Mr. Cordeaux has already shown to us the apparently abnormal statistics on the south coast of England, birds crossing towards England and flying north-west all through the migratory season between August 16th and December. I am inclined to look upon these data as indications of the wide-spread waves of the general migration, extending both farther north and farther south. According to the amount of pressure at the starting-points [or possibly the increased area northward occupied in a particularly fine nesting season, as in 1880] will the wideness of the area be which is passed over by the migratory flocks. I think the rules known to apply in the dispersal and extension of range of species are, in some respects, applicable also to the greater and more extensive waves of migration.

I could say more regarding the peculiarity of nesting sites being occupied year after year by the same pairs of birds, or of well-known sites being vacated for a few seasons, and again occupied; or I might dilate upon some curious statistics of the continuous recurrence of foreign species at the same localities, or along the same line of country, but I fear to occupy space with theory only, until we have a larger accumulation of solid material.

As regards severity of weather apart from winds, unusually early winter was reported from Scandinavia, it having begun there in October (vide 'Field,' Oct. 16th, 1880, p. 590).

Attention should be drawn also to the admirable work being done on the subject of migration by Mr. J. J. Dalgleish (Bull. Nuttall. Orn. Club), and by Mr. Percy E. Freke (Sc. Proc. Ryl. Dub. Soc, vol. ii., n. s., p. 373, and vol. iii., n. s., separate?). These gentlemen also now propose to colour, or have already finished, maps showing the distribution of the occurrences of American birds in Europe recorded in their papers, which cannot fail to be of much service in our work. We would like to see not only American species mapped out in Europe, but rare European occurrences in Great Britain.

Finally, in endeavouring to arrive at conclusions regarding the causes of migrational phenomena in 1880, we have taken into consideration—1st. The value of the heights of lanterns above the sea, as against the colour and intensity of lights in 1879; and we have taken more account of the vertical area of birds' flight in 1880 than in 1879. 2ndly. We have compared the effects of prevailing north-west winds in 1879 pressing laterally upon the lines of migration to those of 1880, which being easterly and north-easterly have had the contrary effect of spreading out the migration again, or at least has not deflected it to the same extent; and also, the effect of causing birds to migrate at greater elevations, and, where the gales have been most severe, to bear them away above the range of vision and carry vast numbers out to sea, until, weary and exhausted, they have ceased to be able to guide themselves, and again, involuntarily, lowered, to be picked up senseless and stunned on board the ships, or to perish in thousands in the ocean. And lastly we have hinted at the wideness of the migratory waves depending upon the pressure at the starting-points, or upon the larger north and south area occupied in the breeding-season of 1880, besides some other minor details.