HOODED CROW 297 



with semiclosed wings, and sometimes a. half-roll, bird croaking continuously. 

 Aerial display in spring also includes "corkscrew" or figure-of-eight flight high 

 in the ajr by a pair of birds. This is also accompanied by much calling. Another 

 form of posturing several times watched by us shows the male bird, while perched 

 on a tree bowing to the female. In this display, carried out several times in 

 succession, wings are spread and tail expanded. In April, 1940, we watched coition 

 of Hooded Crows take place on a bare, burned patch of moorland. Prior to the 

 act the male for over a minute violently shook his raised wings and this he also 

 continued after coition. 



It appears from this description, as might be expected, that the court- 

 ship and sex behavior of the hooded crow differ in no respect from 

 those of the carrion crow. 



Nesting. — The hooded crow will nest either in trees or on some ledge 

 of a coastal cliff, generally protected by an overhang of the rock. Un- 

 like those of the rook, which likes to build in the slender topmost 

 branches, tree nests are generally placed in a comparatively stout fork. 

 Inland, even in localities where trees are rare or absent, it rarely builds 

 in cliffs or rocks but quite frequently places its nest in bushes, some- 

 times quite low. Ussher and Warren (1900) state that in the west of 

 Ireland, where it habitually breeds in bushes in this way, it usually selects 

 one on an island in a lake, no doubt for greater security. Occasionally 

 a nest may be built on the ground among heather on low islets in lakes. 



The nest, which is built by both sexes, the male doing most of the 

 collecting and the female most of the building, is described by Jourdain 

 (1938) as "strongly constructed of sticks, heather-twigs, seaweed-stems, 

 moss, and earth, lined wool, hair, and sometimes feathers." These 

 crows usually employ a quantity of wool in lining their nests, in con- 

 trast to the rook. Jourdain also mentions that in the Shetland Islands 

 and northern Ireland large bones have been found in the foundations of 

 nests. 



Eggs. — The following condensed particulars are given by Jourdain 

 (1938): "Usually 4-6, very rarely 7; much resemble Carrion-Crow's; 

 ground-colour varying from light blue to deep green, generally blotched 

 and spotted over whole surface with shades of umber-brown, and under- 

 lying ashy shell-marks. Some have only few markings on blue ground 

 or are entirely devoid of them : one light-coloured tgg in clutch not un- 

 common. Erythristic variety recorded once or twice. Average size of 

 100 British eggs 43.5 x 30.3. Max.: 52.0 x 32.0 and 43.4 x 33.0. 

 Min. 39.2 x 29.8 and 44.3 x 28.4 mm." 



Eggs may be found at the end of March and in April in the British 

 Isles. 



Young. — The incubation period is 19 days and is performed solely by 

 the hen bird, who is fed by the cock. The feeding may take place al^ 



