April, 1922. 



The Canadian Field-Naturalist 



67 



ed through a diet of grasshoppers, and I am of 

 the opinion that without the insect's presence, the 

 country would be deprived to a large extent of 

 one of its most pleasing songsters. 



The part played by gulls in reducing grass- 

 hopper outbreaks is well known, but the farmers 

 of Manitoba never witnessed so direct an example 

 of this value until the last two years, particularly 

 during the summer of 1921. 



In Southwest Manitoba there are two breeding 

 sites for Franklin's Gull, namely Whitewater and 

 Oak Lake. The exact number of breeding birds 

 that nest in these places is unknown to me but I 

 judge there are at least a thousand, possibly far 

 more. At all events the number present in July 

 aggregated fully 10,000. 



Franklin's Gull is rapidly becoming recognized 

 as an associate of the farmer and it is essentially 

 a follower of the ploughman. What an inspiring 

 sight it is to see four or five thousand of these 

 birds moving gracefully over the cultivated areas, 

 at times almost brushing the ploughman with 

 their wings, but on all occasions keenly intent 

 upon gathering up the insects driven from cover. 

 Having obtained enough they rest a while upon 

 the fields or perchance move off to some nearby 

 water, but they are soon back again industriously 

 gathering in the harvest of hoppers. So highly 

 are these birds valued that I have known farmers 

 to leave the insect extermination to them alone, 

 rather than to apply the poisoned bait which is 

 known to be effective. Nor did the birds fail to 

 live up to the farmer's expectations. 



The Upland Plover is one of the few of its kind 

 that adorn our prairies. It is a beautiful bird and 

 was once quite abundant. Cultivation and per- 

 secution have reduced its numbers much, but its 

 habits remain the same. It is still a grasshopper 

 feeder, perhaps more so than any other bird. 



Crows are of a type that turn anything to 

 advantage and there is very little that comes amiss 

 to them. Grasshoppers have always formed an 

 important part of their diet, but during the recent 

 outbreak they seem to have become particularly 

 wise to the hopper's habits. It is easy enough for 

 them to pick the insects off stooks of grain or 

 hay cocks, but when it comes to discovering the 

 breeding grounds and digging up the eggs, we 

 must admit that the crow has displayed a wisdom 

 shown by few other birds. That the crow has 

 numerous vices, from our point of view, every one 

 knows, but it has won many friends in Manitoba 

 during the last three years by its grasshopper- 

 devouring habits. Several incipient outbreaks of 

 the insect have been checked by the crow's ac- 

 tivities, while in some cases sodded areas heavily 

 impregnated with eggs have been freed of them 

 by these birds. 



Nearly all ground-feeding birds devour grass- 

 hoppers when chance offers but we cannot possibly 

 enumerate them here. Sufficient to say that in 

 aggregate they must account for enormous num- 

 bers of the insects during the summer months. 



Mammals are not generally thought of as insect 

 destroyers, but there are several, nevertheless, 

 that relish them as food. Skunks are largely 

 insectivorous and among the insects eaten are 

 numerous grasshoppers. Badgers, weasels, pocket 

 mice, shrews and even the obnoxious gopher all 

 aid in reducing them. Nor should we conclude 

 this list without including certain snakes, toads 

 and frogs. 



The dependence of one creature upon another 

 provides a problem that is greatly involved in 

 its ramifications. Let us take for example the 

 case of the crow. When grasshoppers are abund- 

 ant, these insects unquestionably form a staple 

 diet for the bird, and since this type of food is 

 ample the crow would naturally be less active 

 in its search for birds' eggs and nestlings. For 

 this reason there would be an increase in other 

 birds indirectly due to grasshoppers. To carry 

 this to an extreme it might be pointed out that 

 crows usually destroy numerous rodents such as 

 rabbits and mice, but in grasshopper years less 

 would be taken than when the insects were 

 scarce. This would pro\ade an increase of ro- 

 dents. The increase of rodents would provide 

 additional food for carnivorous animals such as 

 wolves and lynxes, and, since the smaller game are 

 more easily procured than the large kinds, the 

 result would be the preservation of big game due 

 indirectly to the prevalence of grasshoppers. 



I do not wish to infer that grasshoppers are the 

 only factors in providing for a perpetuation of 

 certain wild birds, but they are one of the most 

 important in their season, just as cutworms are 

 to horned larks in early June. Most insects are 

 only present, in numbers, for a limited period of 

 the summer, while grasshoppers are in abundance 

 from June to October. Some, indeed, winter as 

 nymphs and they are therefore among the first 

 insects available for food in spring and the last in 

 autumn. 



What would birds do without grasshoppers? 



What would grasshoppers do if there -were no 

 birds? We leave the reader to answer these 

 questions. 



Quite unconscious of the problems its presence 

 involves, our grasshopper pursues the course 

 alloted to it by nature. Of the 25 or more that 

 emerge from a sac of eggs one may die in infancy 

 dragged off by an ant. Another is attacked by 

 disease, forced up a stem by an uncontrollable 

 impulse, where it dries and bursts into dust, the 

 deadly spores being scattered broadcast upon its 



