Peregrine nest boxes and gravel depth

At this time of year, we regularly see the same questions raised about our Peregrine nest boxes. This year has been no exception.

Whilst we accept that these questions/comments/suggestions are generally well-intentioned and we welcome positive dialogue on our projects, we ask that people bear in mind that our conservation officers all have many years of experience in using artificial nest boxes in urban locations.

In many cases nest box design, placing and access to them is heavily influenced by where they are. In the case of Norwich cathedral, for instance, the nest box design was carefully considered to fit within regulations dictated by the Cathedral Fabric Committee. Access is very difficult and has to be carefully scheduled.

Our nest boxes give these wild birds an option for nesting, they are free to choose elsewhere if they wish and they could certainly attempt to nest elsewhere on the building. The boxes are chosen because the conditions are right for the birds.

It is well documented that wild Peregrines nest on grassy or earthen cliff ledges or quarry rock faces, occasionally they will nest on bare rock or even bare metal pylons. The nests are, at best, slight scrapes.

The gravel depth at the Norwich nest box is monitored closely. The nest box has a lip at the front, preventing eggs or chicks from falling out. Increasing the gravel depth, especially as not necessary, will increase the danger of eggs or chicks being knocked off.

This nest box has been extremely successful in previous years although we recognise that in the last two years there has only been one chick successfully fledged. This, however, has resulted entirely due to the arrival of an inexperienced young female who took over the nest site in an aggressive way, a sad but not uncommon occurrence in wild birds. In no way has the structure or dimensions of the nest box, or the depth of the gravel, affected this outcome.