230 
CIIARADRIIFORMES 
grown grain waves in the wind, there is a constant procession from the 
breeding sloughs out over the farmland. Beating across the soft green 
fields, a flock of a hundred or more will pause, hover a moment, and then 
drop into them, sinking from sight — one, a few, or many at a time, in a 
little spot that makes the onlooker wonder that so many can find shelter 
and concealment in so small a space; but the sea of grain closes over them 
so that no sign is visible of the eager activity below. Presently a black 
wing is raised, a white body flashes in the sun; others follow, and for a 
moment there is a white outboiling that presently resolves itself into the 
flock, wing-borne, to again circle away over the many-acred field and repeat 
the performance. At times a number of such aggregations can be seen at 
once over a single field. The attraction is generally grasshoppers and the 
number of these insects that a few hundred gulls can devour on a long 
summer day, and day by day throughout the season, is an important factor 
in insect control. 
Again, in the evening, they may mount the upper air over or near lake 
shores and, high up, gleaming like jewels in the last rays of the setting sun 
while the ground below perhaps is lost in blue evening shadows, they weave 
intricate aerial patterns in pursuit of the “lake flies” that blow in smoke- 
like clouds about them. 
In the autumn they often unite with flocks of Bonaparte's Gull, form- 
ing incredible numbers, and drive up and down over the harvest fields, 
rising on whistling wings to pass over obstructions and again descending 
to barely a man’s height from the ground as they gather the insects from the 
air. What species forms their special pursuit at this time has not been 
definitely ascertained, but undoubtedly the great majority of their tiny 
prey are better placed in the crops of hordes of gulls than peaceably per- 
mitted to prepare for next season’s crops. 
Economic Status, On the whole, the western farmer probably has no 
more efficient friend than this little gull of tireless wing, and the indigna- 
tion of the community should be experienced by those who disturb their 
nesting or interfere with their security. In many localities, a swamp 
where these gulls breed is worth far more as insect insurance to the sur- 
rounding community than if it were drained and its small acreage brought 
under cultivation. A few hundred acres are an inappreciable addition to 
the sum total of productive land and may at times be bought at too high 
a price. Consideration should be given to this factor sometimes before 
the last bits of reclamation are undertaken. 
60. Bonaparte’s Gull, la mouette ou mauve de bonaparte. Larus Philadelphia . 
L, 14. Plate XXVIII A. 
Distinctions. East, central, and 
west. Likely to be confused only 
with Franklin's Gull and with it only 
in the Prairie Provinces. It can 
be distinguished from that species 
by its slightly lighter mantle and 
large amount of white on the wings 
(wrists and most of the primaries pure 
white instead of slate grey) (Figure 
33G, compare with Figure 335). The 
Figure 336 bill is black in all ages instead of 
Wing of Bonaparte’s Gull; scale, i. maroon and the feet vary with age 
and season from flesh-coloured to 
coral-red instead of from black to dull maroon. In both species the rosy suffusion of the 
underparts is evanescent and not always present, quickly fading to white after death and 
