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Honda T.,Yamanashi Prefecture Agricultural Research Center
International Journal of Zoology | Year: 2015

Rice is often damaged by birds, especially sparrows, in Asia. Bird nets are sometimes used as countermeasures; however this approach is expensive and labor intensive. For this reason, farmers generally eschew bird nets, even though no alternative countermeasures are available. This study focused on exploiting the bird behavior of scanning for predators to reduce crop damage. When birds forage for seeds on the ground they often stop pecking and briefly raise their heads, apparently to scan for predators. Low visibility habitats increase scanning behavior and increased scanning behavior reduces habitat quality from the bird's perspective; therefore, this study tested the relationship between rice damage rate and visibility at the periphery of rice fields, where tree sparrows rest after feeding. Overall, low visibility reduced damage to rice. Because visibility was mainly affected by weeds, weed management techniques contribute to crop damage management. To reduce damage, weeding can be decreased; therefore, this technique is cost- and labor-efficient. © 2015 Takeshi Honda.

Honda T.,Yamanashi Prefecture Agricultural Research Center
Journal of Ethology | Year: 2012

Many techniques are used to deter birds from damaging crops, but almost all methods are impractical. Line techniques have some effectiveness and rarely result in habituation, but their mechanisms are not clear. Cost-effective and long-lasting damage control approaches are increasingly important, and thus an improved line technique that does not incur higher cost or additional labor is needed. To achieve this, this study used different colored lines (i. e., metallic wire-line and matte black wire-line) to test whether line color affects the deterrence of crows (Corvus spp.). The two colors differ in their ability to reflect the sun. Crows exhibited a higher risk of collision with the matte black wire-lines. Deterrence was also higher with matte black lines than metallic lines. Given these results, the author hypothesizes that lower visibility lines incur higher collision risk and thus have a greater deterrence effect on crows. © 2011 Japan Ethological Society and Springer.

Iijima H.,Yamanashi Forest Research Institute | Nagaike T.,Yamanashi Forest Research Institute | Honda T.,Yamanashi Prefecture Agricultural Research Center
Journal of Wildlife Management | Year: 2013

Deer population control is important in wildlife management, because overabundance of deer is a problem worldwide. For practical deer population control, deer population dynamics and the factors that influence them need to be evaluated in low-cost and time-efficient ways. However, in traditional methods of estimation, such as cohort analysis, large numbers of deer need to be caught for many years, and the ages of the deer must be determined. We estimated deer population dynamics by using a Bayesian state-space model with multiple deer abundance indices (seen deer per unit effort, pellet group count, and block count) and numbers of deer hunted and culled in Yamanashi Prefecture, central Japan. In the state process of our state-space model, latent deer abundance at year t in location m (Dt,m), with m being each cell of a grid mesh covering Yamanashi Prefecture, was assumed to decrease annually through hunting and culling, to increase with the population growth rate of each mesh (r m; which was determined from the percentages of forest, evergreen forest, and artificial grassland), and to fluctuate stochastically. In the observation process, Dt,m was assumed to be correlated with the deer abundance indices and a Gaussian white noise in the deer abundance indices. The estimated Dt,m was correlated with each deer abundance index, but the correlation coefficient was the greatest for pellet group density. The percentage of hunted and culled deer needed to reach 30% to reduce the annual growth rate (Dt,m/Dt-1,m). Increasing the percentage of artificial grassland increased rm. Our results showed that 1) deer abundance could be estimated by using only deer abundance indices in addition to population growth rate and the percentage of hunted and culled deer; and 2) preventing the intrusion of deer onto artificial grassland and intensive culling on artificial grassland were important to decrease deer abundance. © 2013 The Wildlife Society.

Honda T.,Yamanashi Prefecture Agricultural Research Center | Iijima H.,Yamanashi Forest Research Institute
Population Ecology | Year: 2016

Wildlife can cause serious crop damages, and factorial analyses focusing ecological aspects have been conducted to resolve this problem. However, ethological perspectives should also be considered. Individuals often show consistent biases in behaviour—so-called personality; e.g., boldness may cause to intrude into a farmland. Here, we hypothesized that boldness–shyness traits in wildlife could be managed through selective harvesting on the base of personality traits. We considered several scenarios involving the selective harvesting and fencing as means to prevent crop damage, and assessed their effects on the average boldness and population size using simulation models, assuming that bold individuals tend to enter farmlands, while shy ones prefer to stay in forests. The results showed that fencing and selective harvesting in farmlands reduced both the average boldness and crop damages, while harvesting in forests caused the increase of the both. Those results came from the selective harvesting and fencing on the base of personality traits, and indicate that not only population ecology but also an ethological approach is needed for wildlife management. © 2016 The Society of Population Ecology and Springer Japan

Honda T.,Yamanashi Prefecture Agricultural Research Center | Tsuboi J.-I.,Japan National Research Institute of Fisheries And Environment of Inland Sea | Kuwata H.,Yamanashi Prefecture Agricultural Research Center
International Journal of Zoology | Year: 2015

We examined feeding behavior by visually blocking fruit to establish a new theory of bird damage management for agricultural practices. Partly or fully invisible clusters of grapes were fixed on a perch. The birds selectively pecked the clearly visible part of the half-visible bag at a pecking count rate of 0.94-1.00 (95% CI). Half-visible bags allowed the birds to look inside like a skirt and detect the initially hidden portions of grapes, which were covered with opaque white bags. However, very few birds pecked at the white bags that were partially covering the grapes. That is, very few birds attempted to eat covered but easily detectable fruits. Only five birds gravitated toward the grapes in the completely covered nontranslucent bags, but they never pecked at them. Our results show that visual blocking could be a promising new technique to prevent bird damage. © 2015 Takeshi Honda et al.

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