Friday 6 May 2016

BirdBox2016: incubating 9 eggs

The local weather has certainly improved over the last few days, with today exceeding 27'C (if my pressure/temperature monitor can be relied upon).

Our blue tit pair seem to have produced 9 eggs, and the female has started sitting on them.

And our first female Emperor moth emerged yesterday and attracted a mate this afternoon.
It really feels like we have turned a corner, with hotter days and warmer nights.

Don't know why the temps look a bit lumpy around the mid 20s

Maple Tree birdbox

Although we are quite happy that our blue tits have produced 9 eggs, the blue tit video monitor at our local nature park (Buchan Country Park) shows they have 12 eggs.

9 eggs, not too shabby!

It is thought that the birds clutch size is in some way governed by the size/quality of the available food source (e.g. territory & suitable trees). But how does that work?

I don't know, but we seem to get clutches between 8-10 eggs in our garden boxes. Maybe we need to plant more hazel trees!

Now that it looks like the final egg has been laid, its time to update my chart.

I got lucky with my guess that she would lay 9 eggs. But it is never clear to me whether the female starts the incubation process a day before the last egg is laid. It certainly looks like it, but just because she appears to be sitting on the eggs, it doesn't mean the process has started.

I think it generally takes 14 days for the chicks to hatch, so I would still expect the first chicks to appear around 17th May.

Pergola birdbox

We had a bit of excitement about a week ago when a second pair of blue tits turned up. After maybe 5 minutes of viewing the Pergola box from the inside, the female wasted no time in stripping lengths of bark from the vitis and loading them into the box.

Unfortunately this only lasted 20 minutes before the Maple Tree male came back and caught them in the act. This little guy is so pumped up and aggressive, that he chased them away.

They did come back a couple of times during the afternoon, but each time they were driven away, and the female was unable to make any further progress. I think a similar situation occurred a few weeks earlier in the very old, non-monitored box by our compost heap. I could see a pair going in and out just for a few hours one afternoon.

Oh well! The Pergola box (which is the PicaxePi version with the UV lights) is unlikely to see any real action for another year.

The Emperor moths

Our moths are just starting to emerge after 12 months of going through the caterpillar/cocoon phases and over-wintering in the garage. I think they are about 3 weeks later than 2014 and about 10 days later than 2015.

a slightly under-sized female Emperor moth

Caterpillars given to some of our local friends have emerged a few days earlier, but they have generally been stored is cool rooms rather than a freezing garage.

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