224 HIRUNDI>fID.E. 



thus completed is frequently occupied by both birds at the 

 same time, who thus appear to enjoy the habitation their 

 united industry has achieved. In some instances these birds 

 build under projections against the surface of high cliffs, as 

 those referred to by Mr. Couch on the Cornish coast, and 

 others mentioned by Mr. Selby as occurring about St. Abb's 

 Head, on the coast of Northumberland. 



The Martin produces three, and sometimes even four 

 broods in the season. Dr. Jenner, writing from home, says, 

 " A pair of Martins hatched four broods of young ones in the 

 house of a tradesman in this place in the year 1786. The 

 latter brood was hatched in the early part of October. 

 About the middle of the month the old birds went off, and 

 left their young ones, about half fledged, to perish. The 

 pair returned to the nest the 17tli of May, 1787, and threw 

 the skeletons out." 



The eggs are four or five in number ; they arc smooth and 

 white, measuring nine lines and a half in length, and six 

 lines in breadth. Incubation lasts thirteen days. The 

 young are at first fed by the old birds going into the nest to 

 them ; after a time the young thrust their heads out at the 

 opening on the arrival of either parent bird, who feeds them 

 while hanging on by their sharp crooked claws to the rough 

 outside of the nest. The old female begins to lay again as 

 soon as each young brood is able to leave the nest. As 

 the season advances a smaller number of eggs are produced ; 

 but White says they are never without unfledged young ones 

 as late as Michaelmas. 



The subject of the Martins deserting their young has been 

 adverted to. This singular fact in their economy has been 

 particularly attended to by Mr. John Blackwall, and the 

 following particulars are derived from that gentleman''s pub- 

 lished " Researches in Zoology." It did not come to my 

 knowledge that these late broods arc sometimes deserted by 



