We have a problem with squirrels in our garden. What can we do to keep them at bay?

Q: We have a problem with grey squirrels in our city garden. They are digging in the beds and causing damage to some of the plants. Any tips on how to keep them at bay? RL, Blackrock, Dublin
A: As charming as their arboreal acrobatics might be to watch, grey squirrels can be a real problem in Irish gardens, stripping bark from broad-leaf trees, raiding birds’ nests, burrowing into lawns and digging up flower bulbs. They also feed on seeds, nuts, fruits, tender shoots and flower buds and act as a vector for diseases such as squirrel pox virus which can kill the smaller native red squirrel in a matter of weeks. They are also known to sometimes overwinter in the attics of houses where they can cause considerable damage by chewing through wires and pipework and ripping up insulation as well as contaminating water tanks. Classed as an invasive species, they were first introduced into Ireland in 1911.
Thankfully the spread of their natural predator the pine marten in recent years has acted as a curb on numbers. But in urban areas where the pine marten hasn’t gained much of a foothold, grey squirrels are still common.
How to best manage them? I know of one Dublin gardener who tried trapping them in a baited cage before releasing them into the wild. But this is not recommended, not least because they breed so prolifically that it would barely put a dent in their numbers but also because it could potentially threaten red squirrel populations.
Bird feeders are an obvious draw, so make sure to use squirrel-proof models that prevent them from easily raiding them for food. Recently planted flower bulbs are another, for which reason seasoned gardeners often like to plant theirs under a protective layer of fine mesh chicken wire concealed beneath the surface of the soil of compost. Alternatively, they can be planted into an aquatic basket (the kind used for pond plants) covered with a layer of chicken wire and then planted into the ground.
It’s also a good idea to regularly check your home for any small gaps in the eaves and/or soffit boards that could allow them entry, especially at this time of year when they are searching for a sheltered place in which to overwinter. These should be blocked up with a fine-gauge wire mesh (16 gauge, no more than 25mm size).
But even with these measures, I’m afraid that they are likely to continue to be a problem.