While standing in the Ross Street parking lot a few Saturdays ago, I was not expecting to see a real-life wildlife thriller unfold in the sky above me.
The drama started with a frantic series of osprey distress calls coming from the direction of the old railway crossing at Marine Drive. I knew this was the site of an active osprey nest containing at least one tiny baby. As I looked up from the busy Saturday farm market, a screaming osprey flew into view from the direction of the nest and sailed right over my head.
At first I was puzzled, I couldn’t see what was causing the alarm. Then looking up, way up, I spotted a high-flying bald eagle slowly patrolling through the airspace above the osprey nest.
As the eagle flew lower, the still-screaming adult osprey strained to gain altitude. Then another osprey appeared on the scene. It landed at the nest containing the helpless nestling. Most likely it was the screaming osprey’s mate responding to a call for help.
Gaining the advantage of superior altitude, the high-flying osprey took a position above the eagle and began a series of plunge-dives aimed directly at the would be nest-robber. While I have seen ospreys dive for fish countless times, this attack on an eagle was a first for me. Eagles are much bigger birds than ospreys, about three times their body weight, so initiating an aerial duel with an eagle is an extreme measure.
At the last moment before the plunging osprey made contact, the eagle flipped over on its back while brandishing its bright yellow feet equipped with two sets of formidable claws. Instantly the osprey aborted the dive and pulled upward in the sky. Again and again, the still-screaming osprey dove at the eagle and each time the eagle countered by rolling upside-down with readied talons. Mesmerized, I lost count of the attacks and responses but eventually the eagle set its flight path away from the nest and the defending osprey joined its family at the nest.
Perhaps because I was sensitized to pay more attention to screaming ospreys, a few days later I saw similar osprey-eagle encounter at another osprey nest along the Trans-Canada Highway near Centenoka Mall. Again, the parent’s high-risk aerial defence maneuvers appeared to save the baby ospreys.
While fledgling ospreys may be infrequent meals for eagles, stealing fish from ospreys is an everyday occurrence often seen from the wharf. If you notice an osprey over the lake follow with your eyes as it hunts. If the bird starts to hover, get ready to see it plummet into the lake, and then fly up hastily carrying a fish towards shore. Keep watching! Quite often, an eagle also is tracking the successful osprey and may give chase with the hope of forcing the osprey to drop its catch. If this tactic is successful, the eagle then circles back to pluck the fish from the water – an easy meal. Scientists have a colourful word for this behaviour – kleptoparasitism – routinely stealing food from another species.
Actual predation by bald eagles on adult ospreys appears to be an unusual event occasionally resulting from these risky encounters.
Two days after watching the Marine Park osprey successfully defend its young, I stopped by the Nature House to a look at the nest through a spotting scope. I was relieved to see the baby osprey still standing and protected from the blistering mid-day sun by its parent’s outspread wings.
While bird-watching often includes making daily lists of species seen or heard, looking for interesting bird behaviours offers limitless opportunity to see birds in new ways here in the Shuswap.
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