THE COMMON HERON. 201 



less sociable at all times, its haunts are restricted only by nature of 

 its food ; is equally at home on broad waters of tidal estuary, low- 

 land river or mountain tarn. Size and coloration — pale grey with 

 white cheeks and fore-neck and black primaries — are as conspicuous 

 as is its gaunt figure, whether bird is wading in shallow water with 

 deliberate paces and neck outstretched or standing erect and 

 motionless, the neck sunk between the shoulders, on dead branch 

 of tree, edge of pool, sandbank, or pile of rocks near tide-line. 

 Equally unmistakable on wing : flight achieved by laboured beats 

 of large rounded wings, head drawn back between shoulders and 

 long legs trailing behind. Call, aloud, harsh "frarnk;" hunger- 

 cry of nestlings a chattering "tchuk, tchuk, tchuk," like Black- 

 bird's alarm-note. 



Breeding-habits. — Nests generally in colonies, in British Isles 

 usually in trees, but exceptionally on ground or among reeds, and 

 more frequently on low bushes or on face of cliffs. Nest. — Bulky 

 and flat, built of large sticks and branches and lined with twigs 

 when in tree, but in reed-beds of dead reeds. Dead grass also found 

 at times in lining. Eggs. — Usually 4 to 5, but instances of 6 and 

 even 7 on record, dull light blue-green, frequently splashed with 

 whitewash and sometimes stained with blood. Average size of 101 

 eggs, 60.2x43. Max. : 68.4x43.7 and 61.5x49.7. Min. : 55.4x 

 42.2 and 59.6x40 mm. Breeding -season. — Begins February, but 

 many birds do not lay till March. Incubation. — By both sexes, but 

 chiefly by hen ; period usually 26 days, but ranging from 25-28 

 days. From very late breeding records it seems probably some- 

 times double-brooded. 



Food. — Very varied ; mainly fish, but often small mammals and 

 amphibia. Mammalia include water-vole (many), brown rat, field- 

 mice, shrew, water-shrew, mole, and once bat ! Birds : Blackbird, 

 Waterhen, young Coot, Water-Rail, Dunlin, Snipe, young Terns, 

 Ducklings and once Swallow. Also frogs (many) and spawn and 

 newts. Fish of many species (trout, eel, perch, pike (up to 18 in.), 

 dace, roach, stone loach, miller's -thumb, sticklebacks, lamperns, 

 etc.). Also mollusca (fresh- water mussels, whelks and snails). 

 Insects : coleoptera (Dytiscus, Geotrupes, Aphodius, Coccinella, 

 Sitones, Agabus, etc.), diptera (Chironomus, Ceratopogon, Empis, 

 Bibionidce, etc.), neuroptera (Phryganeidce and larvae, Sericostoma, 

 Limnophilus, Corixa, etc.), hymenoptera (Ichneumon, Allantus, 

 Formica, etc.). Crustacea include crabs, prawns, shrimps. Also 

 earthworms and some vegetable matter recorded. 



Distribution. — British Isles. — Resident. Generally distributed, 

 breeding north to Orkneys (not Shetlands) and a few Outer Hebrides. 



Migrations. — British Isles. — Residents to some extent vagrant, 

 autumn to spring, visiting all coasts and outlying islands, so 

 evidence of true migration difficult to obtain. Double passage, 

 northern and western Isles of Scotland, latter half March to end 



