Jackdaws

 Jackdaws nest in rock crevices and small caves but also house chimneys where they drop twigs down the pot so that they lodge and form the base of a nest. In modern times many chimneys are connected to enclosed stoves via a flue pipe and birds looking for a nest site are apt to fall down and become trapped in the stove.
This bird was fortunate in that I was able to open the stove and release it apparently unharmed but many are not so lucky.