Tonight I just caught the end of Planet Earth II – the last one in the series, as it happens.  It was about how various species have adapted to life in the cities that humans have created.  I switched on at the bit with hyenas that coexist with humans in Harar, Ethiopia, and watched right through to the end with Hawksbill Turtles crossing the road in Barbados.

The trouble with the Hawksbill Turtles is that when they hatch (which is at night), they need to head towards the sea, like, right away.  And how do they find the sea?  They follow the big, bright light in the sky because that signifies the Moon’s reflection off of the sea.  Unfortunately for them, humans have developed technologies that really screw with the hatchlings’ sense of direction.  Towns on the shore are full of bright lights that outshine the Moon, and so the turtles head away from the sea and into the towns.  Of those that do make it to the sea, only 1 in 1000 will grow to adulthood.  The odds aren’t looking great for the Hawksbill Turtles.

But back to the ill-fated wanderers.  Off they go on their journey towards what they must think of as the bestest, brightest, mega-moon evaaaaarrrrrrrrrrr!  And there are many hazards on the way.  Some disorientated turtles fall prey to hungry shore crabs, some slip into storm drains and can’t get out, and others get run over on the busy roads.  I’m not sure what happens to any of them that survive this turtle-themed Tough Mudder, but given that they need to make it to the sea to survive, it doesn’t look great.

But it’s not all bad!  Conservationists on the beaches of Barbados go out at night to rescue lost turtles and plop them back in the sea, as illustrated in this video.

Yay!  The heart-warming responses to BBC Earth’s tweets about this are testament to the Awesome Feels this engenders in the viewing public.  This time I haven’t concealed names to protect the guilty, as everyone in this public Twitter exchange is remarkably well-behaved:

But I’m not sure if this is the correct thing to do.  Watching this, I was reminded of the results of a well-intentioned intervention by humans on the nesting behaviour of black robins.  My party-pooping-self dropped a Devil’s Advocacy bomb on the Twitter love-in:

not one to mince my words The article I linked to (link reproduced below also) described how researchers in New Zealand noticed that some black robin females would lay eggs around the rim of the nest, leaving them less likely to be properly incubated.  The contents of these eggs would die.  And so conservationists would push these eggs back towards the centre of the nest to give them a chance of survival.  It was a huge success; more black robins were born and survived as a result of their intervention.  However, there was a catch: the offspring arising from the intervention would be more likely to lay their eggs around the edge of the nest.  The conservationists had inadvertently retained a trait in the species that would have been bred out due to natural selection.

The Road To Extinction Is Paved With Good Intentions

I wonder if that could be happening here – are we killing the species with kindness?  I’m not a biologist, so my expertise in this area is rather limited.  But it sounds like a similar scenario. Can anyone advise? Leave me a comment below!


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