Captain Bodgit: BirdNet-Pi: Species Stats

Wednesday, 8 May 2024

BirdNet-Pi: Species Stats

We are well into the 2024 BirdBox season.

Last year, blue tits made use of our new woodcrete bird box...

...but this year the great tits are having a turn.

We haven't really been paying much attention to the comings & goings around the birdbox. It was looking like a pair of curious great tits may have gone off and found somewhere more suitable.

Great tit checking out our woodcrete birdbox

But then, at the beginning of May, the activity level suddenly increased, and it was clear they had eggs which were now hatching!

Species stats

One of the features on the BirdNet-Pi system is species stats. As this system has been running since December 2023, I took a look at the details for great tit calls.

The first thing to strike me about this bird call chart was that call activity didn't really pick up until April. I was expecting to see lots of calls early, when the male would have been trying to attract a mate.

The great tit call peak is around 7th April

By the end of March/start of April I presume this couple would have already found one another. But maybe they became a pair [somewhere else] and then came into our garden and found the nestbox.

And by April, when the call activity had picked up, the male was certainly making his very familiar tea-cher, tea-cher, tea-cher call.

The multi-frequency burst is the tea sound, cher is the 4kHz horizontal line

Mostly this is a sequence of 3 sounds, but sometimes he makes a sequence of 4 sounds. And quite often he makes a truncated call: tea-cher, tea-cher , tea

Notice that the 3rd cher (4kHz) is missing

Who knows what this slight difference in these calls means? I suspect that it doesn't make any difference to the call meaning, because great tits seem to have a wide repertoire of calls anyway.

Getting back to the charts, why did our male great tit call more frequently around early April this year?

Using data from previous years, when we had the benefit of birdbox cameras, we can work backwards from the day the first chicks started to hatch, which I think was 2nd May.

Incubation would have commenced about 13-14 days earlier, which is around 18th April. This would have been about the time the last egg was laid.

If we assume the female has laid 9 eggs, this takes us back to, say, 9-10th April.

Therefore the male is calling most frequently about the time that the birds are mating. So the call could be territorial, he could be saying "stay away from here, stay away from my woman!" ...who knows.

Does this mean that the famous tea-cher, tea-cher, tea-cher call is only used to warn males off and not to attract females? ...I still don't know!

Blue tit species stats

The chart of call detections for blue tits is quite similar to the great tits...

the peak is around 17th - 22nd April

...except the peak is later.

I don't know where the blue tits are nesting, but they 'hunt' in our garden and therefore may only be a few gardens away from us.

The only way we might get a better idea regarding their progress is if their family turns up one day at our feeder. We may be able to work the dates back to calculate whether the peak calls also coincides with their mating.

Coal tit species stats

We see and hear coal tits in and around our garden. Their chart looks like this...

...but I've no idea what's going on. I doubt that they nest close by, and there may be several nesting pairs, but I can't deduce anything from this data.

From past experience I would have said they generally nest earlier than blue or great tits (they sometimes nested at our previous location).

the Robin stats

The robin is highly territorial for most of the year, so you can hear one almost everyday, almost anywhere!

...maybe this will make more sense when i have a full 12 months of data.

the Dunnock stats

And finally we have the dunnock, which I know very little about...

seems to peak late February/early March

...but will be keeping an eye on its chart as the year progresses.

Captain Bodgit

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