An iconic Scottish seabird, which was driven to extinction on Hebridean Island by rats, has returned to nest in what is proving to be a bumper year for several internationally important species.

The discovery that manx shearwater has returned to nest comes as studies demonstrate several endangered seabirds are returning after years of decline, with some having their most successful breeding seasons for a decade.

It must be noted that Scotland has about 5 percent of the European Union's (EU) breeding population of seabirds.

Moreover, the National Trust for Scotland (NTS) provides nesting sites for nearly a fifth of them at properties in Iona, St Abbs, St Kilda, Fair Isle, Mingulay, Canna, Unst and Staffa.

The numbers of threatened species such as shags, kittiwakes, guillemots and puffins have actually increased in 2014 at several colonies around Scotland, according to the latest NTS research.

There are steep declines among several seabirds in recent years. Black-legged kittiwake populations have declined by almost 90 percent since 2002 at one location in St Kilda, which is the world heritage site situated 41 miles west of the Outer Hebrides.

On the other hand, the sea parrot has also experienced a long-term drop in breeding success, although they are doing better on St Kilda this year.

Latest counts in Hebrides have demonstrated a 46 percent rise in the number of kittiwakes nesting at Mingulay since 2013. The birds have also enjoyed greater breeding success this year when compared with previous years.

Moreover, species such as European shags, common guillemots and razorbills have also demonstrated significant increases in both breeding success and numbers.