LIFE HISTORIES OF NORTH AMERICAN GULLS AND TERNS. 1S7 



female insisted upon Uuttering about and sittiiiij down so long at u certain 

 li'.ace on an island where the colony of rosy gulls and terns was situated that 

 I carefully marked the spot and examined it, hut only a tern's nest was there. 

 I thought at first that this was only an accidental occurrence, hut immediately 

 afterwards the same female rosy gull tried to attract my attention as per- 

 sistently to anoilier spot, lying still more out of my way, and anotlier tern's 

 nest was there. The terns understood these treacherous tactics quite well, 

 and at the la.st nest the female with angry screams engaged in a short battle 

 with the gull. 



riitiiHtiK s. — The newly liatclu'd gulls in down are scune 13 or 13J centimetres 

 in length, bur they grow (juickly and measure from 18 to liO centimetres Ity the 

 time that the feathers appear on the back and flanks. Eyes dark blackish 

 brown; legs and feet intense fleshy, tinged with gniy, r.v ilcshy gray, with 

 brownish claws; bill grayish fleshy with brownish tip. The ground color of 

 the downy dress is dusty yellow, varying in tinge irrespective oi growth; in 

 some examples it is pale sulpiiur-yellow, in others a soniewhat burnt wood- 

 yellow, occasionally, with a rusty tingi'. This ground color is densely covered 

 with numerous irregular and ill-defined blackish-gray markings, taking up at 

 least as much space as the yellow ground color itself. They are pale and quite 

 ill-defined on the flanks, while the middle of the bi'east and belly is without 

 them and whitish. They are sharply defined and nearly Itiack on the head, 

 where they are narrower. The markings vary in detail in ditfercnt specimens, 

 but in all the pattern is soniewhat longitudinal on the body, transvei-se on the 

 nape, and wedge shaped on the crown. This pattern is nuich obscured, especially 

 on the body, as the markings are so nnich broken up and wavy. Tlie sides of 

 the thmai, the eyebrows, and the down which covers the uppper mandible nearly 

 to the nostrils, are marked with dark color. 



Tlie feathers begin to appear first on the wings, and nearly at the same time 

 on the scapulars and tail; next on the upper part of back and on the flanks, 

 and then on the uropygiui.!. So fai- as can be seen tla^ new primaries are 

 blackish; the secondaries and tail feathers white; the tertiaries, wing coverts, 

 scapulars, and back featliers brownish black, with wide rusty-yellow' ends, as 

 are also U!)per tail coverts. Flank feathers and those of the uropygium white 

 rusty ends and blackisli-gray subapical portions. 



Tlie se(juence of pluma^^es to maturity can be only provisionally 

 inferred from the limited amount of material available for study. 

 Doctor Tiiitui'lin ( 11)00) irives us a very satisfactory and detailed 

 description of tiie Hi--t or juvenal plumao^e, the principal characters 

 of wliich are: " White under parts, tinned on the chest and bretist 

 with pale irrayisli citmanion buff: ui)per parts dark brown, barred 

 with ochraceoiis on the ends of the feathers; lesser wino;-coverts of 

 the foremost and inner half of the wing white, with narrow, ochra- 

 ceoiis tips; all the primary coverts blackish brown; the three inner 

 primaries practically blackish brown with the inner hidf of the inner 

 v.eb (excludino' the end) wliite; remaiiiiiio;; primtiries outwardly 

 edfi^ed witli bhickish brown, decreasing inwardly; and tail wliite, with 

 a narrow ochraceous tip and a blackish brown a])ical band." 



This pliiiiia<re is well ilhisl rated in XiUisen's (1S99) colored j)hite 

 of this species, based on specimens collected l)y his e.\'pe(btion near 



