23 April

HAVE A GOOD LOOK at the pine nest in the morning. As has been mentioned before, I'm worried about the chicks falling out of this crow's nest later on. I go directly under the nest and line up the branches between it and the ground. There are two whoppers about 15 feet below that'll knock the chicks to kingdom come if they do fall. I think about sawing them off.

But further inspection of the nest itself allays my fears. The reason is that unlike the pines where the nestbox owls used to nest these have better developed crowns. They're just denser, and they spread more sideways, with a thicker tangle of twigs. The nest is in fact some way out from the trunk, on a node, where it's surrounded by a mat of twigs. I realise that if (it's a matter of when really) these chicks back off to the side to poo they will have a chance of scrambling back on to the nest. This is quite different from the plantation trees, where the crown is poorly developed and the crows' nests are balanced on a branch right next to the trunk (see pic on page 2). There there is no mat of twigs, and a chick backing to the edge simply takes a walk into the void. It's like walking the gangplank backwards.


25 April -- microphone stuff (skip to pics below if this is not your cup of tea)

FOR ANY ONE who might be interested (mic buffs), here's the same three excerpts that appear in the "Owl or train" sample on the previous page but recorded with the Rode NT1-A microphones. These are heavy studio cardioid mics with a 1 inch diaphragm, but believe it or not some nature recordists drag them outside because (1) they make nice recordings and (2) they have fabulously low self-noise -- ie no hiss that you're ever going to hear. These were the mics I had on ordinary studio stands about 20 feet back from the nest, and of course facing it, though 10-12 feet apart and angled slightly away from each other. The recording on the previous page was, like all recordings in this diary so far, made with the Telinga in its dish. I've applied a bass roll-off filter to the Rode recording to make it sound more similar to the Telinga as the latter has an on-board filter whereas the Rodes don't. Without the filter the mics tend to pick up a deep bass roar if there's any wind or distant traffic, and this can sound very odd.

Owl or train on Rode NT1A 1.2 Mb

The first excerpt in the track -- with the train -- doesn't sound too different. The second excerpt, of the chicks, shows how useful the dish is -- the chick noises hardly show up in this recording. The third excerpt, of the male owl arriving and leaving, is where the differences between the two micing setups really show up.

Below are some clips to show this. They're from the third excerpt in the track, ie the owl encounter. They're all A-B comparisons -- that is, one short extract from one microphone followed immediately by a recording of the same event from the other. In all cases the Telinga goes first, followed by the Rode NT1-As.

Just as would be expected, the Telinga and dish produce a more focused, precise sound with much less of the ambience (surrounding noise) picked up by the Rodes. By contrast, the Rodes seem to produce a somewhat fuller sound -- listen especially to her calls. I don't know whether this is an illusion caused by ambient echo or whether it reflects the one disadvantage of the Telinga, which is its oversensitivity to high frequencies, a characteristic that's emphasized when it's used with the dish. Probably both.

Sample AB1 160 kb. He arrives. Two kewicks plus hoot. 4 sec each, total 8 s. (In all three samples Telinga is first, then Rode NT1-As).

Sample AB2 256 kb. His departing calls with kewicks from her. 6.4 sec each, total 12.8 s.

Sample AB3 44 kb. Single departing hoot. 1 sec each, total 2 s.

So, the interesting question is what would happen if one mixed both recordings to get the best of both worlds -- to combine the "close-up" focus of the dish microphone with the ambience and fuller sound produced by the cardioids (the Rodes). Trouble is, there are 100 ways you could do this, with different combinations of the volume of each and of by how much you offset one recording from the other. Anyway, here is one example of a combination in which the Rode recording has been given a touch more prominence and there is no offset -- the recordings have been mixed starting from as close to the same instant in time as can be identified on the tracks. This shouldn't produce serious interference problems as in detail the mics are recording very different sounds.

Mixed tracks 600 kb. Complete encounter with Telinga and Rode recordings mixed, with slight suppression of Telinga. 30 seconds.

It does work, but I'm not sure how well it works! And probably won't be until I've listened to A-B comparisons and done some different mixes with different offsets. It should be remembered that the dish was focused on her and not on him when he flew off leaving a trail of echoes -- I don't know whether he flew off in the line of the dish or in some other direction.

The potential of this technique is obvious: use cardioids or omnis to collect ambience and focus on indvidual birds with the dish to bring them in close.


27 April -- Where the owls live

LONDON. Enough of head and ear stuff. Here's some light relief by way of some background on where the owls live

During a visit to the woods in early September 2005 we found the nestbox stuffed full of beech twigs and leaves. Early nest preparation activity by an enthusiastic female tawny? No, a grey squirrel -- tawnies don't make nests and, lazy creatures that they are, they go for ready-made sites. So we hauled the ladder out and emptied the box. The pic on the left shows another small visitor to the nestbox that day. Sophie, last year's daughter of the owl pair who are using the box, loves going for walks in the woods -- day or night. She wears jesses and sits on my shoulder, good as gold.

The Scots Pines where the Nestbox pair used to nest and the nestbox tree

An aerial view of the triangular stand of Scots Pines in which this owl pair used to nest. It's the bluish area at middle right, next to the ride. In the big version the pines are marked with a box, and near the top of this box, about half way along the short side of the pines, can be seen the yellowish crown of the beech to which the nestbox is attached. Almost all of the area on the left of the pic is a magnificent wood of large oaks, while the stand between the two rides is (I think) young larch. The ride in the top right corner is not actually a ride but carries an electrical distribution line. These pose a serious hazard to any medium or large bird, and I instinctively check the bases of any poles I pass! In the UK there is no requirement to make these lines safe, unlike in many states in the US.

The rest of the territory -- the fields where the Nestbox owls hunt

This is where the voles and rats are caught -- the parent owls' hunting grounds in fields off to the top of the photo above and looking back towards the wood, which begins behind the house at top left. The territory extends beyond the area shown here: I've heard the dad in the strip of fields beyond the top right corner, and a farmer has seen them on his buildings off to the left. Maybe that's where the rats are caught. When not nesting they seem to roost in the trees in the hedgerows between these fields, although I have seen the female in the woods in summer.

Off to the right of this pic is Hemsted Forest, where territories occupied by other tawnies start.

Continues on next page (p.12)

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