Red Algae In Your Bird Bath? This Is What To Do

Something I have noticed since getting into feeding garden birds is the water in my bird bath turns red. I also noticed it in a disused plant pot in the corner of the garden. What is that red stuff in my bird bath? I wanted to find out where it comes from and, more importantly if it is harmful to birds. I looked into this and found out exactly what I needed to know. Here is what you can do about it.

The red substance and colouration you often see in a bird bath is caused by a type of micro-organism – Haematococcus pluvialis to be precise. It is a type of algae that occurs in water and the red colour is due to an active pigment, which is believed to reflect the harsh sun light. Not surprising then, this algae can withstand the harshest of conditions. 

Is Red Algae Harmful To Birds?

Algae in a bird bath is not believed to be harmful to birds. Birds and other wildlife generally have very different digestive systems to us humans and can eat all kinds of things that would make us ill or, at worst, kill us.

Birds need a place to bath and to drink. A bird bath with algae in it will not harm a bird but it will put the bird off from visiting again. I would be the same – if I go to a restaurant and the service is bad, the food is nice but why would I want to go back? It is the same for birds and we need to make sure that if we go to the trouble of feeding them and providing fresh water, we maintain these things for their benefit.

Algae in water is completely normal and in certain situations it is a sign that we need to change the water sooner. It is very important that you do not use any kind of algae controlling chemical or algae killer in a bird bath. These can be fatal to a bird.

How To Get Rid Of Red Algae In A Bird Bath

The only way to get rid of red algae in a bird bath is to clean it really well. Below are some useful methods in how to do this. It is important to know that there are few ways, if any, you can actually 100% prevent the red algae from appearing. Whilst you cannot completely prevent it, there are ways to manage it so it doesn’t become a persistent problem.

Move The Bird Bath To A Shady Place

The red algae thrives in the hot sunshine, remember above I said how the red colour is caused by the pigment protecting the organism from the sun’s harsh rays? One option that could keep the algae away for a while longer is to move your bird bath to a shady place, out of the sun. Hopefully this won’t have a detrimental affect on your bird activity, although it could take them a short time to use the bird bath again once it has moved.

Regular Cleaning

Unfortunately, part of bird feeding is the regular clean up routine. Even on a wire dish on my feeder I see bird poos every day. If it is not cleaned up it looks awful, deters birds from visiting and spreads disease. Now put all of that into a waterborne environment and things get loads worse. Bacteria, disease and algae will be rife.

If you cannot get out every day to clean and refresh your bird bath, at least check it and use the appearance of the red stuff as a gauge to tell you how often you really should be out there. Obviously in the summer months it will run dry very quickly and you should be topping it up regularly anyway.

Using Copper Pennies In A Bird Bath

I was reading a lot about using copper in bird baths for the purpose of this blog. I found a couple of websites that suggested that using copper pennies in a bird bath does nothing and is a myth.

However, just looking through some search results led me to a number of forums and blogs that claim it actually works. These claims are from people who have actually used them and seen the results for themselves. So, let’s go with that and agree that using copper pennies, or small quantities of copper in other forms does actually prevent red algae in a bird bath.

Some things to note:

  • In the US, copper pennies should be pre 1982. This is because after that year pennies have contained much less copper. For UK pennies, or two pence pieces pre 1992 is best. Before then UK pennies contained around 97% copper.
  • Copper is toxic to fish. Whilst I doubt you are keeping fish in your bird bath, don’t be tempted to use this method in your fish pond. Also, if smaller coins are used, birds could pick them out and drop them into a nearby pond. I’m being a bit paranoid here but worth mentioning. The chap who made the video below comments that small coins were removed by birds.

How To Clean A Bird Bath

The first thing I was going to mention was that you must be sure to use a non-toxic bird bath cleaner. Following some more research for this article it appears people use all kinds of chemicals, such as bleach to clean out their bird baths. I think it goes without saying that if a bird drinks bleach it is likely to die!

The key thing is that they always spray off and cleanse a bird bath thoroughly, before putting back into use. This ensures that any chemical has been completely washed away, or at least any chemical that remains is so far diluted it will not be any risk to them or to us.

