Tuesday, 4 June 2019

warbling in the night

work in progress

I was cruising up to Semington last month, and as I approached Marsh Farm near Hilperton I heard a sudden burst of birdsong. "A Cetti's warbler?" I wondered, and slipped the engine into neutral and coasted, listening intently. There was no repeat performance though.

Next morning I cycled down to Bradford on Avon to pick up the car, and paused for a while at Marsh Farm, but no Cetti's did I hear. Discussing it on the canal Facebook page, though, a friend moored at Whaddon, half a mile or so on from Marsh Farm, sent me a recording he'd made, and lo! It was a Cetti's warbler. The song is very distinctive; hugely emphatic, with an initial introductory note and a pause, like the HWAET that precedes an Old English poem, then a sudden quickfire burst of notes, repeated a few times.

Now I'm back down below Bradford, at one of my favourite spots; Horse Field, looking up from my desk at the hillside where at this moment two crows are swaggering about like Wild West gunslingers who've just done ridden into town, and the rabbits are keeping a wary eye on them; a few months ago I saw a crow attack and kill a rabbit over there, though the long grass spared me the gory details. Two mornings ago I glanced up to see a roebuck trotting down the hill towards me. 

It stepped into the copse at the bottom of the field and presumably stayed there all day. Unless you see where deer have holed up, you'll almost certainly be entirely unaware of their presence; three roe deer spent the day in the woods opposite the boat a while ago, and it was only because I saw them arrive that I could recognise the white tails and the occasional flicker of movement.

Last time I was here I'd heard a mysterious bird in the middle of the night (or at least it felt like that), and wondered for a while, then forgot about it. But I heard it again a few nights ago, and made a recording of it. It's quite far away, so you'll have to listen carefully. It's a Cetti's warbler. Two things stopped me identifying it the first time round; one was that the song is much shorter than the usual song, and the bigger one was that I had got used to the idea that there are no Cetti's warblers around here. Over the last few summers I'd only ever heard them east of the Bruce Tunnel, between Pewsey and Hungerford. Anyway, have a quick listen.

I do try not to make assumptions, but often fail, and the assumptions can get in the way of learning something new. Hence my failure to recognise this bird the first time I heard it. I did get annoyed when someone else did it to me a while ago on Twitter; when they mentioned the rarity of water voles I remarked on the number of times I've seen them on the canal, and she replied "lots of people think they've seen water voles when they're actually rats." Uh huh.

The brevity of its song here seems to be characteristic of it singing in the dark; it begins between 0230 and 0300, long before any other bird around here (though sedge warblers can and will sing all night). There's a handy site called xeno-canto, where you can hear all sorts of bird sounds, and a night-singing Cetti's in a recording there sounds just like the one I heard. In the daytime, by the way, it goes back to the full song, but it's so far away (down by the river) and so short and episodic, that it tends to get drowned out by the noise and bustle of the daytime canal.

On the mystery bird front, here's something that Liz Williamson heard at Stourhead. Had me flummoxed, but I wondered if it was a jay, because jays often mimic other birds; I've heard them do a convincing buzzard, heron, and even (in Bristol, near the zoo) howler monkeys. Behold, xeno-canto turned up a recording of a jay sounding just like this. What is it mimicking, though? -sounds like a Scops owl?

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