BUSTARDS, CRANES AND RAILS. 811 



big end. Erythristic colouring can be detected in some cases by 

 artificial lighting. Average of 100 British eggs, 60.8 x 42.29. Max. : 

 66.5x40.7 and 63.4x45.3. M3m : 55.6x41 and 64x38.9 mm. 

 Breeding -season. — First eggs may be found early in May but not 

 general till a week or two later. Incubation. — By both sexes . Period 

 36 days (incubator) : 5 weeks (Hantzsch). Single brooded. 



Food. — Mainly small fish (Animodytes tobianus and Clwpea imm&X .) 

 but also to some extent small Crustacea, especially Caridea (shrimps 

 and prawns.) 



Distribution. — British Isles. — Resident. Breeds sparsely. Isle of 

 Wight, mainland Dorset, Cornwall, Devon ; abundantly Scilly 

 Isles and Lundy ; many colonies Wales and northwards mainland 

 and isles, especially abundant Hebrides and Shetlands. Few 

 colonies east side Scotland, breeds Fame Isles (Northumberland) 

 and Flamborough (Yorks.), but not elsewhere east coast England. 

 Formerly bred Kent and Sussex. Abundant various parts Ireland. 

 Seldom near shore winter. Occasionally driven inland. 



Distribution. — Abroad. — Islands off Brittany, apparently those 

 formerly nesting on Heligoland, and southern Norway and 

 Sweden. Replaced by an allied form (F. a. arctica) on Bear 

 Island, northern Norway, Iceland, south Greenland and eastern 

 jST. America, and by another (F. a. naumanni) on Spitsbergen and 

 Novaya Zemlia, apparently also northern Greenland (?) and Jan 

 Mayen. 



Order ALE CTO RIDES. 



This is a useful division, but its limits and systematic position 

 have been differently considered. We look upon it as containing 

 Bustards, Cranes, and Rails, apart from some purely tropical 

 genera. The Alectorides may be said to stand between the Galli 

 (Game-birds), and Limicolo3, but could not be placed in a linear 

 arrangement of all orders. All are schizognathous and have 

 no basipterygoid processes. Vomer always present. Mandibles 

 without or with small processes. Sternum without spina interna. 

 Dorsal vertebrae not fused. Young when hatched with thick simple 

 downs, mostly strongly nidifugous. Eggs with bicoloured spots, 

 often very glossy. 



Key to families of order Alectorides. 



j /Xo hind-toe. Rectrices 18 to 20 Otididce 



\ Hind-toe present. Rectrices 10 to 14 . . . . 2 



.-, /Small and middle sized, tarsus much less than 100 mm. . Rallidce 

 \Huge, tarsus much over 100 mm. . . . Balearicidce (Gruidce) 



Family OTIDIDCE. 



The Bustards are a well limited family. So far as known their 

 cervical vertebra number 16 to 17. Bill short, as a rule shorter 



