In the economy of birds, the most important labours are those of nest-building and incubation; and owing to the wintriness of the spring, we were quite prepared this morning to find matters in a decidedly backward state throughout the length and breadth of bird-land, wherever we might wander. We were not, however, prepared to find things in anything like the sad plight in which we actually found them; for in no district of the remotest Highlands, we venture to say, are the agricultural labours proper to man at this season so backward as are their own proper labours this year amongst our native wild-birds. Usually at this date nine-tenths of our birds have already completed the labours of nidification, and with some species even incubation is far advanced, if not actually completed. The results of our morning's ornithological ramble may be very briefly stated. Of thirteen nests discovered, four only contained eggs, and even of these four only one had its proper complement, that of a song-thrush, namely, which contained five bonny blue eggs, spotted with black at the larger end, a number rarely, if ever, exceeded. In a merle or blackbird's nest there were only two eggs, instead of the usual complement of four or five. A chaffinch's nest had only one egg, whereas four is the proper number; while in the nest of a greenfinch, there was also only one egg instead of five, and that one, from certain signs known only to the initiated, we decided had only been laid yesterday, or even early this morning--perhaps shortly before our visit. Of the remaining nests, a few were fairly completed, and ready for their egg treasures at any time, but the greater number were only partially finished, and in their unfinished state had suffered so much from sleet and wind and rain, that we much doubt if their builders will have anything more to do with them, for it is a curious fact, that with such rare exceptions as only serve to accentuate and emphasise the rule, all birds prefer building a new nest from the very foundation to occupying an old one, or making the slightest repairs on one that has met with any serious injury. And this, too, you will please observe--a bird never improves in his architecture and never declines. He builds to-day neither better nor worse than did his ancestors a thousand or five thousand years ago. The sense or instinct that taught him to build of certain materials and of a certain form, long before Homer was born or Troy was besieged, is the same sense or instinct still. Nothing added; nothing subtracted. From all we have seen, we should say that the annual addition to bird life in our country will be considerably smaller than the average. Even first broods will be so late that second hatching is out of the question. Bird-song, however, will last longer into the summer, and begin again earlier in autumn than in ordinary seasons.