Changing the way we support our Garden Birds

Feeding garden birds brings a lot of joy to thousands of households nationwide, and we recognise that people want to do what they can to support Ireland’s birds. However, new research has emerged which suggests that changing the way we feed birds (natural vs supplemental) and shifting the seasonal frequency with which we put out feeders, will serve to benefit our garden birds more by reducing the transmission of diseases, such as trichomonosis.

The spread of disease

Trichomonosis is a disease that primarily affects finches, but can occur in other species, and has a high fatality rate. It is caused by the parasite Trichomonas gallinae, which is spread through direct contact with infected birds, food, regurgitation, droppings, and shared water sources.

What is the data saying?

Following recent scientific research conducted by the Royal Society for the Protection of Birds (RSPB) and the British Trust for Ornithology (BTO), BirdWatch Ireland has investigated Irish data and trends. Data from the Irish Garden Bird Survey has shown >30% decrease in garden visits by Greenfinch, compared to 10 years ago (Figure 1). Additionally, there was a 13% decline in gardens visited by Chaffinch and an 11% decline in Goldfinch visits last winter compared to 10 years ago.

Figure 1: Percentage of gardens that have recorded Greenfinch during the Irish Garden Bird Survey (winter 1994/95 to 2024/25)

Data collected through the Countryside Bird Survey (CBS) have also shown dramatic declines in breeding Greenfinch since 2006 (Figure 2). There are many pressures impacting wild birds but we are seeing a >50% decline in our breeding and wintering Greenfinch in the last 20 years, since the disease first emerged in 2005. Other finch species are affected too, with CBS records of breeding Chaffinch and Bullfinch on the downward trend since 2018, and there is evidence to show that Siskin, Redpoll and Linnet are also susceptible to the disease.

Figure 2: Breeding Greenfinch trend from the Countryside Bird Survey

The new guidance on feeding garden birds

Research (linked below) shows that the disease is more prevalent in summer and early autumn. The spread of trichomonosis at this time is of particular concern due to the potential of infected parents passing food to their young, which can devastate an entire brood. BirdWatch Ireland therefore agrees with the latest scientific advice to reduce supplemental feeding of birds through garden feeders.

We are strongly urging people to move away from using bird feeders from May 1st to October 31st to reduce the spread of the disease and allow the affected populations to recover.

Birds gain the greatest benefit from garden feeders during winter, when natural food sources like seeds, berries, and insects are scarce. In contrast, summer and autumn provide abundant natural food, allowing birds to feed themselves and their young without supplementary feeding. Encouraging birds to rely on these natural sources helps prevent large gatherings at feeders, which in turn lowers the risk of disease transmission.

Supporting your garden birds: best practice

We would encourage you to practice wildlife friendly gardening and to provide suitable plants to support your garden birds and reduce the transmission of disease. Make your garden as species rich as possible, with native trees and shrubbery, which will provide natural food sources and encourage natural foraging behaviour. The best trees are the ones that produce berries or seeds, as these will provide natural foods for them in autumn and winter, nesting space in summer, as well as shelter and shade all year round.

Hawthorn, blackthorn, elder, holly, brambles and gorse will all provide food and shelter. Grasses and wildflowers including thistles and dandelions that have gone to seed are also valuable natural sources of food for our wild birds so reduced mowing and leaving parts of the garden to nature, can all help our garden birds. We have plenty of publications detailing wildlife friendly gardening tips (linked below) but we will continue to provide seasonal advice to guide you as we collectively make this transition. You can also read about campaigns such as No Mow May, Let it Bloom June and Help them Fly July here.

What about feeding in winter?

If you want to continue to support your garden birds in winter, when natural food sources are at their lowest, please do so. We believe that the connection to nature gained by providing feeders, and the subsequent garden birdwatching, is also a vital role in supporting Ireland’s birds. However, we would strongly urge you to follow a strict hygiene protocol. A few simple steps could go a long way in the fight against this disease:

Clean your feeders weekly. Clear out any build-up of food and disinfect thoroughly.
Only half-fill your feeder. This will reduce any build-up of uneaten food and make regular cleaning easier.
Do not use flat-surface feeders. These surfaces allow a build-up of potentially infected food, droppings and regurgitated food brought up by sick birds.
Change water in bird baths daily.
Move your feeders to different spots in the garden regularly. This reduces the buildup of fallen food on the ground.

