11 April -- Back to the woods
HOPING to get down to Kent today. A big gap. Too many things seem to be crowding out the plans to follow these birds more closely. It happens every year! Why is spring so busy? Time has passed so quickly. It's now only a week until the nestbox owl pair's eggs hatch.
Anyway, tonight or tomorrow the firm intention is to get the tent pitched for a night's listening and recording near the nestbox. At least the weather's improving (again!); temperature's been as low as 2°C some nights in the woods, but we now have forecasts of daytime temps going well over 10°C. Less than 5°C and being immobile outside at night is a recipe for hypothermia!
12 April -- The tent is pitched for the first night out
8.45pm: Just back indoors after pitching the tent. Putting it up was a hassle -- the instructions and told one to put the wrong poles in the wrong slots. And it certainly wasn't a job one person could do on their own . . I had to telephone Corinne, who'd gone off to feed lettuce to the Guinea Fowl, to come and assist. All that noise of fabric, accompanied by grunts and curses, must have alarmed the normally cool Mrs O as, when I checked the nestbox with binos half way through, she wasn't there. She'd flown without me seeing. She'll be back, I tell myself hopefully
So, at last we're there. Tonight, after a good supper, I'll be out in the tent with recording gear. Just the Telinga this time so I can arrive at least half quietly. The Telinga with its dish (see photos below) should be the ideal setup to hear and record everything that's going on in the nestbox.
It's been a beautiful day -- 10°C warmer than any previous day, with bright sun. It's an abrupt change. Two nights ago there was a snowfall in Kent that made the front page of The Daily Telegraph, with a photo of a lamb looking bemused by two inches of fast melting snow.
Tonight should be good. The males were already hooting as we returned through the woods to the house. It's dry and the moon is full. Last night when I arrived from London it had only just cleared up after a day of continuous rain, and, listening from the house, all I heard from the pine tree pair between 11 and midnight was a desultory-sounding exchange. I got the impression the male had been lurking in the wood behind all the time (no long approach with hoots like in the recording of 4 April) and that the greeting was a low-key exchange between two rather damp owls. During the same pre-midnight stretch I heard another female. Where she was it was impossible to tell. (Postscript: it turned out that there were two more Tawny Owls pairs within earshot of the house.)
Photos of the Nestbox Camp and equipment (12 April)
Evening, 12th April. With some difficulty the tent is set up about 25 yards from the nestbox, which can be seen at top right on its beech trunk. I'm waiting for the oak scrub to come into leaf to provide some cover from the footpath, but in the meantime have thrown some camouflage over the tent to make it a little less conspicuous.
Pic on left shows tent looking southeast (as in top pic) towards the pine stand in which these two tawnies have used crows' nests in previous years. Pic on right looks northeast through the oak wood through which the owls fly from their main hunting area in the fields that start about 100 yards off to the left.
For anyone who might be wondering I should explain that to do this sort of recording one sits all night with headphones on monitoring what's being picked up. In a way this detracts from the experience of hearing the owls with one's unaided ears, and it's also impossible to tell exactly what direction an owl is in when it's not more or less in front of the dish. This is something you can easily do with headphones off. On the other hand a mic like the Telinga's has so much gain (amplification) that I can hear, say, Mr Owl hooting quite a bit further away than I would normally be able to -- even behind the dish. In turn, the downside of this huge gain is that all other noises become amplified, making it difficult to get nice recordings except on the quietest nights. The lightest rain or wind becomes very obtrusive, and until you get used to it even a mouse foraging delicately in dry leaves some distance away can leave you feeling quite creepy! In the daytime another thing one hears very clearly is the hum of all the insects feeding in the oak canopy.
First night under nestbox 12-13 April
When I turned up at 10.45 pm the female was not there. After two anxious hours of waiting and worrying on my part, she at last came in and settled on her eggs. What a relief! That was 12.50 am. At about 3 am the male visited and she appears to have gone off with him, only to return after another long absence. After dawn I cussed that I'd left my binos in the house as without them I couldn't see her in the box. It was only during a mid-morning visit with binos that I was able to be completely sure that she was back and stationed in the box for the day.
Well, this is all interesting first-time information about her habits! As the night went on I'd felt growing alarm that the tent-pitching activities had proved too disturbing and she might be abandoning her brood. Her long absences were making me consider this a real possibility. Hour after hour I was picturing the clutch of eggs up there getting colder and colder during what became a chilly night -- I'd guess less than 5°C at dawn.
So when I finally saw her in the box at 11 am the next morning I felt huge relief. Only then could I accept the second possible explanation of her behaviour -- that after a longish period of cold, rainy weather she was simply very hungry and spent much of the night hunting with her mate. Our noisy activities the evening before may certainly have given her the pretext to fly off, but having left maybe she decided to make a night of it and find something to eat for herself.
What's interesting, then, is that when brooding eggs the female tawny may go off to find her own food. In this case at least the male did visit, but I heard no evidence that he brought a meal. (I can't see what's going on, but with the dish it's like having a microphone almost next to her.) It's interesting that she's prepared to leave the eggs for such long periods -- perhaps up to five or six hours, and certainly for a couple of hours, during which they must go stone cold.
(Postscript: Some females do leave first-laid eggs to go cold in the early stages, in a practice I've called "delayed incubation". But this clutch is not far off the hatch date. Delayed incubation was very evident with a pair of owls using a camera-equipped nestbox in Peterborough in 2007 and is fairly thoroughly documented in the Cambridgeshire Owls on this website.)
The night was so light that even I felt I had owl vision! Although quite low as it passed across the southern sky, the moon lit the woods so brightly that it was like the time before dawn.
powered by owls
Left: the dish microphone setup. The tent has a neat "porch" which protects the mic from rain, as I quickly discovered the first night! Right: the mic and dish on a camera tripod. It would be impossible to hand hold this gear all night, but supporting it like this does restrict one's ability to train the dish on calls coming from anywhere but the nestbox. Never mind .. listening with the dish isalmost like having a microphone inside the nestbox.