the case for common backyard birds, such as sparrows.
But the truth is we don’t really know.
In our ever-changing world – with climate change, habitat destruction and unregulated animal trade – we simply do not know how pathogens will evolve and how they may affect our backyard birds.
However, we shouldn’t worry too much just yet.
Less than 2% of all recorded global cases of bird flu are from passerine bird species – or, our backyard birds.
So, as long as you regularly clean bird feeders, and maintain good hygienic practices, there is no need to remove these from your garden. Afterall, many backyard birds rely on feeding stations for their survival.
How is Bird Flu Spread?
Bird flu is transmitted to other birds through direct or indirect contact via ingestion or inhalation of the saliva, mucus or fecal matter of infected birds.
The virus is also spread through predation and scavenging on infected individuals.
But surely birds don’t just go around pooping and spitting on one another? Surley?
The short answer – not intentionally.
However, there are several factors that influence the spread of bird flu.
Take modern farming practices, for example.
Intensive poultry production has increased in popularity in recent years. With thousands of birds crammed into small spaces, coming into contact with fecal or mucal matter is inevitable.
So, with individuals in cramped conditions, and with stress levels at an all time high, modern farming gives viruses a constant supply of new hosts.
In these conditions, viruses can spread like wildfire.
The bird flu virus is able to survive long periods of time in suboptimal conditions (i.e. low temperatures), and can be easily carried on farm equipment, spreading from farm to farm (so you can’t just blame migratory birds!).
As standard farming practice, once an individual has tested positive for bird flu, entire flocks of domestic poultry must be terminated, regardless if they are positive or not. This causes major economic losses and huge food wastages.
Other factors, such as the migration route of natural carriers, or reservoirs, also play a role in the spread of bird flu.
Many species of waterfowl are long-distance migrants, travel thousands of kilometers over a large geographical range, spreading the virus as they go.
But again, our backyard birds seem to be relatively unaffected by this trans-continental migrant virus.
Symptoms of Bird Flu in Birds
Right, back to those complicated terms. What do they mean?
First up, low pathogenicity avian influenza (LPAI). This virus typically causes little or no clinical signs. Oftentimes, symptoms include ruffled feathers and decreased egg production. Nothing too serious.
High pathogenic avian influenza (HPAI), on the other hand, is serious. This strain can cause severe clinical signs and possible high mortality rates.
In fact, once established in a population, HPAI can cause 100% mortality rates. Yikes.
But besides the mass deaths, are there any symptoms to be on the lookout for?
If a bird is infected with HPAI, there are several characteristics a bird displays (warning – more complicated terms on the way):
- Oedema of the head (swelling of the brain)
- Cyanosis of the comb and wattle (shortage or oxygen to the neck and throat, causing them to turn blue)
- Internal hemorrhages (mass bleeding within the body)
- Diarrhea
- Loss of appetite
- Lack of coordination and balance
- Unresponsiveness
- Closed and/or watery eyes.
If you suspect a wild bird – waterfowl or other – may have bird flu, keep your distance and call your state or the federal government, either through their state veterinarian or by calling USDA’s toll-free number at 1-866-536-7593.
Impacts of Bird Flu
With high mortality rates, bid flu can have devastating impacts on the poultry industry, farmers’ livelihoods, trade and wild bird populations.
When whole populations of domestic poultry are culled, not only will farmers suffer long-term financial loss, so does the wider economy.
Migratory host species, such as waterfowl, act as natural reservoirs for the bird flu virus, and contribute to the global distribution of the virus.
However, they are not totally immune to the virus. Many, including the Common Eider duck, have experienced vast die-offs. An estimated 15% of the Eider nesting population was wiped out in 2021.
New research shows that new strains of bird flu may even be jumping from migrating birds to mammals – causing a biodiversity crisis.
Humans, also mammals, may also become infected with the virus with devastating implications.
But hey, at least our backyard birds are okay.
How Can I Help?
Although bird flu mainly affects seabirds, raptors and poultry, it’s still good to avoid diseases spreading in your backyard.
Good hygienic practices are perhaps the most effective way to keep our backyard birds safe from potential viruses, such as bird flu.
Cleaning Feeders
Birds can get sick from moldy seed remnants or droppings that build up on feeder trays.
To prevent this, it’s recommended to clean your seed feeders every two weeks, or more frequently during periods of heavy use or in warm, damp weather.
To clean your bird feeder, scrub excess debris and soak in a diluted bleach solution. Using soap and water alone does not kill any pathogens on the feeder – that’s what the bleach is for.
Allow to dry completely before refilling, as moist conditions can promote the spread of certain diseases.
Disinfect Clothing
If you own poultry, even if it is a few chickens in the backyard, consider disinfecting shoes both before entering and after leaving their coop.
Disinfectants effectively reduce the spread of diseases such as bird flu.
Reporting
With new strains of bird flu constantly evolving, we need to know as much as possible about the spread of the disease. It is essential you report any dead or dying birds you find, but stay away from them – bird flu has, on occasion, been reported jumping from bird to human. .
Final Thoughts
Bird flu is a highly contagious strain of influenza that affects hundreds of different bird species across the globe.
Waterfowl can carry and disperse the bird flu virus without any symptoms. However, other bird species such as domestic chickens and raptors get severe symptoms and rapidly die.
Depending on the severity of the virus, bird flu can have a 100% mortality rate in flocks of birds.
Although the virus mainly affects poultry, waterfowl and raptors, our backyard birds may be acting as a bridge host, allowing the pathogenic bird flu virus to be transmitted between species.
As long as you maintain good hygienic practices, such as regularly cleaning bird feeders, the spread of bird flu can be controlled and minimized.
And remember, if you suspect a bird may be infected with bird flu, keep your distance and inform your state or federal government.