Different foods to feed your garden birds

If you want to attract a diverse mix of bird species, then provide a wide variety of different foods to cater for every taste! Various considerations come in to play, not least the financial costs, so here’s some further information on the different foods you might be thinking of providing for your garden birds:

Peanuts

One of the most popular bird foods, and for good reason. They have a high calorie content (behind only sunflower hearts), are high in protein and they have no shell that birds need to wrestle off. Perfect if you want to avoid spillage and waste too. Be sure to hang them in an appropriate mesh feeder, and don’t use plastic netting bags. Take care to ensure no mouldy or shrivelled peanuts are in your feeders as these can produce aflatoxins which can kill birds. To avoid this, store them in a dry area and half-fill your peanut feeders at a time, allowing them to empty before refilling. Peanuts are popular with probably the largest range of species, including all of the tits and finches, house sparrows, and more!

Buy peanuts & feeders

Sunflower seeds

These are a good ‘standard’ food to provide if you want to cater for a variety of bird species. Sunflower seeds come in different forms – with striped shell, black shell or no shell (‘hearts’). Striped shelled sunflower seeds have a tough outer shell that’s difficult for birds to remove and they have a lower calorie content than the other varieties. Black sunflower seeds have higher oil and calorie content and a thinner shell too. Sunflower hearts are the best of the lot though as they have more oils and calories than the others, and no shell – so the birds waste no energy when eating them. They’re a bit more expensive as a result, but worth the money. Sunflower seeds should be provided in a hanging seed feeder or scattered on a flat surface.

Buy sunflower seeds & feeders

Mixed seeds

There’s a lot of different mixed seed varieties on the market. Cheaper ones tend to include a high proportion of cereal grains that are popular with sparrows and pigeons but not much else. If you want to cater for these species (and they deserve food too!) then you’re ok, but if possible go for the mixes with better quality content as these are ultimately better value for money. There’s a great range of ‘high energy’ mixes available these days, including ones with high proportions of sunflower seeds and with added mealworms and suet pellets that are all good and will be eaten by a good variety of species.

Buy mixed seeds & feeders

Nyger seed

Nyjer/Nyger is a relatively new addition to the bird food market. The seeds are very fine, so are much loved by the finches that traditionally enjoy thistle seeds – most notably Goldfinches, but also Siskin and Redpoll. Nyjer requires a specialised bird feeder with smaller holes as it can be quite messy. It’s one of the more expensive foods on the market too, but is still very popular and maybe worth providing in smaller amounts than other foods (peanuts, sunflower hearts).

Buy nyger seed & feeders

Fat/Suet products

There’s a big range of fat and suet products on the market, with different nutrients and ingredients added. Be wary of very cheap supermarket options that tend to be very poor in any sort of nutrients and can be quite tough for birds to eat. Don’t be afraid to make your own fatballs with beef dripping or suet, and add ingredients such as seeds, grated cheese, raisins and sultanas (see link below). Avoid hanging fatballs in the plastic netting that they sometimes come in – these are very dangerous for birds! Be sure to buy a special fatball/suet-block feeder or cage, and if your fatballs/suet-blocks don’t fit in this then break them up a bit! Don’t provide these types of food for the late spring and summer – save them for the colder months!

Buy fatballs, suet-blocks, pellets & feeders

Make your own fatballs at home

Mealworms

These are expensive, but high in protein and are loved by Robins, Dunnocks and other species that prefer to eat insects above all else. You can add them in with the seeds in your feeder if you want or scatter them on a bird table or on the ground. This is a good food to provide in the spring and summer in particular, when you should stop feeding fatballs and suet blocks.

Buy mealworms & feeders

Fruit

Thrush species, including Blackbird, will enjoy chopped apples, pears, figs, grapes, currents, raisins, sultanas etc. Blackcaps famously enjoy halved apples stuck onto a tree branch or other spike. Cut up any larger fruits into smaller pieces so that they can be eaten with ease. As with everything, never put out anything mouldy for the birds!

Water

Water is often forgotten, but it’s hugely important for birds to drink and wash themselves in. During cold weather, other water sources in the countryside might get frozen over, so providing water in your garden is extra important. Be sure to provide it in a shallow dish, or if it’s deep bowl put a rock in it that smaller birds can perch on – they want to stand in shallow water, not completely submerge themselves!

Irish Garden Bird Survey

Ireland’s biggest bird survey is open to everyone and a great way to learn about the birds in your garden. Taking part is easy and provides us with really important data on how our garden bird populations are doing from year to year.

Get involved in the survey this winter