SAND-MARTIN 



of its beak in tin- actual work of excavation, the feet being then used 

 to scratch out the sand. Neither beak nor feet can be said to be 

 ^|i cially adapted tor <li in- and scratching, but they suffice. The 

 same may be said of the beak of the bee-eater, which likewise makes 

 burrows in sand, but which, unlike that of the sand-martin, is long and 

 curved. It appears to be even less adapted for the purpose of 

 excavation, if, as stated, the process has the effect of wearing it down 

 to half its length. 1 



The number of days it takes a pair to excavate and line a nest 

 varies of course with circumstances. Normally they work only a |>art 

 of each day, chiefly in the rooming, but, ax in the case of the other 

 Ilirnndinidm, wet and windy weather delay operations. Much no 

 doubt, again, depends upon the length of the hole and the hardness of 

 the earth in which it is made. A pair has been known to tunnel a 

 hole of 20 inches in forty-eight hours, but whether this was in soft 

 earth, or was a case of emergency owing to the advanced state of the 

 hen's ovaries, is not stated.* Another recorded period in sixteen days 

 for a four-feet hole. 3 More records are wanted in which the weather 

 and other conditions are closely noted. 



The sand-martin is one of the three British breeding Passerine 

 species that lays white eggs, the other two being the house-martin and 

 the dipper. 4 The spots occasionally found upon the eggs are doubt- 

 less due to deposits by the fleas with which the holes are often 

 infested. As Gilbert White observed, these pests "swarm at the 

 mouth of the holes, like bees on the stools of their hives." But they 

 are not, as he thought, bed-fleas. The sand-martin is privileged to 

 have a flea of its own, and this is not the only parasitic insect it has 

 to harbour. 5 



Whether both parents share in incubation is not yet certain, and 

 is, in fact, owing to the position of the nest, very difficult to determine. 



1 Yarrell, 7/w/ory of Bird*, ii. 440. 



1 Stui ler and Fatio. (Catalog der itMfcmfcii in hen Vogtl, Lief. ii. p. WL 

 Zoologist, 1840, 2000 (J. J. Briggs). 4 See vol. i. p. 811. 



* Letter to Harrington, February 26, 1774, 



