REMARKABLE DISPLAY OF INSTINCT. 45 



cause of suspicion as to the stability of the edifice, 

 a martin had recourse to the wonderful expedient 

 of working in a straw, as a binding beam along 

 the curve of the structure ! The ends were, it 

 seems, secured without difficulty ; but the efforts 

 of the little builders to bend down the arch formed 

 by the rising of the middle were in vain ; for when- 

 ever the pressure was removed, it persisted in 

 maintaining its elasticity. The baffled bird glanced 

 about, as if in contemplation of the difficulty, and 

 seemed ready to receive any suggestion which 

 might be offered, till, tired of watching the inva- 

 riable result of so many efforts made in vain, the 

 observer walked on. Eeturning an hour or two 

 afterwards, the little architect was observed to 

 have resorted to the only plan which could be 

 effectual : he had left the ends free, which thus 

 projected a little from the mortar, and the struc- 

 ture was complete at last." 



These materials are not without their disadvan- 

 tages. It has been well remarked, that no bird suf- 

 fers so frequently from the peculiar construction 

 of its nest, as the house-martin.* The rook will at 

 times have its nest torn from its airy site, or have its 

 * Knapp : Journal of a Naturalist. 



