The ubiquitous sparrow

House sparrows are one of our most familiar garden birds. Year after year, they rank highly in the RSPB’s Big Garden Birdwatch, taking the number one spot in all but the most rural of regions.

The big sparrow slide

For some time now, it’s been clear that all is not well with our sparrows. Although still numerous, their overall population has fallen sharply, with a shocking 90% decline in London, meaning they are now on the red list, the highest level of conservation concern.

Worryingly, scientists aren’t sure why, but the RSPB has been involved in several long-running studies to find out. One project in Leicester found that sparrow chicks were suffering due to a lack of invertebrates, prompting a large-scale feeding experiment in London. This suggested that providing supplementary food helps support local house sparrows.

A team of researchers from the ZSL Institute of Zoology, in collaboration with the RSPB, also discovered that 74% of London’s house sparrows carry avian malaria, possibly influenced by our warming climate. It’s still not clear what impact this could have.

RSPB Scotland, meanwhile, worked with the University of Glasgow to look at the impacts that changing habitats have on sparrows, with teams of volunteers helping to count the birds and note what type of gardens they prefer.

A house sparrow

Sparrow studies

The cause of the sparrows’ decline is unlikely to be just one thing. Like much of our wildlife, sparrows will have seen an impact from wider environmental and climate issues like changes to farming and pollution. Some of the decline could also be down to the things we do to our houses and gardens.

Our houses are generally better built these days, meaning there are fewer sparrow-shaped holes around for nesting in. We tightly trim our hedges or replace them with fences, further reducing the places that sparrows can nest. We also keep our grass well cut and pull out weeds, so there’s fewer insects and seeds available for birds like sparrows to eat.

A nest box

How are they still number one?

Sparrows are still a common bird, so despite the dramatic declines, we’re still seeing them at our bird feeders. Their familiarity with people, and their habit of living in our gardens, means that any sparrows in an area will naturally drift towards our offer of free food. People who feed their birds may also be more likely to have a wildlife-friendly garden, offering lots of things that the sparrows need to survive, like good nesting sites and water for them to drink.

There are also signs that sparrow numbers may have stabilised, albeit at a low level. And the most recent Big Garden Birdwatch suggested that sparrow sightings have grown by 10% in the last 10 years. This could be because people are making their gardens more wildlife friendly but again, scientists aren’t sure.

Two house sparrows at a feeder

Become a sparrow champion!

Whatever the cause of their decline, research has shown what sparrows need to give them the best chance of survival. If you have a garden, you really can make a difference to the fortunes of your local house sparrows and become a sparrow champion by:

  • Taking the #hedgepledge to provide nesting space and a place to hide.
  • Encouraging more insects by letting your grass grow or planting wildflowers.
  • Putting up a nest box. Sparrows like to nest in colonies, so consider putting several side by side.
  • If you don’t have a garden, look around your local area or park and see if there’s any space for sparrows. You could write to your local council and urge them not to cut grassy verges or ask your local housing association if they would put up some nest boxes.
Poppies and cornflowers