NORIO TOKITA

We investigated the intake and digestibility of different reed canarygrass (RCG) growth stages by sheep. RCG was cultivated in an experimental field and harvested at the first and second cuts at each pre-blooming stage. Feeding behavior was monitored on adult female sheep, fed 3 kg each of fresh RCG three times daily. While the crude protein content and dry matter digestibility of RCG were significantly higher in leaf than in stem tissue of both first and second cut in harvesting times, neutral and acid detergent fiber contents were higher in stem than in leaf. The dry matter intake of RCG at the second cut (296.1g) was significantly higher than at the first cut (214.1 g). The eating time for consumption of RCG on dry matter at the second cut (54.9 min) was shorter than at the first cut (69.4 min). Consequently, at the second cut, the rate of biting (54.6 bites/min) was lower than at the first cut (64.8 bites/min). Bite size, expressed as dry matter intake per bite, ranged from 0.05 g at first cut to 0.10 g at second cut.

To determine how fruit ripening influences fruit removal by birds, we investigated the relationships among fruit color, nutrition value, and avian fruit removal during the fruit ripening period of Prunus jamasakura. Fruit maturing process was divided into 4 phases on the basis of fruit color: green, green-red, red, and black. Green and green-red fruits were smaller, with lower sugar content (i.e., fructose, glucose, and sucrose) and energy levels than those of red and black fruits. Most of the fruits removed by birds were red and black fruits and birds especially preferred black fruits. Black fruits contained more sugars and energy than red fruits. Differences in sugar concentration and energy between them were approximately 4.6% and 0.4kJ, respectively. Gray starlings Sturnus cineraceus and brown-eared bulbuls Hypsipetes amaurotis were the predominant birds visits to the focal tree. The number of gray starling visiting the focal tree increased during the period of the bicolored display from the contrasting colors of ripe and unripe fruits. However, the number of brown-eared bulbul did not appear to change throughout the fruiting period. These results indicate that the bicolored display serves as an effective means of attracting birds; however the effect differed between bird species.