The ups and downs of the mobile nesting site

SIR – I am a volunteer lock-keeper and have seen grey wagtails nest in the lock gates (Letters, July 23). They seem unfazed by the gates constantly opening and closing or by the vibration when they shut together.

Mike Day

Waverton, Cheshire

SIR – We have an 80mm bore cannon in our garden. In the last few years blue tits, coal tits and great tits have nested in it. Last year white-tailed bumble bees took up residence.

When our first lodgers arrived we had a cat so we put a fence round the cannon. In very hot weather we put wet towels on the cannon to keep it cool.

Rona Taylor

Stopping here: a thrush raising its family in an amber traffic light in central Leeds