Corncrakes are the opposite of the ideal Victorian children. They are heard and not seen.
Until about forty years ago they could be heard calling in many fields in the Hebrides, but changes in agricultural methods have affected them severely. Nowadays they are confined to just a few islands. The main breeding population is on Tiree, but in 2008 there were fifty calling birds on Iona and 7-10 on the neighbouring Ross of Mull.
The rasping 'crek-crek' call of the male attracting a mate is unmistakeable, but it is very much more difficult to determine where it is coming from. If you try to creep up, the bird stops calling and slips away.
© Tim Dawson
Corncrakes migrate, arriving from somewhere in Africa in April or May.
Their preferred habitat is amongst vegetation that has died down over winter and re-grown. June is the main calling month. Having attracted a female, a male may move on and call from another site, leaving the female to lay her eggs. Chicks are hatched and mobile by mid-July. It is at this time that the birds are most vulnerable, as with the chicks unfledged and the adults moulting they cannot escape by flying.
Modern hay-cutting methods herd the birds into a confined area in the middle of the field, and either they break cover when they are easy prey to all predators, or they remain, only to be mown down. Some farmers have now adopted 'corncrake-friendly' cutting methods. They leave cutting until August, and start at the centre of the field and work out. The birds can then more easily reach cover.
In September the corncrakes depart for Africa again. Their destination is not well understood, and very few birds have ever been reported in Africa.
Because their life-span is short, a population can be wiped out by just a couple of poor breeding seasons
Read more about other birds on Mull (PDF)