CALENDAR OF ORNITHOLOGY FOR 1849 . 
a feather, thereby bringing into view some other portion, and pro- 
ducing a different tint ; in others, the colour of the feather entirely 
changes. These variations take place more or less rapidly with 
the seasons ; but in some instances, the change is effected in a day 
or two, as in many of the plovers and sandpipers, some ducks, and 
the^ head of the black-headed gull, &c., so that exactness in the 
legislation of them should be observed. Some of our summer 
visitants assume their breeding dress after arrival here, while 
others are partially changed, as if the operation had commenced 
and was going on at the same time with the instinctive desire 
to migrate. And again, on the cessation of the duties of the 
male, does the brilliancy begin to fade, and the dark or rich con- 
trasted tints to blend into a plumage broken and worn, and then 
commencing to be renovated by a new moult — all these mutations 
are worthy to be noted, and can be easily done at the same time 
that other facts are registered. 
It is during this same important period that a great change 
periodically takes place in the song and voice of birds. Many 
species sit and utter their call from some selected spot, which is 
frequented day after day ; but others practise peculiar modes of 
flight, calling as they fly. The pleasing song of our warblers and 
thrushes, the call of the pigeons and cuckoo, are familiar examples 
of the first. The towering flight of the greenfinch, and the rise and 
tall of the pipits singing as they fly ; the drumming and flight of the 
snipe, and the shrill shaking whistle of the curlew, are examples of 
the combined exercise ; but in every species there is a change more 
or less marked, which will be easily seen and noted by a practised 
or willing observer. 
As previously mentioned, the following tables have been drawn 
out, as far as possible, for Great Britain generally ; at the same 
tame they may be in part inapplicable to several districts, and par- 
ticularly to the insular localities in the north, from which, however 
we would hope for returns; but in these, if there is a scarcity of 
wood, and a limit in the numbers of the land or arboreal species 
either migratory 0 r resident, the arrival and departure of the sea- 
owl to breed, those that surround the shores in winter, and those 
that return regularly to roost at night, will be of great interest. 
We have no account of a rock or island, narrow in extent, minutely 
rCSiUf t0 tbC dally and regn,ar habits of its occupants. 
