We all need a place to call home. Somewhere where we feel safe and protected. Where we can chatter away in peace and security. Sparrows are no exception!
House sparrows have declined markedly since the 1970s, although numbers have increased slightly in the past decade. There are a number of possible reasons (See Link 1), but one of them is loss of suitable nesting sites. According to the BTO, House sparrows need “thick cover to escape from predators, rest, roost and socialise.” (Link 2). Hedges are good for all of these activities, but they need to be the right sort of hedge.
How to tell whether a hedge is good for sparrows? Just stop and listen! Sparrow-friendly hedges are alive with the sounds of chattering sparrows. You might not see the birds, but you should be able to hear them chirping away inside.
The hedges need to be thick enough to provide cover and protection, but not too thick, as that will stop the birds from being able to enter and access it. The rather nondescript hedge (above) in the middle of a car park in Scarborough is thick with sparrows. There are also plenty of trees nearby into which they can take refuge as well. There must also be plenty of sources of food nearby.
House sparrows probably arrived in Britain about the time of the Romans, and they remain closely associated with Man. They fit in well in urban settings, but they have certain needs. Allotments and gardens – particularly ones that are not too heavily manicured – are great for sparrows, which tend to do well in slightly run-down areas! Don’t be over-tidy says the BTO!
Sparrows normal nest sites are holes in buildings but if these are not available they regularly build untidy detached nests within ivy (see below). If people strip away such vegetation from their houses, the poor sparrows will have to find nest sites else where.
Sparrows need food, so allowing your lawn to grow up to between 3–6 cm in height during spring and summer
will allow low-growing plants such as dandelions and plantains to go to seed (Link 2).
What is a sparrow-unfriendly hedge? One that is too dense, or too prickly without any internal spaces, like the following examples (below).
There are still nearly 7 million pairs of House sparrows in the UK, so they are not endangered. But they bring such pleasure and delight, and they are so beautiful when you look closely at their plumage, that I think we need to do all that we can to share our spaces with these little passerines!
Links
Ray Cannon's nature notes 
Fortunately, there is a large population of house sparrows in our garden—thanks to a 65 yd long and 9 ft high sparrow-friendly hedge, which is also home of many blackbirds as well as numerous insects and snails.