December 12th   Leave a comment

I was walking across the stubble field next to Pinkerton, heading down to Saucehope, and noticing that the skylarks were flushing practically at my feet as if it was very cold. It’s been a bit chilly but nothing like the frosty weather that usually makes skylarks act like this, when they can’t afford to waste any energy flying away needlessly. Then the real reason for their skulky behaviour appeared. A female merlin taking off from a fence post at the edge of the field. It headed off to the airfield but it must just have been hunting over the stubble field. Skylarks have two strategies when being hunted by a merlin. Those that are fit, or with plenty of energy to spare, can afford to fly away when a merlin appears. They take off and fly straight up, keeping above the merlin. Sometimes they even sing to signal that they are able to sustain a long chase if the merlin decides to press home its attack – but this is usually enough to put the merlin off: it doesn’t want to waste time chasing if its prey is strong enough to escape. A great strategy for a fit skylark, but any less fit bird that flies up less strongly and without singing boldly is immediately identified as a loser. So, the second skylark strategy is to stay put when a merlin appears – they freeze and rely on their camouflage. It is very effective – try spotting a skylark in a stubble field before it moves – although sometimes merlins land and start hopping around looking for the birds in hiding. And this then all perhaps explains why I only saw a few skylarks in the field, that flew up as I nearly stepped on them and then landed only a few meters away. All the fitter ones had already flown off leaving only the skulkers. Predators create these effects all the time – changing the behaviour and distribution of their prey without having to kill anything. I changed the distribution of the merlin today as it avoided me, making the stubble field safer for the remaining skylarks, but I made the airfield more dangerous when the merlin moved over there. 

Skylark – hide
Merlin – seek

Posted December 12, 2019 by wildcrail in Sightings

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