l;M UTLLKTIlSr 1-1. VNITKP STATKti NATION VI, MISKIM. 



I .c;iYO up liH^kitvsT for tho oiuraiuvs propor. iiiul siiwplv dug ni^ tho poat in iuvv" 

 si>i>t xhM jstvnuHl likolv to bo fivo frvMn riH^t*. I'nlos^ violoutb" disturlH\1. oaoh 

 bini \vo\jlt1 bo found jjittinc upon its Oirc. or porbaps it would baok awav a fow 

 jnch(p«s. 



Pootor Grit\iioll (ISi^T") savs: 



Mojit of tho burrows oaoh i\»ntaim\l an ogii. in which oasso ono bird, oithor 

 nialo or fv>inalo. wsis sitfiu^. In ease there was a youns: one. neither v'>:Hvnt 

 birtl was pri^ent. When thetv wore neither ecc nor yotnic in the hole, both 

 old binls wvre at houie toptnher. 



The southernmost oolony that 1 have soon dosoribod is ot\ tho 

 Th too Aroh "Rooks, off the coast of Ovooot\. of which Mr. W. L. 

 Finlov (UVX'i) has written a very interostiiiir aooour.t. lloro ho 

 found this species breeding with Kaediui: or Inil potrols, tufted 

 pnt^ins. western iriills. Brandt. Ixaird. and Faralloi\ cormorants, l^ili- 

 fornia miirres. and piofeon oinllemots. 



Eogs. — The sinjjle egii '^^ the forked-taiU\i petrol is nnich like that 

 of the T.eaoh potrek but soineAvhnt kirjror. Tho snrfaoo is smooth 

 but without jiloss, and the color is dull white. There are usually 

 pk^'nty of minute dark sj^eeks. purple or purplish bla-k in color, 

 forminpf a cloud or a wreatlt about tho laroer end. Sometimes those 

 spooks are quite hirge and conspicuous, but nioiv often very faint or 

 indistinct Some eggs show a few faint lilac spots. 



The measurements of 40 eggs, in various collections, .ivorage oo.l^ 

 by '.?r\7 millimeters: the largi^st eggs nioasin-e 87.5 by *2S.5 and o^.4 

 by 27. b. and the smallest eggs measure oQ bv 24.5 and 34 by 23.5 

 millimeters. 



Both sexes incubate, relieving each other at night and morning. 



Pftimaats. — The downy young when first hatched is covered Avith 

 lonjT. soft, thick down. foreshadoAving tho color of tho parent, except 

 on the chin and throat, which aiv naked. The color varies from 

 "deep mouse gray" or "light mouse gray'" above to "pale mouse 

 jirav Wlow." The young bird is nearly fully grown before the 

 plumaire appeal's. Oi tho devolopmotit of tho nhimago Mr. George 

 AViUett ( 101-2 "I writes: 



The first feathers to api>enr .«ire those of the winjrs and tail. eloseUv followeil 

 by those on the back of the hetxd and thrwit. Then i\uues the lieaiuiful gmy 

 ix>veTiivc of the back and upi>er tail-ooverts, and shortly afterwanl the mature 

 feathers replace the down on the chest. Tlie last do\\n\ to disjippear is that on 

 the lower abdomen. When this leaves the young is very similar in plutuasre to 

 the adult birtl. The tail, however, is not so dtvply forktnl. the white patch on 

 the throat is streakevl with gray, the forehead is dark gray instead of brownish. 

 and the genen\l ci>loration of the back, wings, and tail is darker thai\ in the 

 adult. 



Foorf. — The fotvd of the forked-tailed petrel ct^nsists of soft, oily 

 substances with perhaps a few minute ]\uti';los of animal food 



