336 OBSERVATIONS 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 Scarabceus melolontha 

 on the oak ; and the Scarabceus 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- 

 owl's 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 



