3S8 NATURALIST'S CABINET. 



Difference ol the crop during incubation. 



sitting, "ith its appearance on these occasions, 

 the difference is found to be very remarkable. 

 In the first case it is thin and membranous; but 

 when the young are about to be hatched, it be- 

 comes thicker, and takes a glandular appearance, 

 having its internal surface very irregular. What- 

 ever may be the consistence of this substance 

 when just secreted, it probably very soon coagu- 

 lates into a granulated white curd ; and in this 

 form it is always found in the crop. If an old 

 pigeon be killed just when the young ones are 

 hatching, the crop will be found as above de- 

 scribed, having, in its cavity pieces of white curd 

 mixed with the common food of the bird, such 

 as barley, pease, &c. The young pigeons are 

 fed for a little while with this substance only : 

 about the third day some of the common food 

 is to be found along with it. As the pigeon 

 ,grows older, the proportion of common food is 

 increased; so that by tb.e lime it is seven, eight, 

 ,or nine days old,, the secretion of the curd ceases 

 in the old ones, and of course no more is found 

 in the crop of the young. It is a curious fact, 

 that the parent pigeon has at first a power to 

 throw up this curd without any mixture of com- 

 mon food ; although afterwards both are thrown 

 .up in the proportion required for the young ones. 

 Multitudes of wild-pigeons visit us in the win- 

 ger, from their more northerly summer retreats; 

 appearing about November, and again retiring 

 (except a few that breed with us) in the spring. 



