264 OUR FAVOURITE SONG BIRDS 



intervals during the entire period of its sojourn 

 with us ; there is no special time at which the song 

 is more prominent than others, and we always 

 consider ourselves fortunate in hearing it. 



There can be no doubt that the House-Martin 

 pairs for life, and the old nesting-places — even the 

 old nests — are used years in succession. We know 

 of colonies of these species that were as busy and 

 thriving twenty or more years ago as they are 

 to-day. This Martin breeds almost as plentifully 

 on cliffs as on buildino^s, and seems to show no 

 special preference for either. Numbers of nests 

 are often made side by side, or more or less in 

 clusters. No other nest of any British species is 

 more openly exposed, neither is any other more 

 curious. It is variously built under eaves, in 

 corners of windows, beneath copings and ledges of 

 masonry, or in nooks of the cliffs — but everywhere 

 invariably under a projection of some kind. It is 

 shaped like half a basin, but some nests are much 

 more semi-conical than others. Externally it is 

 made of pellets of mud intermixed with bits of straw, 

 arranged course after course like bricks, and com- 

 menced at the bottom. This shell is lined with dry 

 grass and feathers. The aperture admitting the 

 parent birds is at the top, either at the front or on 

 one side, and is much narrower in some nests than 

 others. The birds will form nest after nest if it is 

 removed ; and show a most unaccountable prefer- 

 ence ^or certain spots. The eggs are from four to 



