VARYING FECUNDITY IN BIRDS 193 



lent example. Some years ago a few will provide examples of the biggest 

 well-known naturalists, whose experi- clutches ever recorded in the case of 

 ence was largely confined to single dis- every species of which a clutch is en- 

 tricts fell foul of each other in the col- countered. Some parts of Somerset- 

 umns of a natural history journal. One shire thoroughly illustrate this asser- 

 who lived in Ayrshire asserted that the tion. An afternoon on a large plain 

 yellowhammer never laid more than in that county, moist, loamy, dark- 

 three eggs in a nest, and that all the soiled earth, intersected by numer- 

 books were in error in crediting it with ous rhines and luxuriant hedgerows, 

 five or more. His country consisted yielded a nest of nearly every species 

 chiefly of sheep-farming land, alter- indigenous to the county, and all were 

 nating between rather thin, close- cram-full of eggs. Nearly every nest 

 cropped grazing ground and furze- we examined contained the maximum 

 clad moors, foliage and herbage being clutch which the authorities allow to 

 nowhere abundant. In the West of each bird, and in one or two cases the 

 England statistics showed that a clutch legitimate number was exceeded, as 

 of five was normal, while in the Mid- by a whinchat, which I found incuba- 

 lands again four was far commoner ting no less than seven eggs. Indeed 

 than either five or three. It is thus a friend remarked that all the birds 

 evident that the " three to six " of had passed their prescribed maximum, 

 the natural histories does not record with the solitary exception of a miser- 

 a varying energy or power of produc- able cushie, who had been content to 

 tion in each individual pair, so much deposit her regulation couple, 

 as the influence local conditions exer- All these tendencies are seen strongly 

 cise on the range of natural powers. marked when domestication gives any 

 On broader lines, the larger clutches species the certainty of ample nourish- 

 with which each species is generally ment for as many young as it cares to 

 credited by naturalists may be expected rear. The fecundity of pheasants and 

 in southern counties, and the smaller partridges and turkeys in semi-cap- 

 number is normal in the bleaker north, tivity is many times in excess of their 

 I know of no bird common in both capabilities in a state of nature, and 

 north and south which is more pro- is gradually being accompanied by a 

 ductive in the north. Occasionally a growing reluctance to incubate. The 

 day spent in abnormally rich country little finch now known as the domestic 



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