AN UNUSUAL 'tchip, tchip' call floated across the air from the top of a hawthorn just a short distance from the Devonvale Hall at Tillicoultry.

I quickly realised these calls were coming from tree sparrows, a close cousin of more familiar house sparrow, but not nearly as common.

Tree sparrows look similar to house sparrows but are slightly smaller and can be identified by their brown caps and little black 'ear' marks on the side of the head.

Tree sparrows are sociable birds and like to be with their own kind. Whilst relatively scarce in Clackmannanshire, they are very site faithful, and there are several locations I know where I am guaranteed to see them.

In the Wee County, they seem to prefer areas of arable or mixed farmland, especially where there are hedgerows.

A short distance further along the Devon Way walkway, a white shimmering caught my eye. It was a blackthorn bush slowly emerging into full bloom, with each flower revealing five intricate white petals.

Shortly, the whole plant will burst into a white-frosted magnificence, making it one of the most stunning sights of spring.

The unusual thing about the blackthorn is that it flowers first, with the leaves following later. Even when the weather turns freezing the flowers will still blossom, with a cold spring traditionally being known as a 'blackthorn winter'.

The 19th century poet Christina Rossetti brought into sharp focus the striking beauty of the blackthorn as it was about to blossom, or 'blow', with the lines: A cold wind stirs the blackthorn, To burgeon and to blow, Besprinkling half-green hedges, With flakes and sprays of snow.

The white blossom is a magnet for early emerging bumblebees and other insects, and once the leaves are set, they are a principal food for many different types of moth larvae.

The blackthorn is important to wildlife in other ways.

The impenetrable tangle of twigs and thorns makes the shrub a great favourite of birds as a safe place to build their nests.

Birds are also attracted by the many caterpillars found upon their leaves.

The blackthorn is undoubtedly best known for its bitter tasting fruits we all know most familiarly as sloes, and which are used for making wine, jams, and of course for flavouring gin.

Sloes are very high in vitamin C and have been foraged by man since the earliest of times.

Sloes are certainly an acquired taste, and I was very much taken by this verdict on the dubiety of their flavour as experienced by William Cobbett in 1825.

He wrote: "This pulp, which I have eaten many times as a boy until my tongue clove to the roof of my mouth and my lips were pretty much glued together, is astringent beyond the powers of alum".