We are investigating territorial defense behavior against intruders at the nesting site of a breeding pair of Peregrine Falcons.
- ハヤブサのつがいが巣営する場所でテリトリー侵入者への防衛行動を調べています。
Observation Date: 2026-03-09Weather: SunnyWind: NW 1m/STemperature: 1°C
2026/03/09(月) 晴れ 1℃ 北西1ｍ/ｓ
7:50 Start time 観察スタート
No Peregrine Falcons present at the start of observation.
- 開始時はハヤブサ不在
8:03 One Peregrine Falcon returned from the south and perched on a tree on the cliff about 120 m away, not carrying prey.
- 南から１羽が戻り。餌は持ってない。120ｍ先の崖上の木に留まった。
8:15 Flew out and headed north.
- 飛び出して北へ行った。
8:50 An Osprey entered the territory at 223 m altitude and began circling. Peregrine Falcons absent.
- ミサゴ侵入（上空223ｍ）旋回開始。この時ハヤブサ不在。
8:52 Peregrine Falcon returned. Detected at 893 m, rapidly approached and began circling. The Osprey retreated.
- ハヤブサ戻り。893ｍでハヤブサ確認後に急接近して旋回する。ミサゴは逃げる。
The Peregrine Falcon approached the Osprey and drove it away, but no calls or attacks were observed.
- ミサゴにも警戒、接近して追い払う行動を見せた。鳴いたり攻撃したりはしていない。
9:18 A Black Kite passed overhead at 296 m altitude. Peregrine Falcons absent.
- トビが上空296ｍを通過したが、ハヤブサは不在。
10:14 Osprey passed overhead at 120 m altitude (close). Peregrine Falcons absent.
- ミサゴが上空120ｍを通過（近い）したが、ハヤブサは不在。
10:38 Osprey passed overhead at 252 m altitude. Peregrine Falcons absent.
- ミサゴが上空252ｍを通過したが、ハヤブサは不在。
11:00 Observation ended.
- 観察終了
Summary（まとめ）
Peregrine Falcons were absent for much of the observation period today.
During that time, several Osprey intrusions and circling events were recorded.
Under normal conditions, Peregrine Falcons in this territory often show little response to the presence of Ospreys.
However, on this occasion, a Peregrine Falcon appeared from a higher altitude, rapidly approached, and began circling near the Osprey.
Although no direct attack was observed, the behavior appeared sufficient to drive the Osprey away.
The Osprey was observed folding its wings and increasing speed as it retreated.
Future observations will focus on collecting additional data on Osprey intrusions when Peregrine Falcons are already present within the territory.
- 今日はハヤブサの不在時間が多かった。その間にミサゴのテリトリー侵入、旋回が数回あった。普段ハヤブサはミサゴが侵入しても警戒しない行動をとっていたが、今日はミサゴのさらに上空から現れて急接近、威嚇とまではいかないものの旋回をしミサゴを追い払っていた。ミサゴが翼をたたみ速度を上げて逃げる姿が確認できた。次はハヤブサが居るときに侵入したパターンでデータを集めたい。
Today the Peregrine Falcon (detected at approximately 893 m) approached an Osprey (circling at about 223 m) from a much higher altitude, using a clear altitude advantage to assert aerial dominance.
The behavior appeared to function as a threat display rather than a direct attack.
The photograph shows the moment when both birds were circling at around 200 m altitude, with the Osprey retreating from the area.
A video recording would have captured the interaction more clearly.
- 今日のハヤブサ（893m）はミサゴ（223m）に対してさらに上空から接近し、高度優位を利用したアプローチを行った。これは直接攻撃ではなく、威嚇的な空域支配行動と考えられる。写真は両個体が上空約200m付近で旋回し、ミサゴが逃避する場面である。動画であればこの行動連鎖をより明確に示せたと思われる。
コメント