14 DAY TRIAL // You may think that only human males know when an offspring is not theirs (even if in practice, many do not grow their own children and this unwittingly...).
It is known that in many mammals, when a male takes over a group of females, first he kills the offspring which of course, does not carry his genes (examples are lions, tigers or gorillas).
Now, a shocking case proves this is also true with birds.
And even in a more refined way.
British ornithologists observed the case of an osprey (a fish eating bird of prey) male that returning to nesting during the 3,000 mi (5,000 km) spring migration (from West Africa to Scotland), when he found his long-term female partner incubating the eggs of his Arch-rival, did what humans would do.
The behavior was seen at the Loch Garten Osprey Centre in the Highlands.
The right male, baptized Henry, arrived 12 days later and by the time he arrived his female EJ had already laid two eggs to another male called VS.
Henry kicked off the nest, the eggs and, even more surprisingly, also the two more replacing eggs the female laid, which of course, were not his.
"Ospreys had spent summers at the reserve since 1958. EJ has a good breeding record, but VS is known to be something of a rogue having disrupted breeding at the Loch Garten nest site in recent years, two-timing EJ with a female of his own at a nest of his own elsewhere in Strathspey. Secretly, well not so secretly actually, we were hoping that Henry - EJ's regular mate - would return swiftly, drive VS from our nest and pair up with her himself. He is a much more reliable male osprey, a good provider of fish and something of a hero really." said Richard Thaxton, site manager.
When Henry arrived at the loch, VS was absent, and he landed close to the nest beside EJ (in many bird species, the males are not faithful to the female, but to the nest, like in storks and birds of prey).
"A packed house at the osprey center held their collective breath and watched in horror as our worse fears were realized. Henry, on seeing the two eggs in the nest-cup, deftly kicked one egg right out of the nest to smash below the nest and the other was kicked too - lodging precariously on the rim of the nest. All who witnessed this were completely stunned by what they saw and my new staff team are completed gutted by this." said Thaxton.