A Bird's Foot 195 



front and two behind, the outer one of the latter pair 

 being a reversed digit. Why some of the woodpeckers 

 should have four toes and others only three is an unsolved 

 enigma, and is especially puzzling in view of the fact that 

 the four- toed kinds do not seem to possess any advantage 

 over their cousins. The tridactyl species are as expert 

 climbers as any members of the family, and are extremely 

 hardy birds, too, some of them dwelling the year round 

 in cold northern climates, where the food question must 

 often be a serious one. 



Here is still another conundrum for the bird student : 

 Why do the four-toed woodpeckers have two hind digits, 

 despite the fact that they always clamber upward when 

 they take their promenades on the boles and branches of 

 the trees, whereas the agile little nuthatch, which glides 

 upward or downward, as the impulse moves him, has only 

 one rear toe and three in front, like the true perchers? 

 Nor is it less puzzling that the cuckoos, which are perch- 

 ing birds, should have two toes in front and two behind. 

 Then, there is the little brown creeper which never perches 

 and is forever creeping, creeping, upward, upward save, 

 of course, when it takes to wing and yet its toes are 

 arranged in the normal percher style, the hind digit having 

 an especially long, curved claw. It is a mistake to suppose 

 that all the problems of the bird world have been solved. 



Look at the different kinds of birds' feet and see how 

 wisely they have been planned for the various purposes 

 to which they have been applied. In order that a bird 

 may use his feet with the greatest dexterity in perching 



