Those of us who have been favoured with a peep into the extensive northern forests can understand why it is that the Birch Siskins are so rarely seen during the winter in Central Europe; they seldom need to migrate, the birch-trees of those woods producing in great abundance all that they require; it is only when their usual supply of seeds and fruits fails that these birds decide on removing for a time to more southern regions. Our readers will readily believe that this necessity is of very unfrequent occurrence, when we tell them that in cold northerly countries hundreds and thousands of square miles are entirely covered with trees, yielding the seeds preferred by these children of the forest. In short, the Birch-tree Siskin occupies the same position with regard to birch woods as does the Cross-bill to the tracts of fir and pine-trees, finding in them abundance of food during the winter months, and plenty of insects during their breeding season; indeed, the swarms of flies met with in these regions are prodigious, every tree or bush being often literally enveloped in a cloud of them. We have frequently been told that these birds will breed in Germany, but as yet no nests have to our knowledge been discovered so far from their usual haunts. Even in the north it is extremely difficult to find them, and for the first description of one we have to thank Boja, whose statements have been corroborated by Schräder. "You know," says the former writer, in a letter to his brother, "what difficulty I have had in my search after a Siskin's nest, and I should never have found it had not accident placed it in my possession. As I was descending a steep and almost naked precipice near Norwick my foot slipped, and I fell heavily into a cleft of the rock, disturbing by my fall a female bird sitting upon her nest, which was fixed upon the strong branch of a birch-tree, and contained four eggs, not larger than those of our Goldfinch, and of a greenish-white colour, marked with brownish red." The Birch Siskins usually make their appearance in Germany about the beginning of November, and that in very considerable numbers, though, as we observed above, their coming is by no means regular, and only takes place when they are driven from their native haunts by want of food. They usually select districts planted with alder or birch-trees, from whence they fly over hill and dale in company with Greenfinches, often passing the night upon the hedges, and feeding upon all kinds of oily seeds gleaned from the fields, but preferring those of the birch and alder. It is very evident when these birds first arrive in that country that they are by no means aware of their danger in venturing so near their arch-enemy man, but will come down and seek their food close to his dwellings, indeed it is only after repeated proofs of his treachery that they begin to lose their confidence and grow cautious and shy.