Broad-Tailed Humming Birds 



the young birds is very interesting. It is sev- 

 eral days before pin-feathers appear, and the 

 bill lengthens very slowly. At the age of 

 twelve days, the eyes are opened now and then 

 for a few seconds only, being as yet very weak. 

 About this time, when young yellow warblers 

 would already have left the nest, the hummers 

 are still in the pin- feather stage, and the bill 

 has become about half adult length. Not un- 

 til they are nearly three weeks old, do the 

 young begin to look like real humming birds. 

 Although my observations did not continue 

 until the young left the nest, I judge from 

 their rate of growth, that their bills do not be- 

 come adult length at much less than four 

 weeks from the time of hatching. 



The entire work of building the nest, incu- 

 bating, and raising the young falls on the in- 

 dustrious little female. Never once did I see 

 a male around any of the nests visited. The 

 mother hummer frequently feeds her offspring 



25 



