104 BRITISH BIRDS. [vol.xiv. 



seems to be indispensable and occupies much the larger 

 portion of the whole time spent ; this consists of incessant 

 hammering to produce a rough surface which will take the 

 subsequent stucco. Frequently it needs the most minute 

 inspection to detect the results of all this labour. The 

 amount of bark collected for the nest varies very much 

 according to the requirements of the cavity, and the part 

 taken by the male is also an uncertain factor. I have seen 

 him pull off a long strip from a birch tree, roll it up and hand 

 it over to his mate ; one year I observed him carry almost 

 his share to the box, but instead of entering it he would 

 endeavour to drop his pieces through the hole, with the 

 frequent result that they were blown back and lost ; again 

 this year, as far as I observed, his part was confined to 

 encouraging and guarding his mate while at work. I have 

 insufficient data to speak of the length of incubation, but 

 after they are hatched the young are usually a full 24 days 

 in the nest, leaving it in the first or second week of June. 

 The parents bring food, on an average, about once a minute 

 throughout the day, and at one nest I noticed the curious 

 fact that the young began to clamour, not before or during 

 a visit, but immediately after it. They are still fed very 

 assiduously for a long time after they are fledged, and the 

 hard-worked parent is worn to a shadow compared with the 

 plump offspring. 



This year I secured a more or less ready-made box from 

 the trunk of a hollow tree which had been cut down. Having 

 sawn off a portion about 15 inches in length, with a cavity 

 about 7 inches in diameter, I bored a lateral hole about 

 3 inches deep as an entrance, boarded up one end as a floor, 

 and supplied a removable slate roof. With some difficulty 

 this was securely fixed 12 feet up in the angle formed by the 

 twin stems of a Scotch pine. This faced a boys' playground 

 constantly in use, but within two days (February 23rd) a 

 pair of Nuthatches were overhauling it. By the middle of 

 March they were seriously thinking of nesting operations, 

 but for a week they could not make up their minds between 

 the attractions of this and another box with an entrance 

 hole large enough for an Owl. Finally their choice fell on 

 the new one, and the work began in earnest. The plastering 

 was not all done first, but from time to time was resumed 

 as a pleasant interlude during the laborious collection of 

 materials. The lower strata were composed of big coarse 

 bits of bark and debris from a place where trees had been 

 sawn up in the winter. These chips were often more than 



