TWELFTH ANNUAL REPORT. 63 



models, wliile the other has been filled by the Curator with various 

 interesting ornithological specimens illustrating the following : 

 The various shapes of birds' wings and their uses ; the relation 

 of a feather to the scale of a fish and the tooth of a shark ; the oc- 

 currence and adaptations of down in feathers, and the extracted 

 pigment of feathers, including pure metallic copper from the 

 wing of a tinamou. Here, also, are specimens of doves illustrat- 

 ing the Curator's experiments in regard to the effect of moisture. 



Relief from the confusion of construction and the constant 

 worry of new installations in the Bird Department has given op- 

 portunity for the inauguration of experimental work, and Curator 

 Beebe has devoted all spare time possible to the investigation of 

 a few of the many problems which ever confront the student of 

 ornithology and general evolution. In Mr. Beebe's researches 

 on the effects of unusual humidity, some very startling results 

 have already been attained, and were given immediate publication. 

 They now form Vol. I, No. i, of the new scientific publication of 

 the Society, entitled "Zoological and appear under the title 

 of "Geographic Variation in Birds, with Special Reference to 

 the Effects of Humidity." 



Another important problem now under careful consideration is 

 the cause of the seasonal change of color in such birds as the 

 scarlet tanager. Some interesting and unexpected results have 

 already been reached, and will soon be published. Investigations 

 of this character enter a totally unexplored field, where the way 

 must be slowly cleared by the elimination of negative factors be- 

 fore the dynamic phases of the problem can be reached and 

 submitted to critical investigation. In this work the keepers of 

 the Bird Department have taken a keen interest, and their cheer- 

 ful co-operation has been most helpful in the accumulation of 

 data in the new field of experimental ornithology. 



SUMMARY OF BIRDS LINING IN THE ZOOLOGICAL PARK 

 ON DECEMBER 3I, I907. 



Orders. Species. Specimens 



Rheiformes, Rheas i 2 



Struthioniformes, Ostriches 2 3 



Casuariformes, Emeus and Cassowaries. . 2 4 



Tinamiformes, Tinamous 2 4 



