The kingfisher is the most common and universally distributed bird predator of fish in Michigan. Its principal migration routes are along the Great Lakes shores. Nesting territories are established along streams and lake shores; they are usually larger in the former than in the latter. The kingfisher is diurnal in its feeding with three peaks of activity–morning, afternoon, and early evening. First feeding of fledgelings is on insects; this food is followed by crayfish, then by fish. Fish eaten average about 2.3 inches in length and at fish hatcheries are mostly the species being propagated. On natural waters the food consists mostly of non‐food and non‐game fishes and crayfish. Predation pressure varies with season and within season according to weather, nest distribution, and environmental suitabliity of waters for feeding activity. Because of their feeding proclivities, it is undesirable to have kingfishers about fish hatcheries and rearing stations. At present, general control on natural waters is not biologically justified.
Two studies were conducted to evaluate the effects of a feed sweetener on nursery pig performance. In the first study, 360 pigs (PIC 800 x 1050; 6.22 ± 1.20 kg) were blocked by BW and pen location and assigned to 3 treatment groups: 1) Control; 2) 100 mg/kg feed sweetener; or 3) 200 mg/kg feed sweetener. There were 12 pens containing 10 pigs for each treatment. In the second study, 540 pigs (6.12 ± 0.39 kg) were blocked by BW and pen location and assigned to 3 treatment groups: 1) negative control; 2) 100 mg/kg feed sweetener; or 3) 0.5% carob bean. There were 18 pens containing 10 pigs per pen for each treatment. A 3-phase feeding program was used, and diets were fed for 6 wk in both studies. In study 1, ADFI, ADG, and gain:feed were increased (P < 0.05) during Phase 1 for pigs fed diets with 100 mg/kg or 200 mg/kg sweetener. Phase 2 ADFI and ADG were increased (P < 0.05) in pigs fed 100 mg/kg sweetener when compared to the control. Increased BW (P < 0.05) were observed on D 7, 14 and 21 for animals fed 100 mg/kg or 200 mg/kg sweetener. The mortality rate was decreased (P < 0.05) in the group of animals fed 100 mg/kg sweetener compared to the control. In study 2, there was no effect of sweetener or carob bean on growth performance, feed intake or gain:feed. However, mortality rate was decreased (P < 0.05) in pigs fed the sweetener compared to pigs fed carob bean. In conclusion, the feed sweetener improved early nursery performance in one study and had no effect in another study. Mortality was decreased by supplementation with 100 mg/kg sweetener when compared to a negative control in one study and compared pigs fed carob bean in the second study. Further research is needed to explore differences observed between studies to optimize feed sweetener usage strategy.
Studies of fish predators, with particular reference to those affecting inland lake and stream habitats, have been in progress by the Institute for Fisheries Research since 1930. The methods of study have included stomach examinations, field work to determine predator abundance in relation to fish abundance, and examination of
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