384 A PRACTICAL HANDBOOK OF BRITISH BIRDS. 



than 10th primary, tips rounded. Tail graduated, two central 

 pairs longest, rest graduated, outermost 7-14 mm. shorter than 

 central, 12 feathers, tips somewhat pointed, webs being sharply 

 sloped off. Bill fine, base slightly flatter and broader. Some fine 

 rictal and nasal bristles. Nostrils not covered by feathers. 



Soft parts. Bill blackish -horn, base of lower mandible pinkish- 

 yellow ; legs and feet deep straw ; iris and orbital ring bright 

 yellow-brown. 



CHARACTERS AND ALLIED FORMS. S. u. undata (south Europe) is 

 considerably more slate-grey and paler on upper-parts and rather 

 paler on under -parts ; S. u. aremorica (north-western France) is 

 said to be slightly paler on upper -parts than British form ; S. u. toni 

 (north-west Africa) is like typical form but slightly smaller ; 8. u. 

 corsa (Corsica, Sardinia) is as small as last but has paler and more 

 vinous under -parts. Small size, dark colour and long graduated 

 tail easily distinguish it from other British warblers. 



FIELD-CHARACTERS. Small size, dark coloration and long tail, 

 which it has a habit of holding fairly erect, makes Dartford Warbler 

 easy to distinguish when seen. But except in very bright weather, 

 when it fairly frequently appears for a moment on top of a gorse 

 bush, or when it has young and becomes much bolder, it requires 

 patient watching to see it emerge from thick cover of gorse and 

 heather it frequents. Harsh, somewhat prolonged " tchirr " 2 or 3 

 times repeated is very distinctive, sounding occasionally like White- 

 throat's note but of a different quality and not to be confused when 

 once known. Also has rather soft " tut " alarm-note and a beauti- 

 ful little song. Flight weak and wavering and generally quite close 

 to ground. (H.F.W.) 



BREEDING-HABITS. Nests either in long heather or gorse. In 

 heather it is generally low down, but in gorse is found at varying 

 heights. Nest. Compactly built of bits of ling, grasses, moss, etc. 

 (when built in heather may be found almost entirely built of bits 

 of ling), lined with a few feathers, roots, and hair, and studded 

 externally with cocoons of spiders. When in gorse, dwarf-furze 

 is also used as nesting-material. Eggs. Normally 3-4, occasionally 

 5, white or greenish in ground-colour, finely spotted with olive- 

 brown and leaden -grey, sometimes evenly distributed or forming 

 zones or caps at large end. Average of 100 eggs, 17.5 x 13.2 mm. 

 Breeding-season. Variable, but most eggs laid about May 20, though 

 fledged young have been found on May 3 and fresh eggs late in 

 June. Incubation. 12-13 days (Walpole Bond) : about 12 days 

 (M. B. Holcombe), chiefly at any rate by hen. Fledging -period. 

 About 13 days. 



FOOD. Chiefly insects : small coleoptera, lepidoptera (butterflies, 

 moths large and small, caterpillars) : diptera (Tipula, Muscidce, 



