614 OHIO BIRDS. 



species are witliaut ■wing-bars, while in D. palmarum, so far as known the only groand- 

 nesting DeadrcBoa, the wing-bars are wanting. In this family the presence or absence 

 of wing-bars seems to be aflsaoiated with the presence or absence or more or less perfect 

 developement of tail spots (not tail-tips, however, in the sense used above), except in the 

 case of Myiodiootea mitratus where wing-bars are wanting but tail spots are well developed. 



It may be further said with regard to the presence of wing-bars that they seem to be 

 more perfectly developed in the northern than in the southern birds of a genus. 



I have brought before you many specimens of our Ohio Birds for the purpose of inquir- 

 ing into relations which exist between the color or pattern of coloration and the mean 

 annual temperature to which these birds are subjected. In this investigation, I shall 

 assume that birds which are only winter visitors with us are subject to the lowest tem- 

 perature ; that thoie which are resident throughout the year with us are next in order 

 in this respect, while summer residents may be considered as subjected to the highest 

 average temperature, and spring and fall migrants to an average temperature higher 

 than that of residents. 



There K a well-known law that when the adult male and female of a species resemble 

 each other the young differ from either parent ; and, when the adult male and female 

 are unlike, the young resemble the female. I wish now to make a series of comparisons 

 showing the relations between young of different species, or the young of one species 

 ■with the adult of another. But first I will call your attention to a few birds for the 

 purpose of illustrating the law of resemblance or difference between the young and old 

 of the same species. We have here the male and female of one of our most common 

 birds, the Robin, Turdui migratoriiu, and they will be seen to resemble each other very 

 closely both as to pattern of coloration and color. Their young, however, differ both 

 in odlor and pattern. In the other case, we have the Purple Pinch, Carpodaous pur- 

 pureua, the male of which is adorned with bright though shaded or blended colors, 

 while the female is much plainer, lacks the bright color and is thickly dusky- streaked. 

 The sex of the young male could not be determined by the markings or color, as in both 

 these the resemblance to the female is almost perfect. In some oases the male and fe- 

 male differ in eolor but not in pattern, as here in the case of the Tawhe Bunting (Pipilo 

 erythropTithalmus). In this case the young bird differs from either parent. 



There appear to be among young birds three distinct primary patterns of plumage, 

 the spotted, barred, and streaked ; in the developement ef the individual these may re- 

 main permanently, and more or less completely, or be transformed into another pattern 

 by the blending of two of these, or into definite or indefinite color areas. 



In making the following comparisons between birds of our own State, our point of 

 observation, in this city, is favorable, being central and very near the fortieth degree of 

 latitude. 



I have here six birds, all of them True Thrushes and all of different species. Five of 

 these present on their under parts a more or less distinctly spotted pattern while the 

 sixth is uniform or nearly so in the region where the others are spotted. Yob recognize 

 this sixth specimen as the Robin, Turdus migratorius, of which I made use in illustrat- 

 ing the differences between old and young birds. On comparing the young of the Robin 

 ■with the other five Thrushes, the pattern of coloration is seen to T»e the same. 



If now we arrange these birds, placing that bird first whose southern breeding limit, 

 80 far as known, is most northerly, and the others following in the same order we have : 



1, Turdus alicise, 



2, Turdus swainsoni. 



