BREEDING COLONIES OF THE BLACK-HEADED GULL 77 



An interesting fact in connection with this gullery may 

 be mentioned, namely, that a few nests occur annually in 

 stunted fir-trees at the upper end of the marsh. On 7th 

 May 1917 I shook an egg from a nest placed 10 or 11 feet 

 from the ground in a small Scots-fir ; the nest, which was 

 made as usual of dead rushes and grass, had for foundation a 

 layer of twigs, probably the remains of that of a Wood- 

 pigeon. From another nest, at a height of about 8 feet in a 

 flooded Scots-fir, three eggs were obtained on 13th May 

 1919. I may also mention that on 29th April 1916 1 found, 

 lying dead at the edge of this breeding-place, a Gull (male) 

 which had acquired the black hood while still retaining the 

 black-tipped tail feathers of immaturity. Similar birds have 

 been seen at other colonies. 



Harperrig Reservoir^ at the foot of the Pentlands a few 

 miles south-west of Mid-Calder Station (Kirknewton). This 

 reservoir was constructed, I understand, in 1855-6, The 

 main nesting-place of the Gulls is near the head of the 

 reservoir on what is more or less of an island according to 

 the height of the water. How far back the colony dates 

 I cannot say ; its existence, however, has been known to me 

 for forty years. My first actual visit to it was made on 20th 

 May 1882. Failing to reach the nests that day, I returned 

 on the 26th, and by means of a boat was able to land on the 

 island. My notes record that nests were plentiful, mostly 

 containing deeply incubated eggs, and that some young had 

 already hatched out. The habitat was revisited in the 

 breeding seasons of 1883 and 1884, when the birds were 

 still noted as numerous. I do not appear to have made any 

 specific estimate of their numbers on these occasions, but 

 I feel sure there were not less than 100 to 150 pairs, and 

 visits to the locality in 1890, 1897, 1903, 1905, etc., did 

 not reveal any marked change in the size of the colony. 

 Later there would appear to have been an increase culminat- 

 ing, Mr White, the keeper of the reservoir, tells me, in 191 5, 

 when he considers there were at least 250 pairs. After this 

 their protection was suspended owing to war-time scarcity 

 of food, with the result that a rapid decrease has since taken 

 place, so rapid indeed that last year (1919) there were 



