The memory of birds is well developed. Many of them remember the very grove or meadow, and even the very knot-hole or bush, in which they built their nest the season before, although in the meantime they have journeyed over lands and seas and sojourned thousands of miles away. Every year, for several seasons past, in late summer and early fall, after the nesting-time is over and the young ones are all grown, the purple martins have gathered in large numbers about the Field Columbian Museum, in Jackson Park, Chicago. They stay here for a few weeks, foraging the surrounding air for insects by day, and sleeping on the great dome of the Museum by night, finally flying away to be seen no more in such numbers till next year. These birds, many of them anyway, must remember from one year to another this annual assembly here by the big waters, else why would they come together at this particular spot from all over the country? I have no doubt that some of them, having sojourned here year after year for some time, remember well the great ugly building where they meet, and are more or less familiar with the surrounding locality from having searched it so often. I wonder what led to the establishing of the custom in the first place. Customs do not fall from the skies. And what advantage is there in the practice? What are they up to as they chirp and wheel in the air, and flutter up the slopes and sail down again, and perch on the pinnacles and twitter? Maybe it is a sort of Saratoga for them, where they all come together ostensibly to dip their bills in the blue waves, but where sons swell in their new feathers, and sly mammas find prospects for unmarketable misses. A parrot has been known to remember the voice of its mistress after an absence of a year and a half—a very remarkable feat even for the grey matter of a bird. A flock of geese mentioned by Romanes showed their knowledge of the arrival of market-day, which came every two weeks, by assembling regularly on such days, early in the morning, in front of the town inn where the market was held, to pick up the corn. They never came on the wrong day; and on one occasion, when the market was omitted on account of a holiday, here came the unfailing fowls cackling and shouting as usual in merry anticipation of their fortnightly feast, but ignorant of the national necessities which had doomed them to be disappointed.[6] Parrots remember and call for their absent friends, and mumble phrases in their dreams which have been taught to them. These gifted birds learn long poems by heart, and sing songs with considerable art. A parrot belonging to the canon of the Cathedral of Salzburg was given instruction regularly two hours every day for ten years, from 1830 to 1840. The bird became very proficient in speech and exceedingly intelligent. It took part in conversations, whistled tunes, and was able to sing a number of popular songs, among them an entire aria from Flotow’s opera of ‘Martha’.[7]