Both species of Murre laid their single peculiarly marked eggs on the bare shelves or ledges in the most exposed situations;^{89} and seeing them now for the first time in Nature, I was quite willing to accept the theory which has been advanced to account for their markedly toplike or pearlike shape. A round or elliptical egg, laid in the situations often chosen by the Murres, would, when moved by the wind or incubating bird, readily roll from its precarious position, but the pointed egg of the Murre when disturbed describes a circle about its own end. Thus, like a diplomat, it seemingly yields to superior force while retaining its original position. The eggs vary in color from greenish blue to buff, and are strikingly scrawled and blotched with shades of chocolate. No two are alike, a fact which it is supposed may aid the parent Murre in distinguishing her own egg among the dozens with which it may be placed. [Illustration: 90. Young Murres and egg.] The few eggs seen were doubtless laid by birds which had been robbed earlier in the season, but young were found in every stage, from the newly hatched downy chick,^{90} who sat on his narrow ledge vigorously screeching for food, to others half grown and with the natal down almost entirely replaced by the first winter plumage. The parents were still in attendance on the oldest birds, and no young were seen in the water. [Illustration: 91. Kittiwakes and young on nest. From the crate. × 2. An enlarged detail of No. 85.] Razorbills, perhaps because the Rock contained comparatively few of the sheltered nooks they require for nesting sites, were less abundant than Murres. Their downy young were much lighter in color than the young of the Murres, and their high squealing whistle could easily be distinguished from the screech of the young Murres. Of two specimens which had nearly completed the acquisition of their winter plumage, one had the white line from the eye to the bill so characteristic of the adult fully developed, while in the other it was wholly wanting—a variability in marking which suggests that the white stripe of the Ringed Murre is a similar individual peculiarity. Next to the Murres the Kittiwakes are probably the most numerous birds on the Rock. Doubtless for the reason that they select the less accessible ledges where their eggs can not be so readily taken, their young were more advanced than those of any other of the birds breeding here. Their nests, rather bulky structures of seaweed, which often projected well over the edge of the ledge on which they were built, contained only young with their parents, one or two birds constituting a brood.^{91} [Illustration: 92. Entrance to Puffin’s burrow.]