See gull take on eagle in mid-air piggyback attack
Gulls are utterly fearless, as shown by this remarkable image of a white-tailed eagle under attack. Herring gulls dive-bomb predatory birds at a steep angle from above and behind, as they make a piercing shriek – “kaiow!”. The attacks typically occur when the gulls are defending themselves and are most frequently seen during the breeding…
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Roger Highfield - New Scientist