NESTING-SERIES OF BRITISH BIRDS. 17 



No. 46. WILLOW- WARBLER. 



(Phylloscopus trochilus.) 



This Warbler makes its appearance about the first week in April and 

 is common throughout the British Islands till the end of September or 

 even later. It frequents gardens and coppices, feeding principally on 

 small insects, especially flies and aphides. The dome-shaped nest, 

 loosely constructed of dry grass and always lined with feathers, is usually 

 placed among herbage on the ground. From six to eight white eggs, 

 generally spotted with light red, are laid in the beginning of May, and 

 two broods are often reared in the season. 



Norfolk, June. 

 Presented by Lord fValsingham, F.R.S. 



No. 47. SAND-MARTIN. (Cotile riparia.) 



No other Passerine bird has so wide a range as the Sand -Martin, 

 which occurs throughout the greater part of Europe, Asia, Africa to the 

 southern portion, and America, extending in winter as far south as 

 Brazil and Peru. It is one of our earliest spring visitors, arriving 

 towards the end of March and departing by the end of September. It 

 is generally, though locally, distributed in colonies all over the British 

 Islands, wherever the steep banks of rivers or lakes, sand-pits, gravel- 

 quarries, or railway-cuttings offer a suitable nesting-site. In such 

 situations tunnels, varying from eighteen inches to six feet in length 

 and slanting slightly upward, are bored by the birds, the nest of dry 

 grass, lined with feathers, being placed in an enlarged chamber at the 

 end. From four to six white eggs are laid about the middle of May, and 

 two broods are generally reared in a season. 



The model exhibited is an exact representation of a portion of the 

 side of a disused sand-pit occupied by a colony of Sand- Martins, and 

 the dimensions of each tunnel were carefully measured. The two lateral 

 tunnels have been opened to show their structure. 



The measurements are as follows : — 



Tunnel no. 1, 2 ft. long ; nos. 2 & 3 run into a common passage, 2 ft. 

 8 ins. ; nos. 4 & 6, 2 ft. 4 ins. ; no. 5 was abandoned, a stone preventing 

 the birds from completing it ; no. 8, 2 ft. 7 ins. ; nos. 7 & 9, 3 ft. 3 ins., 

 extended beyond the back of the model. 



Norfolk, July. 



Presented by Lord Walsinyham, F.B.S. 



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