464 Roosevelt Wild Life .liinals 



Habitat. Judging from the conditions under whicii the twelve Iowa Darters 

 in our collection were taken, the fish is more of a lake than a stream fish, for none 

 was taken in streams except right at the mouths where lake conditions were an 

 influence; and they seem to prefer sandy bottom and to tolerate areas with con- 

 siderable vegetation. 



Hankinson ('16, pp. 125, 131-136, 151) found the Iowa Darters common in 

 small lakes and sluggish streams in the marshes along Lake Superior in the \\'hite- 

 fish Point Region of Michigan. None was found in Lake Superior, although their 

 habitats were freely connected with it, and they were found in quiet beach pools 

 close to it. They seemed to have strong preference for muddy bottoms of bays 

 and other places where the water was seldom disturbed. Many of them could be 

 seen here resting or moving slowly, leaving little trails behind them. At Walnut 

 Lake, Hankinson ('08, p. 216) found Iowa Darters rather common in shallow 

 water, in spring. In early April, shortly after the ice left the lake, these fish were 

 especially common where a marsh bordered the lake, being found among the 

 sedge roots there. After July i, none was found on the shoals. They evidently 

 go to the deeper water in late summer, in Walnut Lake. 



Jaffa ('17, p. yz), in writing of the habitat of this fish in Colorado, says: 

 "The darters were especially fond of pools where the bottom of the stream was 

 covered with a heavy slime and masses of rotting vegetation, which had to be 

 removed before the fish could be captured. When disturbed, the darters, which 

 could be seen resting on top of this slime, burrowed into the soft debris by a 

 series of quick movements of the pectoral and ventral fins. This preference for 

 the deep pools at this time seemed to be correlated with the breeding activities of 

 this species, as it was found usually under pebbles in swiftly running water and in 

 shallow riffies during the fall, winter and early spring." Ellis ('14, p. 109) re- 

 marks on the hardiness of this species, since it has been taken farther north and 

 west than any other darter and at the same time as far south as Arkansas. 



Evermann and Cox ('96, p. 421) say: "This species is pre-eminently an in- 

 habitant of small lakes, ponds, isolated overflow pools along river courses, and 

 of the sluggish, grassy creeks of the prairie region. Wherever w-e found a small 

 pond or slowly flowing stream with plenty of aquatic vegetation and a more or 

 less muddy bottom, there we found this little darter in larger numbers." 



Food. Six Colorado specimens were studied by Ellis ('14, p. 109). These 

 had been eating caddice fly larvae, Chironomus larvae, gastropods, annelids, and 

 entomostracans. Mosquito larvae also are eaten to some extent by this species 

 (Evermann and Clark, '20, p. 302). The food of twenty-eight Iowa Darters 

 from Lake Nipigon in Ontario is recorded by Clemens ('24, p. 144), with detailed 

 identifications of most food objects found. Chironomidae formed 30% of the fond. 

 and other aquatic insects were present in about the same amount. Small mussels 

 (Spliacriidac) constituted 11% of the food. Pearse ('18, p. 259) gives a sum- 

 mary of the food of five Iowa Darters from Wisconsin Lakes, as follows : chirono- 

 mid larvae, 21%; beetle larvae, 16%; amphipods, 58%; snails, 3%; oligochaete 

 worms. 1.6%; debris, .4%. 



Distribution Records. One Iowa Darter was taken in each of the following 

 collections, except No. 522, in which fniu- were taken. .All were caught between 



