The number of some Irish birds seen in the garden is in decline, but we can help them to survive by creating favourable habitats, writes FIONNUALA FALLON

I’ve spent the past few weeks counting birds. Not calling birds, French hens, turtle doves or partridges, I should add, but robins, finches, crows, tits, siskins and blackbirds as well as magpies, treecreepers, wrens and the occasional shy jay. I even, briefly, had a stab at counting the flock of whooper swans that first arrived to graze a neighbouring farmer’s field in early December, their hoarse cries and snowy white forms heralding the arrival of winter proper.

That was until I reread the instructions accompanying Birdwatch Ireland’s garden bird survey 2012/2013 form , and noted the polite request to participants to “please don’t count birds that you see outside the garden”. Oops.

Back inside Irish gardens, the results of the previous year’s Birdwatch survey reveal that despite a decline in population numbers caused by the harsh winters of 2009 and 2010, the robin remains Ireland’s most widespread garden bird, having been spotted by 98.6 per cent of the participants.

Close behind this red-breasted songster (the only Irish bird whose fluting song can be heard throughout the winter months) comes the blackbird, followed by the blue tit, the chaffinch, the great tit and the magpie.

Sadly, the same survey also reveals a decline in the numbers of other Irish garden birds, in particular four species of thrush, namely the resident mistle thrush and song thrush as well as the redwing and the fieldfare, both of which are winter migrants.

Figures for the song thrush, whose “full-hearted evensong of joy unlimited” has inspired countless poets and writers, are perhaps the most shocking. Once ranked in eighth place, it has tumbled to 18th. The results of my own rather informal garden survey of the past few weeks back up these statistics. In a garden where they were once a common sight, I have scarcely spotted a single thrush.

According to Oran O’Sullivan of Birdwatch Ireland, this decline is almost certainly the result of those two previous icy winters. “Harsh conditions in early winter ensured an early clear-out of berry resources in the countryside, and freezing ground conditions cut short a supply of invertebrates in the fields. Although some found sanctuary in gardens, many thrushes and other bird species undertook a mass westerly movement, desperate to find a food source, and many perished flying west out to sea along our Atlantic seaboard.”

There’s no doubt that last year’s dismal spring and summer further compounded the problem, resulting in a poor breeding season. Late spring frosts also severely affected potential food sources by killing off insect larvae while frost-damaged blossoms resulted in a scarcity of fruits and berries.

The good news is that gardeners can help to reverse the thrush’s decline in a variety of different ways. First and foremost, do what you can to create a favourable habitat.

A thick hedge, a few well-chosen evergreen shrubs, some fruiting or berrying trees, a not-too-well-tended lawn, a wall covered with creepers – each and every one of these will offer shelter or food, or both.

Pockets of dense planting will also offer nesting cover for the song thrush, who likes to position its nest in a well-hidden spot, while the mistle thrush (its larger, pot-bellied cousin) is less secretive and will happily nest in the crook of a branch.

The latter is particularly partial to holly and mistletoe berries but all thrushes rely on a range of fruit and berries as a vital source of food in autumn and winter.

Our native mountain ash (Sorbus aucuparia), for example, is not only a handsome specimen tree but its clusters of blood-red berries are irresistible to these birds. The scarlet berries of the evergreen yew (Taxus baccata) are another magnet, as are sloes, elderberries and those of ivy, berberis, cotoneaster, pyracantha and the native guelder rose, Viburnum opulus. The bigger species of thrush (the fieldfare and the mistle) will also eat rosehips.

Ripe or windfallen fruit is another big draw, while even a shop-bought apple speared onto a sharp branch will be appreciated on a frosty winter’s day.

Fruit and berries aside, thrushes also eat earthworms and insects, both of which are an important source of protein. Lawns are especially rich hunting grounds for earthworms ,while a garden rich in a variety of different habitats that maximise its natural ecosystem will be a haven for insect life.

Last but not least, these speckle-breasted birds are also the gardener’s friend in that they’re partial to eating snails. Be aware that poisonous pellets, whose active ingredient is methiocarb or metaldehyde, are one of the factors suggested to have contributed to these birds’ decline. Food for thought as we begin another gardening year.

For more details of the Birdwatch Garden Bird Survey, see birdwatchireland.ie