August 27, 1792
A fern-owl this evening showed-off in a very unusual, & entertaining manner, by hawking round, & round the circumference of my great spreading oak for twenty times following, keeping mostly close to the grass but occasionally glancing up amidst the boughs of the tree. This amusing bird was then in pursuit of a brood of some particular phalaena belonging to the oak, of which there are several sorts; & exhibited on the occasion a command of wing superior, I think, to that of the swallow itself. Fern-owls have attachment to oaks, no doubt on account of food: for the next evening we saw one again several times among the boughs of the same tree; but it did not skim round it’s stem over the grass, as on the evening before. In May these birds find the Scarabaeus melolontha on the oak; & the Scarabaeus solstitialis at Midsummer. These peculiar birds can only be watched & observed for two hours in the twenty-four, & then in dubious twilight, an hour after sun-set & an hour before sun-rise.