52 
Though Gulls are essentially sea birds they are at times found at 
considerable distances from large bodies of water and flocks often follow 
the prairie ploughman to search for insects in the newly turned furrows. 
They feed from the surface of the water, seldom diving, or glean from the 
shores, beaches, or fields. 
Economic Status. Gulls eat any form of animal matter, fish, crusta- 
ceans, molluscs, insects, offal, and — -when opportunity offers — young birds 
and mice. 
The amount of fish they consume is relatively unimportant, as it is 
usually only very abundant small species occurring in great schools that 
attract their attention. They are not patient fishers like Herons, content 
to stalk their prey and take one fish at a time, but want them in abundance 
so that they can gulp them in quantities. They search low tidal shores 
for crabs and other shell-fish, showing considerable ingenuity in breaking 
the hard shells and extracting the contents, in many cases carrying them 
in the air and dropping them on the hard ground and rocks to shatter 
them. The food supply from these sources is economically insignificant. 
Gulls annually dispose of vast quantities of garbage and offal in the harbours 
and waterways and hence are beneficial scavengers. On the British Col- 
umbia coast they frequent the salmon rivers and gorge themselves on the 
spent and dying salmon. (The western salmon, unlike those of the east, 
after completing their mission of procreation die by thousands in the streams.) 
Undoubtedly at times some species destroy salmon eggs, but, as most of 
these are laid at the heads of streams rather than at the mouths where 
the greatest number of gulls congregate, their opportunity for serious 
damage is not great, except under exceptional circumstances or on short 
streams where the spawning grounds are within easy reach of the coast. 
Another charge against them is their egg-stealing proclivities when in 
the vicinity of rookeries of other species such as Murres and Cormorants, 
nor do they confine themselves to eggs alone, helpless unguarded young 
birds being equally welcome to them. It is apparent that when Gulls attack 
economically valuable species, objection may be taken to too great numbers 
of them, but their normal activities in this direction can as a rule be dis- 
regarded. 
Gulls also frequent agricultural land for insect food. Indeed, some 
species are characteristic of the broad inland prairies. At times Gulls 
have been instrumental in stopping small mammal and grasshopper plagues 
and the Mormons of Utah have erected a monument to Gulls, that appeared 
at an opportune moment and destroyed the crickets that were ravaging 
the fields and producing famine. Gulls must be considered, therefore, as 
beneficial on the whole, and should be protected, although they do some- 
times destroy eggs, young birds, and fish. 
39. Ivory Gull. Pagophila alba. L, 16-19. Entirely pure white when adult. 
Juvenile with slight grey clouding in front of eyes, and sparse, sharply-defined, dark feather 
edges and flecks on the larger feathers. 
Distinctions. The only absolutely pure white Gull with black legs. The young Glau- 
cous Gull is not only a larger bird, but, though nearly white, is always slightly clouded with 
brownish ash, and with legs brown horn colour to flesh pink. 
Field Marks. Too rare to be recorded on sight. 
Distribution. The Arctic seas, more common on the east than the west coast. One 
specimen has been taken in Manitoba, near the big lakes, and other individuals in the 
Cassiar and Okanagan districts in British Columbia. 
Too rare except in the far north to be further mentioned. 
