Sunday, 31 March 2013

Barn owls!

Well down here in good old Suffolk, winter's grip is still strong and a fantastic photo, taken by my good friend Em Johnson of the wonderful Iken Barns (a really nice place to stay if you ever think of visiting Suffolk), brought home to me how it's not only us that suffer during this very prolonged bleak spell. 
A powerful image caught in Iken, Suffolk.  © Em Johnson.
Barn owls are crepuscular birds, they prefer or are more active around dawn and dusk. They're not daytime hunting birds and seeing one hunting in the daylight is a sign that all is not well. Owls, like most birds of prey, fly for only one reason, to hunt and they only hunt when they're hungry or have chicks to feed. They do not fly or hunt for pleasure, flying in the daylight leaves them vulnerable to attack from larger birds such as seagulls, rooks, etc (known as mobbing). Also, trying to hunt in these conditions will be extremely hard for the bird whose primary hunting technique is based primarily on sound. The face of the owl on photo above shows the heart shape of the face of a barn owl. The heart shape is not for looks, it serves a purpose, which is to direct any sound that the owl is facing directly to the ears. Notice how the perimeter of the face is 'pinched' around the level of the eye. This is where the ears are and this pinch is the deepest set part of the face, all sound is directed to this point. Here's another interesting fact, the ears are asymmetrical. This means that unlike us, the are not level, one ear is higher than the other and again there is a purpose behind it. The ears being off kilter help the owl to triangulate exactly where a sound is coming from, so that even in total darkness, it can pin point its prey. The eyes are also unusual in that, unlike us, they cannot move in the eye socket, they are always pointing straight ahead. This means that when the owl hears a sound, its head turns to pinpoint exactly where the sound originated from, which means its eyes are looking directly at it. If they can see their prey as well as it hear it, the chance of capture is much higher than just by sound alone.
Their hearing is very sensitive, so much so, that trying to hunt in the rain is a bit like listening to the constant hiss on an untuned radio. It would be very hard to hear the rustle of a field/bank vole or mouse amongst all that noise. The same goes with snow, sounds become incredibly muffled and the chances of a successful hunt are low compared to precipitation free times.
So the picture above paints a very bleak picture for our owls, in fact 2 days after this pic was captured, I too saw an owl hunting in broad daylight at 3pm in the afternoon, not good. This obvious lack of food caused by the prolonged winter we're having, could also have an effect on the breeding cycle of the owls. Owls will only lay as many eggs that they feel they can cater for, i.e. if food is plentiful, they could lay up to and around 8 eggs, yet if food is scarce then only a couple of eggs might be laid.
This picture also highlights other issues, such as the lack of food. The weather has also affected the vole and mice, the crops, grasses and insects they feed on, are still deep in the ground and therefore they are not breeding too. Again, it's all about 'interrelationships' (I love that word) and how everything is interlinked and dependant on other organisms for its survival. When an imbalance occurs, such as the prolonged bad weather, this has a knock on effect with the plants and insects, which affects those reliant on the plants and insects and so forth and so on. So, it's important at times like this that our feeders are kept topped up and water trays are kept defrosted. It doesn't help all of nature, but it gives it just a helping hand.
Although saying that, it's funny how we don't have feeders for birds of prey. But then I don't think several live mice hanging from your bird feeder would go down well with most garden lovers, nor the RSPCA for that matter (I'm just kidding, please DO NOT try this at home). 

Just for the record

Moth trap was set last night. Last year I caught 53 moths of 9 different species and the minimum temp was 6ºC.
Last night I caught nothing, but then the minimum temp was a very unseasonal -3.2ºC (yes, MINUS).

Not good.

Have a good easter peeps.

Till next time.

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