A carrier pigeon. [File photo/Sina Weibo]

Keepers have still found no trace of about 3,000 carrier pigeons after they took off in a flying contest held last Friday, Ecns.cn reported.

Altogether, more than 3,000 birds joined the event. They were scheduled to fly 500km from North China's Shanxi province to neighboring Shaanxi. However, none of them reached the destination 24 hours after release.

Organizers say it would normally take the pigeons 7 hours to fly the distance. They added that small earthquakes were detected on their flight path, which could alter local magnetic fields and affect navigation. The claim was backed by statistics from the local earthquake monitoring center.

So far, organizers have retrieved several hundred pigeons, though most are still missing in action.