While all of the factors that cause house sparrow decline have not yet been determined, research has shown that there are many things that you can do to help conserve and protect them. Below are some key ways you can contribute based on findings from the Glasgow House Sparrow Project research team as well as many scientists around the UK.
Hedges
If you have a garden or manage an urban green space, consider how your hedges are maintained. Hedges and any other greenery that provides cover for the birds, such as bushes, shrubs, and small to medium trees are key for sparrow survival. Our analysis has shown that they may be one of the most important factors to house sparrow colony success: gardens that had full, dense hedges were 85% more likely to have sparrows in them than gardens that lacked green cover.
One of the key elements determining if house sparrows use hedges is their structure. Many garden hedges are now kept heavily trimmed, creating a tight frame that can act like a wall when the birds flee potential predators. The hedges that were found to be used most often by the sparrows had little to no maintenance, which gave them an open, loose composition. You can test this for yourself by sticking your hand into a hedge: it is difficult to pass your hand into heavily trimmed shrubs, but this same motion is very easily done into ones that are left a little wilder. This same principle applies to birds quickly flying into cover when evading predators.
There is also evidence that birds prefer native species; for Scotland, this will include species such as hawthorn, blackthorn, alder, wild privet, and wild cherry. Planting these species provides valuable cover and food (in the form of insects and berries) for house sparrows and other garden wildlife while making sure that native plant species are also preserved.
Feeders
Providing feeders is a good way to help the birds both during the busy spring and summer breeding season and the resource-limited autumn and winter months. House sparrows have long been associated with humans and have adapted readily to human-provided food sources.
House sparrows will readily eat most seed mixes, but can also be attracted with peanuts and sunflower seeds. Avoid mixes that are largely comprised of wheat or cereals, as the sparrows largely toss these on the ground. During the busy breeding season, when the birds are actively rearing their young, offering mealworms can help ensure a steady supply of the high-protein invertebrates that the growing chicks need. To keep from spreading disease, make sure you clean feeders regularly, about twice a year.
One important factor documented in the data was that the house sparrows tended to stay within 1 metre of hedges. This allows the birds to quickly dart into cover when there was a potential threat nearby. Feeders should be placed within this safety zone where possible to attract the most birds.
Meadow plots
Another way to provide food for the house sparrows is by planting a wildflower plot in your green space. Wildflowers are an excellent year-round source of food for the birds: in the spring and summer, they attract invertebrates that can be fed to the hungry chicks and in the autumn and winter, they provide valuable seeds to sustain the birds through more resource-scarce times.
Making sure that there is a wide mix of species will increase the species richness and therefore the food availability for the sparrows. Our research found that the sparrows preferred taller vegetation, so letting this section of your garden or green space go a little wilder would also help attract the birds. Just be sure not to let your patch become overgrown; if the flowers are choked out, the sparrows don’t benefit.
Nest boxes
Providing opportunities for nesting birds is crucial to sustaining populations. With modernised buildings, the cracks and crevices previously used for nesting have become more scarce, which is thought to have contributed to house sparrow decline.
House sparrows—being the gregarious birds that they are—are social nesters. A single nest box is unlikely to attract any sparrows. Instead, set up at least three boxes for your colony. Nest boxes should be at least 3 metres from the ground and protected from full sun or high winds. Position your boxes under the overhang of your roof or attach them to a drain pipe using luggage straps as seen to the left.
Of course, the wrong design will attract the wrong occupant: make sure it is an enclosed box with a hole that is approximately 32 mm in diameter. Keep in mind that house sparrows can be quite dominant and, while they are colonial nesters, they may show aggressive behaviour to other species: keep boxes for other species separated from the sparrows.
You can readily buy pre-made nest boxes for house sparrows, or try your hand at making one yourself.
House sparrow-friendly gardening
All of the elements listed above contribute to creating a house sparrow-friendly garden. If your garden or local green space looks like it needs quite a bit of care and clean-up, don’t despair—you may be closer than you think to a garden bird haven! While it may seem like the easiest place to start is with a blank slate, green spaces that are already a bit wilder have a home-grown advantage: they may already be attracting wildlife.
Picking up litter and doing small amounts of management in cluttered areas can quickly transform a green space. Leave small brush piles, which will attract insects and the garden birds that rely on them for food. Leave any wildflowers that have sprung up or add a patch. Work with the features that are already a part of the garden instead of clearing them out and you are on your way to creating a sparrow-friendly garden that will attract a diverse array of wildlife.
Volunteering
Another way to become actively involved with the house sparrows is to volunteer for the Glasgow House Sparrow Project. As a volunteer, you can conduct surveys, assist with public engagement events, write guest blog posts, and attend an annual meeting to chat with the researchers. We would particularly welcome any sparrow sightings through the Report Sightings section on the project website. And be sure to connect with us on social media via Twitter @GlasgowSparrows.
Find out more about the Glasgow House Sparrow Project by following along on our project blog!