GOLDEN-CROWNED THRUSH. 



628 



FAMILY SEIUKIDAE. WOOD WAGTAILS. 



Priimries. nine. Bill, dt'stitute of i)rouiinuiit lulie nn cither maudilile. C'lracoid l).iiies slioi-tcr than the 

 top (if kcfl, the tip lit" which is proiluceil well fonneil. VViii;.^s. nut very pointed, the first, second and third 

 fpiills hein;z about e |u»l in lenj^th, and the win fs are much lon_^er th;in the S'[uare tail. 



The Inrds which I have thus elevated to the rank uf family, have fur u nuniher of years l:»cn placed 

 with the warblers, Imt I have never been satisfied with this arr;'n^einent. and in the first edition of this b)ok 

 placed theni as a i^enus of the Thrashes. I did this un ace nnit of the resemblance of tlie sternum to that of 

 members of thit fitnilc. ( Sc-e Fi.^ UIJ ) .^, where I i^'ive the keel of a Louisaria Water 'I'hrush. an<l cnipire 



with li, the keel 



Wi 



Thn 



see plate XX.VIIl. 



B 



V\. in_>. A. 

 Water Thnish, u 

 Thrush. 



Fij^s five an>l si.\, for sternum of Robin and com;)are all witii plate 

 XXXIV. Fig 1, sternum of Oraii;,'e Crowned Warl)ler. -t. of 

 Dine Yellow-back. 7 of Maryland Yellow-throat, 24. of Redstart, -(i, 

 Black and White Creeper ) lint alth^u^h they are evi:lently cl )sely 

 allied in many ways to the Thi-uslics, I lio not now consider that 

 they should be jilaced with that family. The Wood Wni^tails ditti'r 

 from the thrushes and the warblers, inasmuch as they walk and do 

 not hop when moving along a ]>laiii siirfaco : as in this and in some 

 keel of sternum of other habits, they appear to resemble the trtie Wagtails ( Mot rc- 

 suue of VViUju's Hi lac ) I have place I theui between that genus and the warblers. 

 Audoborn and some other of the oMer attthors considered them Wag- 

 tails, an arragement which did very well for a time when groups of 

 animals were much broader and more comprehensive than they are today. Now wo are learning two tliinws 

 in regard to systematic classification, one is that wc cannot crowil different species and genera into griups to 

 which they have no real affinity simply because they would otherwise stand alone : an I second, that we cannot 

 arrange groups of animals in regular sequence, one behind the other, and present a perfect chain of un- 

 broken relationships. 



The key note to the whole system of nature's relationships is struck by the oscillations of individual va- 

 riations ; when we study closely Ave find that the pendulum does not swing directly back anil forth, but de- 

 scribes an irregular circle with prominent points here and there. As it is with individuals so it is with 

 groups. This point may be illustrated by almost any group of birds ; take for example this very family of 

 Wood Wagtails : as shown, they strongly resemble some of the warblers, for they have nine primaries and a 

 form not unlike that of the members of the genus Oporornis ; in habit they are like the true Wagtails, while 

 in sternal characters, which are the least changeable of all, they are quite like the true Thrushes. 



GENUS. SEIURUS. THE WAGTAIL THRUSHES. 



Gen. Gil. Size medium. Sternum, precisely similar in form to that of the Thrushes, 

 and rather long in proportion to the size of the bird. 



Bill, conical 



SEiURUS AUROCAPILLUS 

 Golden-orowned Thrush. 



Seiurus aurocapillus Swainson. ZoologicalJournal, HI, 1827, 171. 



DESCRIPTION, 



Sp. Ch. Form, somewhat robust. Tongue, rather acuminate, slightly bifid and fringed with delicate 

 cilia for about one-si.\th of its terminal length. Marginal indentations of sternum not exceeding its breadth. 



Color. Above, pale olive green, with a broad central stripe of orange yellow on the head, margined 

 with black. Beneath, pure white, with numerous triangular spots of black upon the breast, flanks, and 

 sides of throat ; in the latter place they are clustered, forming maxillary stripes. A ring around the ej-c, and 

 the sides of the head, similar to the back, but paler. Flanks, olivaceous. Under wing coverts and auxil- 



