drop-off

東北と関東地方ではクマの目撃件数が急激に上昇しているという報道です。
drop-offはPVのdrop offからきた名詞です。「急激な低下，下降」を意味します。単にdropというよりも，offがあることによって急激に落ち込んだ様子が伝わります。記事では見出しのspike（「急激に上昇する」）と対になって使われています。（UG）

Bear sightings spike in Japan's northeast

Bear sightings in the Tohoku and northern Kanto regions have risen sharply this year, due possibly to a lack of food or even territories widened by a drop-off in radiation-scared human visitors to the mountains.

On June 25, what is thought to be an Asian black bear appeared on the grounds of Tozawa Elementary School in Tozawa, Yamagata Prefecture, coming around 70 meters from 14 first-graders outside for gym class. The students were evacuated to a building across the street and there were no injuries. According to Vice Principal Hiroyuki Takahashi, 55, the bear was around 120 cm long and appeared to be excited, scratching the school building with its claws and hitting the glass doors at the entrance. The bear jumped on the hood of a school employee's car and broke a mirror before running back to the mountains.

In another incident on the morning of April 28 in Miyako, Iwate Prefecture, a 56-year-old man working in a field was seriously injured when a bear bit him on the legs and head. In Hirosaki, Aomori Prefecture, in the early morning of June 14, a 70-year-old man collecting bamboo shoots was slightly injured when a bear with a cub scratched him in the face.

According to tallies by prefectural governments and police, May and June bear sightings in inhabited areas have risen sharply since the same time last year, with incidents jumping to 243 from 64 in Miyagi Prefecture, 154 from 133 in Akita Prefecture, 144 from 43 in Yamagata Prefecture, and 132 from 33 in Fukushima Prefecture.

Northern Kanto also saw a sharp increase, with sightings in Gunma Prefecture doubling, and 14 reports made to Tochigi Prefectural Police as against zero last year. Dozens of reports have also been made to municipalities in the prefecture.

http://mainichi.jp/english/english/newsselect/news/20120722p2a00m0na011000c.html