TTHIS species, which inhabits the coasts and islands of the north Atlantic and eastern Arctic ocean, and the Atlantic coast south to New Jersey, has the same general habits as the common Murre, which, like all the Auks, Murres and, Puffins, is eminently gregarious, especially in the breeding season. Davie says that tens of thousands of these birds congregate to make their nests on the rocky islands, laying single eggs near one another on the shelves of the cliffs. The birds sit side by side, and although crowded together never make the least attempt to quarrel. Clouds of birds may be seen circling in the air over some huge, rugged bastion, "forming a picture which would seem to belong to the imaginary rather than the realistic." They utter a syllable which sounds exactly like murre. The eggs are so numerous as to have commercial value, and they are noted for their great variation in markings and ground color. On the Farallones islands, where the eggs were until recently collected for market purposes, the Murres nest chiefly in colonies, the largest rookery covering a hillside and surrounding cliffs at West End, and being known as the Great Rookery. To observe the egg-gatherers, says an eye-witness, is most interesting. "As an egger climbs his familiar trail toward the birds a commotion becomes apparent among the Murres. They jostle their neighbors about the uneven rocks and now and then with open bills utter a vain protest and crowd as far as possible from the intruder without deserting their eggs. But they do not stay his progress and soon a pair, then a group, and finally, as the fright spreads, the whole vast rookery take wing toward the ocean. In the distance, perhaps, we see, suspended over a cliff by a slender rope, an egger gathering the eggs from along the narrow shelves of rock, seeming indifferent to the danger of the work." All this is now changed, the authorities having intervened to prevent the wholesale destruction of the eggs. The Western Gull, however, is another enemy of the Murre (the California species;) it carries off and devours both eggs and young. Mr. Bryant says the Gull picks up a Murre's egg bodily and carries it away in his capacious mouth, but does not stick his bill into it to get hold, as is stated by some writers, whose observations must have referred to the eggs already broken by the Gulls or eggers.

The eggs of Brunnich's Murre cannot be distinguished from those of the common species. They show a wonderful diversity of color, varying from white to bluish or dark emerald-green. Occasionally unmarked specimens are found, but they are usually handsomely spotted, blotched, and lined in patterns of lilac, brown, and black over the surface.