Parrots start disappearing around the time of the Hajj
Smuggling is particularly intense at the time of the Muslim pilgrimage to Mecca, known as the Hajj.
African grey parrots are not a globally threatened species.
But under the Convention on International Trade in
Endangered Species (CITES) only limited trade under strict licensing is
Thousands of parrots are smuggled each year from the forests straddling the border between Cameroon and Nigeria.
Conservationists say that traders buy the birds for
less than $10 (around £7) - and then sell them in Asia and the Middle
East for $5,000 each.
Saudi Arabia has the highest demand - with a huge increase in smuggling just before the Hajj.
Grey parrots have become a status symbol, because of their ability to mimic speech.
Last month, in the weeks running up to the Hajj - over
100 birds were found stuffed into crates at Calabar Airport, in
Nigeria's far south-east.
A local wildlife organisation described them as "extremely battered".
The authorities were informed several days later - but by then the parrots had gone.
Even if officials had been told in time, there is no guarantee anything would have been done.
Paddy Ezeala of the Nigerian Conservation Foundation
told the BBC that few officials are aware of the law. Those who are,
can often be bribed - and as a result the trade in the birds has grown.
African greys are not classified as an endangered species - but they can only be traded under strict conditions.
Mr Ezeala estimated that between 5,000 and 10,000 of the
birds are illegally captured in the region and shipped out through
Nigeria each year.