27 2 THE SCOTTISH NATURALIST 



mainly indebted to notes placed in my hands at the time 

 by Miss D. Hamilton, Mr L. N. G. Ramsay, M.A., B.Sc, and 

 Mr A. G. Davidson : 



(i) Nothing unusual was noted in the last week of June, when 

 a small proportion of the eggs were already hatched. 

 On various dates during the first half of July, scores 

 of dead and few living young birds were found. In 

 the second half of the month the dead were numbered 

 in hundreds, while many living birds that had reached 

 full growth were too weak to fly, and younger birds 

 lay altogether helpless. 

 (2) Both Mr Ramsay and Mr Davidson state emphatically 

 that the death-rate was much lower along the dunes 

 near the seashore, where there is only bare sand with 

 scanty clumps of bent-grass. The high death-rate 

 prevailed where the bent-grass was abundant, or 

 where the ground was rough turf and moss. Mr 

 Davidson remarks on the difficulty the young birds 

 have of keeping above the drifting sand in the former 

 situation during high winds ; but during lighter winds 

 there might be no mortality from this cause, but dead 

 birds might soon be buried. This does not explain 

 away the comparatively great number of living birds 

 in this part of the colony, a fact for which it is 

 difficult to suggest a satisfactory cause : the slightly 

 smaller distance from the sea can hardly be material. 



(3) Deaths occurred freely at all ages from newly hatched 



to nearly full fledged, but adults were apparently 

 unaffected, only the usual occasional dead old birds 

 being found. 



(4) Unfortunately no dead birds were properly examined 



in 1910. It was noted, however, that many of the 

 dead had widely gaping beaks, as if they had died 

 gasping. No obvious injury existed in most cases, 

 while other bodies had apparently been gnawed by 

 rats. 



(5) Lack of food and the long drought were suggested causes 



of mortality, but Miss Hamilton remarks that the 



