322 . Animal Life 
simply flapping, or by flapping and gliding 
alternately. The Duck is an example of the 
former method, and the Gannet and Partridge 
of the latter. But whereas the partridge’s flight 
is quick and violent—whiz alternating with 
skim—the gannet’s strokes are slow and easily 
counted. he partridge, like other short-winged 
birds, has to make up in the rapidity of its 
strokes what it lacks in their efficacy; it and 
Fig. 11. Kestrel hovering. 
other such birds thus acquire great 
speed, but they are soon exhausted, 
and may be even ridden down. 
Some short-winged species, such 
as the Guillemot, do not even skim, 
but keep on a contimuous quick 
flutter from first to last. Species 
with noticeably large wings and 
light bodies can do much as they 
like in the air; but among these 
there will be noticed remarkab le 
differences according to the form of the wings, a species with large rounded wings like 
the Lapwing being not fast, but clever at sudden evolutions, while a sharp-winged bird 
with long wings easily attains to great speed, but cannot rise or shift so readily. 
Thus the sharp-winged Falcon finds the Heron, with its large hollow wings, rise 
much more easily, and in order to get above it, has to bring into play all its strength 
and speed, tearing round in vast circles, in the centre of which the heron is making 
small rings. 
In the same family the smaller species will move their wings much more quickly 
than the larger. This is well seen in comparing the flight of a Duck with that of a 
Goose, or that of a Partridge with that of a Peacock. The flight of the last bird, by 
the way, has no intervals of cessation, and with its comparatively slow strokes seems 
fairly easy; but the peacock is really a poor flyer, and cannot “stay” long, even in 
the wild state. 
On the other hand the Swan, which rises with great difficulty, is, when fairly 
launched, a very swift flyer, cwing to its great weight and muscular power, and easily 
passes a Duck at full speed. 
A very large number of birds, nearly always of small size, have a peculiar undulating 
flight, since after a few quick strokes they close their wings and drop, again rising with 
another flutter; this mode is particularly characteristic of Passerine birds, though not 
found in large species like the Crows, nor in some smaller ones. It is probably a 
means adopted to gain impetus for a light weight. The largest birds which practise it 
are some of the Woodpeckers, such as our common green species, which is shown at 
the instant of closing its wings (Fig. 12). The mention of this group shows that the 
practice is not confined to Passerines, but it never occurs among groups which live on 
the ground or swim, and some tree-birds never use ib; thus the Parrots fly with steady 
repeated strokes like Waterfowl. 
Some birds have a very eccentric flight; thus, the Jay, although short-winged 
like the Magpie, does not travel by rapid flaps like that bird, but with slow, measured 
Fig. 10. Heron flying. 
