ANGLE SEA BIRD-NOTES. 97 



impossible to give its numbers exactly, but at a rough estimate 

 there cannot be more than one pair to six or seven hundred or 

 perhaps a thousand pairs of the dominant species. In June, 

 1902, when one of the writers visited the place, there appeared 

 to be about the same number as now. The birds were not 

 segregated, but scattered among the Arctics all over the occupied 

 area, though at one spot there were three pairs close together. 

 We watched two birds on their nests, their mates standing 

 beside them. One was brooding on two, the other on a single 

 egg. The two eggs were on a few pieces of green sea sand-spurry 

 (Spergularia) in a narrow cleft in the rock-floor, into which the 

 bird appeared to be wedged when seen from a short distance. 

 The single egg was on a slight nest of dried pieces of spurry, also 

 in a cleft in the rock. 



Normal eggs of the Koseate Tern are easily distinguishable 

 from those of the Common and Arctic Terns, although the con- 

 trary has been frequently asserted. They are usually more 

 elongated ; the ground colour is creamy buff, varying in tone in 

 different specimens ; the markings are small, irregular, reddish 

 brown spots and streaks, usually distributed evenly over the 

 whole shell, but sometimes densest at the thicker end, where 

 they form an indistinct zone, and numerous underlying grey 

 spots and blotches ; the dark markings have very often a "run 

 in " appearance on the ground colour, and are very characteristic. 

 It may be that abnormal eggs of the Roseate sometimes approach 

 in character certain types of the Common and Arctic Tern, but 

 it is very doubtful if the converse ever occurs. The Eoseate 

 Tern shows a marked preference for rocky ground whereon to 

 lay its eggs ; these are generally in a cleft in the rock with 

 some pretence at concealment. Two eggs seem to be the usual 

 number, though one is not infrequent — three are exceptional ; 

 the number, however, may vary in different seasons and 

 localities. 



In the clear light of early morning, with the sun's level rays 

 striking the flying birds, the grey on the breasts of the Arctics 

 and the pink blush of the Eoseates was quite apparent when the 

 birds were viewed in an advantageous position ; but in many 

 lights it is impossible to distinguish the different Terns, whether 

 Arctic, Common, or Eoseate, by the colour of the breast as the 



Zool. 4th ser. vol. X., March, 1906. I 



