72 
THE NATURA.L HISTORY 
[LETT. 
young ; and their noise and gesture are intended by way of 
menace. 
Fern-owls seem to have an attachment to oaks, no doubt on 
account of food ; for the next evening we saw one again several 
times among the bouglis of the same tree ; but it did not skim 
round its stem over the grass, as on the evening before. In May 
these birds find the Scarahceus mcloloiitlm on the oak ; and the 
Scarahojiis solstitialis at midsummer ; but they can only be 
v/atched and observed for two hours in the twenty-four; and 
then in a dubious twilight an hour after sunset and an hour 
before sunrise. 
On this day (July 14, 1789) a woman brought me two eggs of 
a fern-fowl or eve-jarr, which she found on the verge of the 
Hanger, to the left of the hermitage, under a beechen shrub. 
This person, who lives just at the foot of the Hanger, seems well 
acquainted with these nocturnal swallows, and says she has 
often found their eggs near that place, and that they lay only 
two at a time on the bare ground. The eggs were oblong, 
dusky, and streaked somewhat in the manner of the plumage of 
the parent bird, and were equal in size at each end. The dam 
was sitting on the eggs when found, which contained the rudi- 
ments of young, and would have been hatched perhaps in a 
w^eek. From hence we may see the time of their breeding, 
which corresponds pretty well with that of the swift, as does 
also the period of their arrival. Each species is usually seen 
about the beginning of May. Each breeds but once in a sum- 
mer; and each lays only two eggs. 
July 4, 1790. The woman who brought me two fern-owls' 
eggs last year on July 14, on this day produced me two more, 
one of which had been laid this morning, as appears plainly, 
because there was only one in the nest the evening before. 
They were found, as last July, on the verge of the down above 
the hermitage under a beechen shrub, on the naked ground. 
Last year those eggs w^ere full of young, and just ready to be 
hatched. 
These circumstances point out the exact time when these 
curious nocturnal migratory birds lay their eggs, and hatch their 
young. Fern-owls, like snipes, stone-curlews, and some other 
