RKRD-WARBLEB, 373 



we found no nests and saw no birds. The nests were very easy to find. 

 Some were long and tapering ; but most had little or no unnecessary foun- 

 dation. There were generally three or four reeds interwoven into the 

 sides of each nest. Swaysland had an idea that the nests were so built 

 that they could rise or fall with the rise or fall of the water ; but we found 

 that most had a leaf projecting close to the nest both immediately above 

 and below the nest on one or other of the reeds, which would make any 

 movement of the kind impossible. 



There was frequently a little wool or thistle-down used in the construc- 

 tion of the nest ; but dry grass-stalks aud roots were the principal materials. 

 Ten days later there would no doubt have been plenty of eggs; but we were 

 afraid that we were too late already. Possibly the cold weather may have 

 been the cause of the delay ; or it may perhaps be accounted for on the 

 theory that Swaysland caught most of the original settlers on this dyke, 

 and that the birds we saw were a later arrival of Reed-Warblers which 

 had been driven out of the adjoining dykes by their quarrelsome neigh- 

 bours. The eggs of the Reed- Warbler vary from -78 to '7 inch in length, 

 and from '55 to '5 inch in breadth, and are from three to five in number. 

 Dixon writes, " It is worthy of remark how very distinct generically the 

 eggs of the British Warblers are. The eggs in each genus, almost without 

 exception, are peculiar. Thus in the Willow- Warblers (Phylloscopus) we 

 have pure white eggs spotted with red ; in the Tree- Warblers (Hypolais) 

 the eggs are salmon-coloured spotted with purplish brown ; in the Grass- 

 hopper Warblers (Locustelld) the finely powdered markings of brown and 

 their general pinky appearance are characteristic of them alone ; whilst in 

 the Reed-^ arblers (Acrocephalus] greens and olive-browns are the predo- 

 minant colours. In the true Warblers (Sylvia), however, there is not so 

 much uniformity ; and this circumstance doubtless to some extent proves 

 the greater antiquity of these birds as compared with the birds of allied 

 genera. It seems to me that the very distinct variations in the eggs of 

 the true Warblers show a wide differentiation of many of the species ; but 

 in the allied groups (Acrocephafus, Lucmtella, Hypolais, Phylloscopus), 

 although the species have become fairly differentiated, the eggs have not 

 yet had time to vary, and consequently a certain type of egg runs through 

 each respective genus. What part these variations play in the economy of 

 the birds still remains to be discovered ; but I think it is very clear that 

 these well marked generic types of eggs prove a not very remote evolution 

 ot the birds in each of these genera severally from a common parent/ 5 



The general colour of the upper parts of the Reed-Warbler is olive- 

 brown suffused with rufous, especially on the rump and upper tail-coverts. 

 The eye-stripe is nearly obsolete; and the inuermost secondaries have 

 broad ill-defined pale edges ; the breast, flanks, and under tail-coverts are 

 rufous-buff, shading into nearly white on the chin, throat, and centre of 



