HOUSE-MARTIN. 253 



the cliff-top I have dropped bits of cotton-wool and watched the 

 twittering Martins shoot out from the nests and catch the 

 floating scraps to add to the nest-lining. Even on the bare 

 cliff face the bird usually builds below some overhanging rock, 

 and on houses the nests are close under the eaves so that they 

 may be strengthened by attachment above (Plate 103). The 

 entrance is so small that the interfering Sparrow cannot invade 

 the sanctuary when once the nest is complete. The mud, 

 added in successive layers, is collected from ponds, streams or 

 puddles. In dry weather on the chalk hills I have seen a dozen 

 eager Martins gathered round a puddle left by a passing- 

 watering cart. Both birds work at construction, but before this 

 begins there is much play at building. A bird will fly up and dab 

 a pellet of mud on the wall, then cling with head turned, twitter- 

 ing invitation to its mate, who will settle alongside and both 

 will twitter conversationally. Then spreading their wings they 

 drop, perform a graceful arc and float off for aerial courtship, 

 returning shortly to the selected spot but doing no real building. 

 During construction there are frequent quarrels with trespass- 

 ing Sparrows, but I doubt if they often come to grips ; if the 

 Sparrow remains in possession the Martins build elsewhere. 

 The oft-repeated story of the owner of the nest calling other 

 Martins to its aid and walling up the hen Sparrow requires 

 confirmation ; it is in most books that children read, but lacks 

 the authority of a single ornithologist. 



At all times the Martin is sociable, and many nests are built 

 actually in contact ; probably the Yorkshire instance of forty- 

 six in a wall length of nine yards represents the greatest 

 number that could be crowded together. Eccentric nesting 

 sites are not common ; I have a photograph of one built upon 

 a telephone bell which was frequently used. Four or five white 

 eggs (Plate 84) are laid as a rule in early June ; second and 

 third broods are common, and late nestlings are often left to 

 starve. For weeks after leaving the nest the young congregate 



