FINDING NATURE'S TREASURES 139 
“No, she does not feed her babies insects,” Uncle Jack 
answered. 
“Does she feed them seeds ?” Fred asked. 
“No, she does not feed them seeds, either, when they 
are very young,” Uncle Jack again replied. 
“Well, then, does she feed them fish like the king¬ 
fisher, or mice like the owls?” demanded Marylee. 
“No, Marylee!” Uncle Jack smiled as he shook his 
head. “She feeds her babies milk.” 
“You must be joking, Uncle Jack,” said Buddy. 
“Surely, no bird makes milk the way cows and cats and 
dogs do. You said those animals were called mammals. 
Are turtledoves mammals, too?” 
“No, turtledoves and their relatives, the pigeons, are 
not mammals. They are birds. But they do feed their 
babies a kind of milk, called pigeon milk. The bottom of 
the bird's throat is enlarged and is called the crop. The 
milk is made in this crop. When the baby turtledove, or 
pigeon, is hungry, it puts its bill inside the mother's 
mouth. The mother bird makes the milk come up into 
her mouth where her baby bird may drink it.” 
“Is it like cow's milk?” asked Buddy. 
“It is almost like cow's milk except that it has no 
sugar in it,” replied Uncle Jack. Then he continued, 
“The doves and pigeons are the only birds that make 
milk for their babies. The old birds eat weed and grass 
seeds which they find on the ground. Sometimes they 
