OYSTERCATCHER AND NATURAL ENVIRONMENT. 343 



under cultivation. On the south shore of the loch, the Lochan 

 a Chait, Frenich, and Cragan Dubh Burns have deposited cones 

 of alluvium, in that order from east to west. The cones are 

 margined by light grey shingle on the east and north aspects. 

 Towards the west the shingle thins out into a scanty fine gravel, 

 resting on the mud substratum. The shingle rarely exceeds 

 25 metres in breadth, and mostly is much narrower. The 

 eastern cone forms an old enclosed pasture, and shows very well 

 terracing into two levels. The large Frenich cone is under 

 arable cultivation, which, however, leaves a broad strip of turf 

 thinly planted with trees along its water margin. The western 

 cone is very small, and consists entirely of natural turf, thinly 

 sown with alders. Small sand-beaches are intercalated in the 

 shingle at places. The water is fairly deep on the east side of 

 the cones, shallow on the west, where mud-banks are forming 

 which expose at low water, and become then, like the mud 

 shore, more or less grass-grown. The true lake margin is not 

 evident on the beaches of the cones. The hillside behind the 

 southern shore shows heather and rock grading into natural 

 birch and alder wood towards the west. The north bank of the loch 

 is largely under arable cultivation. Within the area examined, 

 nesting is confined to the storm-beach and the beaches of the 

 alluvial cones. The ground behind the storm-beach and the turfed 

 portions of the alluvial cones form the local feeding-grounds. 

 The arable land at Frenich, Duntanlich, and on the north side 

 of the loch form the general or distant feeding-grounds. From 

 these, large quantities of Earthworms are brought to the young. 

 The local feeding-grounds provide tipulid and coleopterous larvae 

 in plenty. The true lake margin has a large invertebrate 

 population, but the beaches of the alluvial cones are deficient in 

 this respect. The open spaces in the woods also contribute 

 supplies. The whole of the breeding territories and local feeding- 

 grounds lie considerably below the 152 metres contour line. A 

 large sand-bank at the head of the loch, and a boulder area on 

 the north shore, near the exit of the loch, are used every year 

 by the birds that have failed to breed as places of assembly for 

 bathing, sunning, and other activities. 



4. River-valley Habitat. — A. The River Garry. The river in 

 the four kilometres of its course between Blair and Killiecraukie 



