Church members are hoping that a pair of peregrine falcons will not nest on St Wulfram’s and stop work on the spire.
The falcons have been seen flying near the church and it is thought they may try to nest in the tower as they have for some years.
If the protected birds nest on the church, then work on the spire will have to stop.
It had already been hoped that £600,000 of repairs to the spire would be finished by now, but delays have meant it is not due to be finished until March.
Fr Stuart Cradduck, rector of St Wulfram’s, said efforts are being made to prevent the birds from landing and nesting on the tower.
He said: “We are seeking professional advice and we have netted off the bottom of the parapet. We are looking to see if we need a bird scarer up there.
“If they did start nesting then everything would have to stop until they flew away. That’s the nightmare.
“But I think we will be ok. They will not start nesting until about March and hopefully by then the scaffolding will be ready to come down.”
Fr Stuart says that the planned rededication service on March 17 will go ahead whatever the situation with the spire.
Once the work is finished, the church hopes to hold spire tours when people can pay to climb the scaffolding to the top of the spire.
A few weeks ago the church announced it needed to find an extra £42,000 because of the delays. It costs about £2,000 per week to keep the scaffolding up.
The falcon has special protection status under the Wildlife Act and their nests are protected.