As has already been remarked, when nearing their destination migrating birds descend, though still many miles from land. Should a gale be raging they fly so low that they barely top the waves. And this, apparently, to escape, so far as is possible, the force of the wind. Larks, starlings, thrushes, and other small birds, can sometimes be seen during daylight crossing the North Sea in their thousands. At such times many will often afford themselves a brief rest in the rigging of ships, homeward bound, but the main host hurry on. The beautiful golden crested wren, our smallest British migrant, is one of these. A glance at our charming coloured plate will show at once that the wing is not that of a bird of strong flight. There is no more interesting experience to the bird-lover than that of watching the tired travellers drop earthwards, as they leave the dreadful sea behind them. With all birds yet retaining the power of flight there is always a liberal "margin of safety" in regard to the wing area. That is to say this is always in excess of the minimum area necessary to make flight possible. This much, indeed, is manifest from the fact that the eagle can bear off a victim equalling himself in weight. Should he miscalculate, he can always drop his burden, or lessen its weight by eating part of it on the spot. Not so the osprey, or the sea-eagle, which have been known to plunge down and drive their talons into fishes too large to be raised. Unable to release their grip, death, by drowning, has inevitably followed. Sometimes the burden is a passenger, instead of a victim. One of the most striking of the coloured plates in this volume is that of a woodcock carrying one of its nestlings to a distant feeding place. This habit is well known. It is not often that the necessity arises, but there are occasions where suitable nesting and feeding grounds cannot be found together, or when, as during prolonged drought, the normal feeding area dries up. Then, instinctively, the parent will surmount the dangers of starvation for their offspring, by conveying them to a land of plenty, returning again to the shelter of the wood as soon as the meal is over. The weight of a newly-hatched nestling, it is true, could scarcely be called a "burden." But they are carried about thus until they are strong enough to perform the journey for themselves. Thus, then, towards the end of the nursing period the weight to be carried is by no means a light one.