CHAPTER XII 



Some Information About Their Characteristics, 

 Classification and Peculiarities — Ornithology 



THE pigeon tribe, comprising the large order of Co- 

 lumbae, contains many beautiful and interesting 

 birds, various families being styled doves in our no- 

 menclature of them and in our every-day language. 

 They are all distinguished from poultry and gallina- 

 ceous birds in general, by the form of the bill, which is 

 arched towards the tip, with a convex swelling at the 

 base, caused by a gristly plate covering the nasal cavi- 

 ties, which is curiously developed in some species. To 

 enable the parent birds to feed their young, the gullet 

 swells into a double crop, furnished with glands, en- 

 larged during their brooding season, which mingle their 

 secretions of certain acids with the food, to soften it 

 into an emulsion, similar to the milk of mammals ; or 

 thick cream combined with the casein, in consolidated 

 form, like the curds in making cheese from milk, so 

 when the birds throw up the food after their fashion, 

 to feed their young, the whole mass in the curd pouch 

 has a soft, pulpy consistence, suitable to the delicate 

 digestive powers of the tender young birds, and their 

 rapid growth is astonishing. 



The emulsion ducts of passenger pigeons, at breed- 

 ing season, expanded into visible white strings from 

 their breast to the curd pouch, outside of their feath- 



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