Using A Non Toxic Bird Bath Cleaner

If you like the idea of avoiding chemicals when cleaning a bird bath, the most basic of methods is to spray and scrub. Using a garden hose with a pressure setting is best, so any gunge and algae can be blasted off. The other thing you will need is a strong arm and a scouring pad of some kind. I have to say, though, this YouTube clip I found wore me out just watching it – cleaning a bird bath the hard way

If you want another tip for a more effective method of cleaning a bird bath without chemicals vinegar is my number one recommendation. You can use either white or brown vinegar but white is usually best as brown may stain certain surfaces and be counterproductive. It is readily available and way cheaper than other manufactured cleaning products. It is also better for the environment, especially if you use cider vinegar, which is likely to be organically produced. Its a winner all round!

Vinegar is great for cleaning so many things; I have used it mainly on dog wee in the house (only a couple of accidents) and not only does it clean well but leaves a more favourable smell than what was cleaned up. Vinegar can be used to clean a bird bath and will not be toxic or harmful to birds. Nor does it cause us any harm, unlike bleach or chlorine based products.

How To Clean A Bird Bath With Vinegar

Here are some simple instructions for cleaning a bird bath with vinegar:

  1. Tip out the old, contaminated water to a suitable place, maybe over plants in the summer.
  2. Scrape out anything that remains, like encrusted droppings, spilled seed and so on.
  3. Make up your vinegar solution of 1 part part vinegar to 9 parts water. This can be varied and some other guides recommend 1 part vinegar to 4 parts water. If your bird bath is quite bad, maybe go with the stronger solution.
  4. Now, using a scrubbing brush or scourer (pretty much anything you have that does the same), scrub all areas of the bird bath, especially the areas where birds perch and drink from. Get into all the nooks and crannies, making sure you cover the whole thing. If your bird bath is really bad, leave the solution to soak for a little while before coming back for a good scrub. Be sure to cover the bird bath so birds don’t come and drink the vinegar.
  5. When you are done, rinse the bird bath with clean, running water to clean away any vinegar.
  6. You should now allow the bird bath to completely dry.
  7. Finally, refill the bird bath with clean, fresh water and enjoy the birds.

Using Bleach To Clean A Bird Bath

If you aren’t bothered about going down the no-chemical route and want to clean your bird bath really effectively and easily – use bleach. In the UK most kinds of chlorine based bleach is perfectly fine; Domestos or an own brand. Most will contain a 5% – 6% chlorine solution. In the US a poopular and recommended brand is Clorox.

There is little scrubbing required for this method but a strong hose jet is best and something suitable to cover the bird table while the bleach does its thing. It is important to note that bleach can be harmful to us and can discolour clothing. Use gloves and consider eye protection.

Interestingly, bleach is not technically a cleaning product in the sense of the word. It is a very effective disinfectant, which serves a similar purpose and gets things looking nice and clean.

Until I can post my own video doing this, here is a very simple instructional video. Its as basic as it gets but it works. Copper also features in this video, which is why I included it.

The only thing with using bleach is that to get the best results, you need to leave the bird bath for a number of hours. Personally, this doesn’t bother me but many might prefer a more instant result using another method.


Red algae in a bird bath is completely normal and there is very little you can do to stop it completely. It is not harmful to birds and there are proven methods you can use to help reduce it and to keep your bird bath cleaner for longer. These include moving the bird bath to a shaded placed out of the sun and putting some copper pennies in the water. Copper if a algaecide and when put into water can help to prevent algae.

Clearly, you should be out there cleaning your bird bath regularly in any case – droppings, insects, seed all play their part in spreading disease, making a bird bath a no go zone for birds. I have shown you three methods of cleaning a bird bath – from good old fashioned scrubbing and using vinegar to using bleach. They all work but each one provided different benefits to us, our birds and the environment.

Additional Question

How do you prevent a concrete birdbath from going red? This can also be answered by following the steps above. However, the thing to remember with a concrete is that, compared to plastic or metal, it is rougher and has way more tiny holes and crevices for algae to grow in. The key will be prevention in the first place, so keep a concrete bird bath in a shaded place if possible and give it a spray off a bit more often.