336 
OBSEltVATIONS ON 
do, make a smart snap; perhaps at that time they are^ 
jealous for their young, and this noise and gesture are- 
intended by way of menace. ^ 
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 its stem over the grass, as on the evening 
before. In May these birds find the Scarahmus melolontha 
on the oak; and the Scarahceus solstitialis at midsummer. 
These peculiar birds can only be watched 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-owl, 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 rudiments of 
young, and would have been hatched perhaps in a week. 
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 
summer; 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 were 
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 
