A bird species known for their unusual migration patterns have now been declared extinct after research found these animals have not been seen since 1995.

The slender-billed curlew are a bird species which is easily recognisable thanks to its short and very slender bill with pear-shaped black markings on its flanks.

Analysis of the species conservation status was recently published by scientists from the RSPB, BirdLife International, Naturalis Biodiversity Centre in the Netherlands and Natural History Museum. They found the last irrefutable sighting of the bird in Morocco, Africa back in February 1995 finally concluding its global extinction.

These birds are a migratory shorebird that were originally bred in western Siberia and migrated to the Mediterranean in winter.

This bird species extinction is now the first mainland European, North African and West Asian bird to go extinct in half a millennium.

This species of wading bird was last officially seen in 1995 despite the occasional unsubstantiated reports since then.

Scientists and researchers have combed through available data on slender-billed curlews concluding in its fatality.

Dr Alex Bond, who worked on the research involved in tracing the slender-billed curlew and is the senior curator and head of Birds at the Natural History Museum, explained how the bird simply "stopped returning".

"When the slender-billed curlew stopped returning to their main wintering site at Merja Zerga, Morocco, there was quite a lot of effort put in to try and locate them on breeding grounds.

"Several expeditions, hundreds of thousands of square kilometres searched. And all this has turned up, unfortunately, is nothing."

Slender-billed curlew's were known to scientists for their unusual migratory route clearly not fans of the cold weather as they were often seen flying south-west away from the region of Khazakstan and southern Russia.

The birds would pass through the Danube Delta, across the Balkans towards southern Italy with many others landing up in northern Morocco where they would ride out the winter.

Sadly researchers findings now suggest there is a 99.6% chance that the bird no longer exists.

Their extinction is likely down to two reasons explains Dr Bond with hunting during their annual migration over Europe being one.

Dr Bond explained that these birds were commonly found for sale in many markets across southern Europe, particularly in Italy.

The rapid agricultural development in the Soviet Union also likely contributed to the bird's demise as during the mid twentieth century the conversion of the grasslands of central Asia destroyed many of the bird's remaining breeding grounds.

Principal policy officer for the RSPB, Nicola Crockford said: "This is one of the most fundamentally devastating stories to come out of nature conservation in a century and gets to the very heart of why the RSPB and BirdLife Partnership are doing what we do; that is, ultimately, to prevent extinction of species."

Despite the researchers irrefutable conclusion of the species extinction, the International Union for Conservation of Nature (IUCN) which lists animals on its red list when extinct has yet to add the slender-billed curlew.

"Declaring a species extinct is not something that is done lightly and the IUCN who make the ultimate decision on extinction for the red list of threatened species need full details of the status of a species before doing so," said Graeme Buchanan, head of international conservation science with the RSPB.