The eggs being laid, the female soon commences to incubate. This seems to be the exclusive labor of the sex. The fact that she plucks the feathers from her abdomen, forming one or two bare spots (according to the number which is to compose her complement) with a ridge of feathers between them, though circumstantial in character, is the only kind of evidence that we have to offer in support of our assertion. Of the precise time required for hatching, we have no knowledge. From the size of the egg, and the thickness of its shell, we reason from analogy that it cannot be less than twenty-four days. The female is not a constant sitter during the daytime, the heated pebbles on clear, sunshiny days supplying the necessary warmth during her absence. When the weather is cloudy, and even during the cool nights, she remains on the nest, the male, as a faithful husband, doubtless answering her calls for food, or keeping her company.
That these birds manifest true affection for each other cannot be denied. They may have a different way of showing it from what we are accustomed to see among our small land-birds, but we cannot speak with positiveness. But this much is undisputed, when one is killed, its mate does not desert it, but paddles around it, as if seeking the cause of its stillness. At such times, so absorbed does it become, whether from grief or wonder we cannot say, that it can easily be approached and knocked over with an oar.
The food of the Razor-bills consists of small fishes, roe, shrimps, various marine animals, and floating garbage, which they procure by diving and swimming, or pick up among the rocks which they frequent. The young doubtless subsist upon the same materials, which they receive from their parents, in small pieces, during their earliest life. But after they have passed the downy stage, and are thrown, in a measure, upon their own resources, they imitate the example of their parents.
So much like the eggs of the Foolish Guillemot or Murre, already mentioned, are those of this species, that it is impossible to discern a characteristic so peculiar and persistent as to enable us to distinguish them apart. The ground-color is generally a pure-white; but specimens are often met with which are cream-colored, and others, again, which are tinted with green. The spots and blotches are irregularly distributed, but chiefly about the middle and the larger end. Some are small and nearly round, others large and irregular. In color they show different shades of black and brown. In addition to these markings, there are others scattered over the egg, of an obscure-purple hue, which have the appearance of being beneath the outside of the shell. The eggs vary in shape; occasionally they are pyriform and ovoidal, and, at other times, decidedly ovate.