In the Glens of Antrim I watched a rook taking bread that had been put out and, having eaten its fill, burying it in pieces over an area of a field nearby. Is this like squirrels hoarding food for a rainy day, or is something else going on?
Brian Scott, Antrim
Rooks normally feed in flocks so that they can fully exploit a food source such as a newly ploughed field. They make caches of acorns, taking them from the oak trees through October and hiding them in the fields. They hide earthworms too - but not for long.
A wagtail has been hopping up and down on the wing mirrors of our car as if trying to get into them. Even though we turned the mirrors inwards to discourage him, the poor thing is still at it.
S Clarke, Killala, Co Mayo
A blue tit has been flying at my window and knocking itself beak and body against the glass. What is the intention of this crazy bird and how can I stop it?
Niamh Neumann, Newcastle, Co Wicklow
Both of these birds think that their reflection in the window is an interloper into their territory and they are trying to chase it away. In the case of the window some way of breaking the reflection on the glass by throwing a shadow on it might help; hanging a cut-out of a hawk or falcon in the window could also work.
With reference to Helen Lucy Burke's query as to why wagtails wag their tails, there is a possible Darwinian explanation. Wagtails, especially grey wagtails, usually live beside fast-flowing streams. With such a background, a bird which is bobbing up and down is less likely to be seen by a predator than a bird that is standing still. The fact that two other unrelated species, the dipper and the common sandpiper, also live beside fast-flowing streams and have evolved the same bobbing behaviour supports this theory.
Kevin Collins, Clonmel, Co Tipperary