'TWIXT COLD AND HEAT. 75 



birds suffered no further annoyance, and reared their 

 brood without mishap. 



Why should not these sparrows, iq^ the first two in- 

 stances, have utilized the material for their nest which 

 I offered, rather than gather similar stuff from distant 

 points? They could not have been frightened by any 

 odor attached to the material through my handling, as 

 I was careful not to touch a particle of it, using a pair 

 of wooden tweezers in every case. Neither did they see 

 me carrying anything to or from their nests. As these, 

 in all cases, were nearly or quite completed, the birds 

 had necessarily become thoroughly familiar with the 

 surroundings, and doubtless recognized the fact that 

 these offered twigs and the hair were brought by unusual 

 agencies to the spot, thus arousing suspicion, as I have 

 pointed out. When a nest not of their building was 

 substituted for their own, the sparrows were sorely per- 

 plexed and exhibited fear, and only after a strong men- 

 tal effort — of itself a telling evidence of intelligence — 

 the maternal instinct overcame the timidity of the fe- 

 male, and she resolved to brave the danger or solve the 

 mystery, and cared for her eggs as usual. The male 

 bird kept aloof for several days, I think ; but of this I 

 am not positive. These several incidents, collectively 

 considered, clearly demonstrate that this social sparrow, 

 which under other circumstances is so tame and unsus- 

 picious, when nesting is wisely cautious, never acting 

 without due consideration of the probable results. 



But it is not every bird that is so particular as to the 

 origin or location of suitable nesting materials. Only 

 a few days ago I found a pair of English sparrows and 



