I have noticed that our backyard chickens squawk after they lay an egg. This seems like very inappropriate behaviour - why draw the attention of predators to this valuable, brand new piece of food?

Being the heaviest organism on the planet (ignoring anything that photosynthesises or any ridiculously big fungi), baring in mind it lives in water, a blue whale is a huge lump of a mammal and probably has the capacity to reach some speed if given a chance and could probably cause great distress to krill populations if it where to waste more energy painting on go faster stripes. What's the fastest a blue whale has ever been recorded? It has probably never felt the need to outrun a predator or to leap on unsuspecting krill, and isn't really built for speed and has never seen the point in chasing after...anything at all...except krill...and maybe to out compete males if it itself is a male. Theoretically how fast could a blue whale swim if it let it's metaphorical hair down?

Being the heaviest living organism on the planet (that doesn't photosynthesise or isn't a ridiculously big fungi) , baring in mind that it lives in water, what's the fastest a Blue whale has been recorded swimming? being a huge lump of a mammal, it has probably never felt the need to out run anything or take on random spurts of speed to leap on krill, nor is it built to race...much at all...except krill..and maybe other blue whales for a mate. but theoretically how fast could a Blue Whale be if it let it's metaphorical hair down? Thomas Frost, Suffolk, UK

I have been staying in the South of France and watched a large swallowtail butterfly approach a 2m chainlink fence at about the 1m level. The butterfly flew vertically up over the fence and descended immediately on the other side. How did it know to do that? It is possible that it could have gone through the gaps in the fence unscathed but went over the top. Does it "see" the fence as an obstacle (as we do) or is it guided by micro air currents telling it this a "cliff" or other solid object to be avoided? The sun was shining through the fence so it is unlikely to be the lack of light. Any ideas?