item of food, composing nearly 43 percent of the total. Other fishes taken 

 fx-eqaently included yellow perch, bullheads, sunfish, carp, and flounders, 

 but small numbers of tautog,, tomcod, and gobies also v;ere found. 



Mergansers •■■ . , . . ; 



To many hunters and fishermen mergansers are all just "fish ducks" and 

 therefore worthless or of value only as a target for practice shooting. 

 Nevertheless, the males are an'iong the most beautiful of all North American 

 waterfovjl, and x.'ith the exception of one species, the group can rarely be 

 considered unduly destructive to valuable fishes. There are three distinct 

 species of mergansers in this country, one of vjhich — the American — sometimes 

 causes noticeable damage. The red-breasted merganser closely resem.bles it, 

 but is rarely found on trout vjaters and feeds much, less, on -game fish. The- 

 little fish duck, or hooded merganser, though known to f eed ;.rather freely .on 

 small '.and unimportant fishes, also consumes considerable qua.ntities of 

 crustaceans and insects. So far as kno^vvn, all three species of mergansers, 

 within their range of diet, .feed on the species that are most available'. 

 Consequently,^ the more abundant and sluggish' varieites constitute ,the-major 

 items of food, Vi/hile able to capture svjifter fishes,, these birds follovj the 

 course of least resistance and obtain thei.r food with the minimum exp-enditure 

 of effort. The i\merican merg&nsor is occasionally abundant on the smaller 

 trout streams but is more comraon on rivers and open, lalces; the red-breasted 

 is most plentiful along the coast; v-'hile the American is more common inland 

 and, therefore, is the form most vigorously condemned. On the larger bodies 

 O'f water these birds usually are not destructive. 



A tabulation of the contents of ISO stor.i'dchs of th§ red-breasted 

 merganser revealed that 34,23 percerit of the food was composed of fishes 

 that have no commercial value, chiefly minnoxvs, killifishes, and sticklebacl^s. 

 Low-grade commercial fishes, principally carp and suckers, formed 3 percent. 

 Valuable -commercial species and popular game or pan fishes made up 14.38 

 percent, but did net include a single trout. Unidentified fragments of fish 

 composed 25.08 percent of the total contents, and miscellaneous items, chiefly 

 cravifishes and shrimps, made up £3.31 percent. 



The American merganser is known occasionally to make particularly 

 serious ir^roads on the trout supply when concentrated on narrow sections of 

 trout stream.s at times v;hen the surface of larger bodies of water is frozen 

 solid. Tabulation of the stomach contents of 107 of these fish ducks, m.any 

 of which 'ivere collected on Canadian and Michigan trout streams, revealed that 

 27 contained trout. Fishes having no comanorcial value, including considerable 

 numbers of destructive spaxvn-eating species (chiefly mi.nnovjs, sticklebacks, 

 sculpins, darters, and killifishes), made up 33.27 percent of the food, while 

 valuable commercial or game fishes including trout, and popular pan fishes 

 fonaed 32. 7S percent, Lowr-grade commercial fishes (chiefly suckers and carp) 

 constituted 7.52 percent, and unidentified fish fragments made .up 7.42 p.ercent, 

 Miscellaneous items, composed principally of cravjfishes, frogs, insects, and 

 vegetable debris, formed the remainder. 



A-n examination of the contents of 138 hooded merganser stomachs revealed 

 that this duck does not eat nearly so large a proportion of fish as do the 

 other two fish ducks. Fishes of little commercial or sporting value formed 



- 11-. 



