How Animals Work. 



truly remarkable nest, when cut out of the haystack, 

 weighed nearly eleven pounds, and measured thirteen 

 inches in length, by eight inches in its greatest width, 

 and four inches in thickness ; while it was lined with 

 fragments of the scaly inner bark of the fir tree. 



That extraordinary-looking bird the Hornbill, al- 

 though not strictly speaking a nest-builder, is yet some- 

 thing of a mason. Its nesting site is a convenient hole 

 in a tree, and within this hole the female bird actually 

 permits herself to be walled up by the male bird, who 

 plasters up the entrance to the hole with mud and clay, 

 leaving only a small opening through which he can 

 pass food to his voluntarily imprisoned spouse. This 

 curious habit is considered by some authorities as 

 probably a means of protecting the hen bird from the 

 attacks of monkeys and monitor lizards while she is 

 sitting on the eggs and brooding her young; and as 

 at the same time she appears to pass through the process 

 of moulting, when for a short time scarcely a flight 

 feather is left on her wings, she is safe from the danger 

 of toppling out of the nest and being * unable, owing 

 to the state of her wings, to return. But whatever 

 the reason, she is walled up by her truly devoted hus- 

 band when the time comes for her to sit upon the 

 eggs, and she does not regain her liberty until the young 

 are nearly, if not quite, fully fledged. During the whole 

 of this fairly lengthy incarceration the devoted male 

 bird mounts guard outside, and is busily engaged in 

 collecting and bringing back food supplies, first for his 

 wife, and later for both mother bird and hungry off- 

 spring, so that by the end of the nesting season he 

 presents a very careworn appearance, and is quite 



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