Otago people are being asked to keep an eye out for rooks.
Otago Regional Council staff are carrying out rook control until November. They are asking people to look out for the black birds, their rookeries and nesting sites.
There used to be thousands of nesting rooks in Otago, but their numbers have been drastically reduced through control programmes.
Rooks (Corvus frugilegus) are part of the crow and raven family, larger than magpies and totally black. The black feathers often show a purple or bluish-purple sheen in bright light.
They were introduced to New Zealand from Europe by early settlers to control insects, but can cause significant damage to crops and pasture.
Council regional services director Jeff Donaldson said about 100 nesting birds remained in Otago. These have been reported in North Otago near Duntroon and Tokarahi, as well as in the Maniototo, Middlemarch, Clarks Junction and Clydevale.
''Our best asset is the eyes and ears of all those on the ground,'' Mr Donaldson said.
''Without local information, it's just like searching for a needle in a haystack, trying to find the remaining small populations.''
Anyone who sees a rook should not shoot at it or scare it, he said. If disturbed, rooks could scatter to form new rookeries.
''Anyone sighting a rook or rookery just needs to give us a call and our pest eradication staff will come and deal with them as a free public service.''
Phone Malcolm Allan on 027-278-8498, the council on freephone 0800-474-082 or email: info@orc.govt.nz