A good year for Nightingales, locally

First I hear a pair at Newbourne Springs, then one at Orwell Country Park

Orwell Country Park, not really classic Nightingale habitat of low scrub


and finally one at Mill Stream Nature reserve

Three separate places with a fair amount of human and dog interference in less than a week.

The BTO doesn’t seem to agree that it’s a good year countrywide – Nightingale reporting seems lower than the historical average

Nightingal reporting seems down accordign to Birdtrack

Olympus LS-10 remote control success

I’d experimented with the wired remote for the Olympus LS- series recorders before. I have an Olympus LS-10 and an LS-14, and previous experiments showed I could make this work in principle. There’s a big gap between making it work on the bench and getting it to work in the field, however. This is the next step of boxing it up and making it stand alone.

16F628 PIC is fitted into the space of two batteries in a 4-way battery box, giving me a small box with battery holder and on/off switch. A 32kHz watch crystal gives an easy integer divide down to seconds and then hours, and reduces the power drawn by the PIC and lets me drop down to 2V Vcc and stay in spec over the industrial temperature range.

Either my LS10 is knackered or it never was compatible with Olympus’s wireless remote, it doesn’t provide 3.3V power on the plug tip, so I have to power the PIC 16F628 from two NiMH cells, which means I am short of headroom for 3.3V because there’s a 0.9V difference. I’d expect the PIC to drag the remote control line, which rests at 3.3V down to ~ 3V (2.4V VCC + 0.6V input protection diode drop)

I used a diode for the stop command pulling to ground, which still works with that diode drop, so the drive circuit is

Driving the 3V3 LS10 from a 2.4V PIC

RA4 is an open-drain connection, I figured I would chance the forward-biasing of the input protection diodes via the 100k. It works fine, at least at room temp – a 100ms pull to gnd via RA4 starts the recording, and then a 100ms pull to ground of RA2 stops the recording. Pins are switched to hi-Z inputs when not active. I guess the 3V3 from the LS10 has to go through two diode drops now to get to the 2.4V rail (diode shown and the input protection diode), and this is enough to let it float OK.

I got it to start the recorder at 4am, which is too early, but recording for two hours got me this recording at about 5:30 am of the local birds. I hear Great tit, Robin, Blackbird, some sort of gull, Wren, Woodpigeon, Crow, in that lot.

Using a 3.5mm socket as a workaround for the fiddly 4-pole 2.5mm jack plug – it’s a lot easier to wire a socket than a 4-pole plug, and I got a 4-pole 3.5mm jack to 4-pole 2.5mm jack cable from Ebay. Wiring the 4-way socket is dead easy now, and saves having a flying lead from the box.

In search of microphone weatherproofing ideas

I need to now find a way to get a reasonably weatherproof microphone. Looking at how B&K do this in the manual for the UA1404 the way to go is to use a small raincover just over the mic capsule

B&K’s solution to weatherproofing

Their mention of birds makes me thing this is very close to a mesh nut feeder – I could put horticultural fleece around the mesh and use the top cap as a rain guard. Another option is to go minimalist, recess an omni electret capsule in something like a plastic bottle cap. I’d have thought that the cavity of the raincover would cause dreadful resonances, but if it is say 2cm diameter that would be a wavelength of 330/.02 ~ 16kHz – perhaps theirs is 0.5cm keeping this down to ¼ wavelength. Where this would score is it’s small, and electret mic capsules are cheap so I could afford to lose some. I can take the line that I’ll omit the big foam guard and use a piece of horticultural fleece across the cap, this makes a reasonable wind baffle, and I’m not going to get a good recording if the wind is over 5 mph anyway because of the hiss of the wind in the trees even if I were to keep wind blast out of the mics.

I am thinking of using a small Dribox to rig the recorder and timer, and sample some birdsong from other places. A pair of AAs run the timer for at least three days and the power drain of the LS10 on standby is also low, probably good for a couple of days, but I don’t have more than four hours of recording time on the LS10, it is 2Gb. So I can live with that – the Dribox has enough room for a bigger battery if that starts to look necessary.

