My system has collected a lot of data.
Can it tell me anything?
And what do I do now?
the current system
My mcguire89 based BirdNet-Pi system has been quietly sitting in the loft, gathering data via a small microphone hanging out the roof at the back of the house. While its range is naturally limited, it certainly identifies some of the birds in my back garden, some of the noisy birds on my roof, and a few of the louder birds flying overhead.
The minimum % confidence level was set to 75% for most, but not all, of the year. I don't know what %confidence represents but should imaging that (in this case) a given detection matches 75% of the reference points for a given species.
Resample resolution was set to 15 minutes; which I think means several detections of the same species within 15 minutes are registered as one count.
I also lost a few recording (they were purged by the system) due to lack of storage capacity, but no data was lost from the database.
This system has two rather annoying issues;
1) The Species Stats seem to be compiled up until the last time/date the system was re-booted. Not a huge problem as I simply reboot if I want to look at up-to-date graphical information.
2) The spectrogram image of the successful captured detection contains a trace at around 8-9kHz.
However, this spurious 'signal' is not there when Live Monitoring spectrogram is enabled, so seems to be part of the analysis process.
Patrick McGuire stopped work on this system software during 2023.
plans for 2025 system
I plan to build a new 'software' image based upon the Nachtzuster fork of BirdNet-Pi during December, ready for January. I'm hoping the 2 issues above will magically 'be gone'.
Once set up, I plan not to fiddle with any settings during 2025, thereby maintaining a consistent month-by-month comparison.
Data for (mostly) 2024
The system lists 101 species of birds detected in the last 12 month (December to December).
I suspect some of these (where only 1 or 2 detections occurred for a given species) are species errors, but the 2 recordings of cuckoo in June appear genuine. And as we are just a mile or two from the Pagham RSPB Reserve, the vast majority are certainly possible (e.g. Canada Goose, Northern Lapwing, Whooper Swan, kingfisher & so on).
However the single, mid-day recording of a tawny owl does seem a little suspect. It scrapes in with a %confidence of 75.97%, although the recordings certainly include an 'owl like' sound (...and owls have been heard on our estate at night).
The Top 20 by detection count;
Nothing too surprising here except for the redwing and the number of detections for the chiffchaff.
From 100 to 1000 detections;
From 20 to 100 detections;
The mention of 'Dog' is because some of these detections may be due to a neighbour's dog barking.
Less than 20;
...there are more & more water birds on the list!
5 or less;
I'm still trying to make sense of this data, but thought some of it worth posting.
Just to state the obvious; if a bird doesn't make a sound, it can't be recorded by this system. I say this because (as an example) we have wood pigeons in the garden virtually every day of the year, but they are almost 'mute' during the winter, although extremely vocal for the rest of the time.
During the summer, a pair of blackbirds nested somewhere in our garden, and the chart shows a correspondingly high level of vocalisation.
But these were not sweet calls, they were 99% alarm calls as the pair followed a neighbour's cat, as it prowled along the fence line.
At some point in the future, systems like this will classify calls based upon type; e.g. Song #1, #2, #3, Alarm call #1, #2 & so on. (...or maybe even; Alarm call cat, alarm call sparrowhawk!).
The redwing is an example of a bird generally known for its night flight calls (NFC) and from this circular 'time' chart almost all occur during [winter] night time.
The blue tit & great tit calls both follow a fairly predictable pattern, increasing in number during the mating/nesting season.
For the rest of the year they make good use of our bird feeders.
The peak of calls is probably down to just a single male, while the winter calls may be due to a number of individuals, maybe from a mixed species winter flock.
I don't think the coal tits bred in either our, or our near neighbours gardens.
Likewise the long-tailed tits and green finch were mostly visiting the feeders.
The hawfinch interests me. Although we've never seen one in our garden, they have been seen in nearby gardens.
Likewise the bullfinch, which does not hang on our feeders, but does poke around under hedges & shrubs.
The black redstart is a bird we saw a lot on our recent trip to Gibraltar & southern Spain. I'm now convinced I spotted these in our garden during the summer.
Unlike the Pied wagtail and the grey wagtail, the white wagtail is described as a 'passage migrant' passing through Britain from early March to May, and then going south from mid-August to early November.
I don't seemed to have any detection data early in the year, so maybe they flock and feed up here on the south coast just in the autumn before crossing back into europe.
The chiffchaff data shows a big increase in detection during the autumn.
Most migrate south, however a small but increasing percentage are resident.
A reference on the net said "Most of them arrive in March and have departed by September." In my data, the 'garden peak' for detections is around the last week in September. Quite a few must have hung around into October.
As a ground or low-level nesting bird, the chiffchaff will never breed successfully in our garden due to predation by cats and possibly squirrels.
See also:-
https://github.com/mcguirepr89/BirdNET-Pi
https://github.com/Nachtzuster/BirdNET-Pi
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