LETTERS 



"OX INCUBATION." 



To the Editors of British Birds. 



Sirs, — I read Mi'. Dunlop's interesting article " On Incubation " 

 in yoiu' May number (Vol. V., pp. 322-7) with much interest, and also 

 the letters from Messrs. J. Lewis Bonhote and C. L. Collenette in your 

 June issue (Vol. VI., pp. 29-30). 



I do not agree with Mr. Bonhote in his remarks re the breeding of 

 domestic pigeons. I am willing to grant that in the majority of cases 

 the incubation period in domestic pigeons commences on the laying 

 of the second egg, but this is not a universal law. 



In domestic pigeons, as in the wild Columbarian races, the female 

 lays her first egg and then allows a full day to elapse before the second 

 egg is laid. If the female was the only factor as regards incubation, 

 that first egg would not be incubated but merely stood over at night 

 vmtil the second egg appeared, and then incubation would begin and 

 both the yoimg ones would be hatched simultaneously on the twentieth 

 day from the laying of the first egg. As a matter of fact, in the pigeon- 

 world, the male also takes his due share in incubation, i.e. the female 

 incubates from 4 p.m. to 10 a.m. and the male from 10 a.m. to 4 p.m., 

 and it entirely depends on the individuality of the male as to whether 

 the first egg is incubated before the second egg appears or not. Certain 

 males never begin their incubating duties imtil the second egg is laid, 

 other males begin incubation as soon as the first egg appears, and in 

 this latter case you find that the first egg laid hatches on the eighteenth 

 day and the second egg not till two days later, and owing to the 

 difference in size, the second yoimgster nearly always dies, owing 

 to the older, and therefore stronger, youngster always getting the 

 parents' first attention as regards food; if however the parents happen 

 to be good feeders, the second youngster may live, and in many cases 

 does so, but always remains smaller and weaker than the first-hatched 

 young one. 



With the rest of Mr. Bonhote's letter and the whole of Mr. Collenette's 

 I entirely agree. F. W. Smali.ev. 



To the Editors of British Birds. 

 Sirs, — Mr. Bonhote, in his criticisms of my article on Incubation 

 (Vol. v., pp. 322-7) states that I do not differentiate sufficiently between 

 " standing over eggs " and incubation proper, and cites his experience 

 of domestic pigeons in support of this statement. He says " it is the 

 common and normal practice among domestic pigeons " for one of 

 the birds to be constantly on the nest after the deposition of the 

 first egg, but that incubation does not commence imtil the second 

 egg has been laid, " the young mvariably hatch out practically siinul- 

 taneously." In my paper I recorded the result of observations in 



