View From The Shed by Volunteer Shaun - I WISH I'D BROUGHT MY BROLLY

I WISH I’D BROUGHT MY BROLLY

One of the joys of retirement is that I can take small holidays whenever I want. I've just been away on another small break (more on that next week), so I’m writing this piece a few days in advance of publication. I can’t be 100% sure, but if the weather has been anything like predicted then the chances are that the past week would have featured some heavy precipitation. We shouldn’t really be surprised by this, it is Autumn after all. Heavy rain is to be expected at this time of year. It might be a slight inconvenience for us if we get caught in a serious storm without our waterproofs but for our smaller birds the consequences could be much worse than that. It could be the difference between life and the soggy alternative.

Waterfowl are well adapted for soggy weather of course. They spend a big chunk of their lives swimming and feeding in the stuff so a bit more water falling on them from above doesn’t make too much difference. Songbirds though are at real risk if the weather is wet and miserable for days on end. 

Their prime enemy is the cold. If the water and wind gets through to their skin then they could easily get hypothermia and frankly, that would quickly be the end of a small bird like a Sparrow or a Robin. They might find it difficult to fly too if the rain is prolonged. Heavy, waterlogged feathers make flight almost impossible for a tiny songbird. They wouldn’t even attempt to fly if that were the case. But the main reason birds don’t fly in rain is not the water in the air, it’s the low pressure associated with rainstorms. I’m no scientist (as I’m about to prove with my exceedingly sketchy grasp of this subject) but as I understand it, the low pressure equates to a lower density in the air and a lower number of molecules for a bird to push their little wings against. They need the aerodynamic lift that lots of molecules provide and if it isn’t there then they have to flap much harder to keep themselves airborne…  or something like that.  In a nutshell, it takes a lot more effort to fly when the air pressure is low. Songbirds are pretty much always living on a knife edge so anything that makes their lives more difficult is to be avoided wherever possible. So they’ll try to avoid flying and wait the storm out. Hunkering down somewhere relatively dry and sheltered is the order of the day.

Birds can sense a change in the weather up to two days beforehand. Scientists aren’t all agreed on how they do it but one quite likely theory is that they can sense a change in pressure from an approaching air front via the air sacs within their body. See my ‘Every Breath You Take’ blog about how birds breathe for more details on those. If it’s just a light shower a small bird will simply fluff up its feathers and try to keep dry. Most birds have a preen gland that produces a waterproofing oil that they spread over their feathers. The amount and effectiveness of this oil varies massively from species to species but the majority of birds can make themselves reasonably waterproof. The bird is more concerned about being cold than a bit damp so it will create space between the feathers to trap air and associated heat within. It’s the same theory as you or me wearing lots of layers of clothing rather than one big thick jumper. The heat is contained in the trapped air, just like the warmth under a duvet. 

Different feathers and even different parts of the same feather perform various functions in helping the bird cope with bad weather. The outer “contour” feathers zip together to create a waterproof but breathable fine mesh that keeps the water out but the warm air in. The downy feathers beneath stay dry and keep the bird warm - again, it’s just like me beneath my duvet. All this talk of it is making me crave my bed. But I’ll press on…

A serious downpour is a different matter though. In this case the bird will seek shelter, perhaps under a bush or within a shrub . Even in these hard to reach places though, water will find a way and the bird will make small physical amendments to keep itself as dry as possible. lt will flatten its feathers tight to ensure that water runs off them more easily. A ‘heads up’ posture helps too. They’ll withdraw their heads, stand straight upright and point their beak towards the worst of the weather. These little changes, evolved over thousands of years, make them just that little bit more streamlined so that the water runs off their feathers just that little bit more easily. These tiny bits add up and may just be enough to save their little birdy lives.

But even if they’re totally protected against the rain reaching their skin, a songbird cannot stay under cover for too long. Unlike us, most small birds cannot last a day without food. The rainfall may last for many days so they have to venture out to feed, several times a day at the very least. There’s no Deliveroo in the bird world so they make short journeys to grab a quick feed and then head back to shelter.

Once the rain stops - and it always does, eventually - the birds will go into a frenzy of preening and shaking the water from their feathers. Each one needs to be tended to, cleaned and zipped back into place alongside their neighbouring feathers. And then there’s the small matter of feeding to make up for the hunger while waiting out the storm. It’s a frantic time, but they can tell how long they have until the next weather front arrives.

So next time the first drops of rain hit your window pane, spare a thought for the birds in your garden. You probably won’t see them. They’ll have been hiding away for a while beforehand. And who can blame them?