Ipswich Sparrow Survey topping out and press event

RSPB Ipswich Local Group leader Chris Courtney and a group of our surveyors met up today at the Brunswick Road Recreation ground for a press event to celebrate the completion of the survey in 2016. (above pic is Chris (L) with Joe Underwood, Ipswich Parks and Wildlife ranger)

Chris Courtney, Ipswich RSPB Local Group leader, and Joe Underwood, Ipswich Parks ranger
Heatmap showing the density of sparrows in Ipswich

Naturally if you’re in the group being photographed you don’t get to take pics of the group 😉 It was good to meet up and put some names ot the faces of our sparrow surveyors from last year and talk with the rangers, who have improved this rec for wildlife.

Alanna, intrepid surveyor of seven Ipswich squares in 2016. Behind is the part of the rec that has been made more wildlife friendly by the rangers and another sparrow colony has been established.

The Sparrows of Ipswich 2016 report.

Sparrows of Ipswich survey 2016 results

The RSPB Ipswich Local Group surveyed the town’s sparrows last year, and we have the results now in. It’s a little bit better than I had thought – strongholds to the north-west and south-east. It’s tough to compare this with the 2006 survey because that wasn’t controlled-effort, although at first glance they still seem to be losing the fight around the Valley Road area relative to the earlier survey.

A short survey of sparrows in Glastonbury

I was in Glastonbury, Somerset, and the house sparrows have started calling at nest sites there, They haven’t started in Ipswich. So I tried the audio recorder/GPS track surveying method. Each of the flags is where there was a male calling, or a male was sighted, along the lines of the BTO survey protcol [ref]Protocol for censusing urban sparrows, DeLaet, Peach and Summers-Smith, British Birds, 104, May 2011, p255 ff[/ref]

I covered a decent area, but not as thoroughly as I thought I had done. The sparrows seem in good heart, however, a more continuous coverage than I feel they are in Ipswich, where the colonies strike me as more fragmented. We will see.

My general impression was that sparrows are doing better in Glastonbury than many parts of Ipswich. The route I took left residential areas for the high Street, I know there are sparrows in Northload street so the two clusters might join.

Bird surveying in the field using GPS

The Ipswich RSPB Local Group is looking at surveying Ipswich’s house sparrows, ten years on after I took part in the first Ipswich Sparrow Survey. Most bird surveys cover a wide, fairly homogeneous area and avian subjects that are mobile over several hundred metres, or specific colonies. Surveying sparrows in the heterogeneous urban environment, with subjects that stay within 70m of the nest site when feeding young are a different kind of challenge.

We didn’t have the benefit of this BTO House Sparrow Survey protocol [ref]Protocol for censusing urban sparrows, DeLaet, Peach and Summers-Smith, British Birds, 104, May 2011, p255 ff[/ref]. As such the results show sample bias from the observer locations, survey effort and the difficulty to getting negative reports. However, it did answer the question ‘where are there sparrows in Ipswich?’, although not the question ‘where are all the sparrows in Ipswich’. It also answered the question ‘where are there no sparrows’ although the sparrowless areas were not exhaustively surveyed. Proving a negative is hard, though the BTO paper shows the way.

In the intervening time I solved the need to create waypoints on a handheld GPS and announce them to tie the audio to the location. Modern audio recorders contain clocks and timestamp the recording, this can be synchronised with the GPX tracks created by the GPS handheld. Smartphone applications like viewranger can also create GPX tracks. However, although a smartphone does many things it doesn’t do any of them very well.

The same trip tracked using Viewranger on a Samsung Android phone versus a Garmin Vista HCx. each machine was in different outside pockets of a coat at the same height above ground. The lighter red tarce is the Garmin which follows the paths better
The same trip tracked using Viewranger on a Samsung Android phone versus a Garmin Vista HCx. each machine was in different outside pockets of a coat at the same height above ground. The lighter red trace is the Garmin which follows the paths better

I set the Samsung to give the most precise location. The issue doesn’t seem to be as simple as the Viewranger Samsung app updating slower than the Garmin, there are enough points, but they aren’t in the right place, particularly when the border trees by the road and railway line

the save trace showing the trees
the save trace showing the trees

The aim of all this was to write a web app to record sparrows in the field. However, it turns out that the Location API is very hit and miss. Sometimes I got 20m accuracy. Sometimes I get 3km accuracy, and I can’t easily see how to fix that, having already selected high geolocation accuracy. If I can’t do that for myself, I certainly can’t support other people using it on two different operating systems and on some mobiles that may not actually have a GPS receiver.


Curlews on the Orwell

Orwell Bridge
Orwell Bridge

I love the sound of curlews, and it was surprising to find these so close to the town, with that wonderful bubbling call. They reach their peak numbers this time of year.

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