Friday 29 April 2016

BirdBox2016: eggs at last

This season has certainly been unusual compared to the 7 previous years.

Following an unusually mild winter we have had to suffer a lot of cold, and often gloomy days during April.

So while we have generally noticed eggs appearing in our nest boxes in early April, this year we have had to wait a few weeks longer.

It only occurred to me recently that it would have been a good idea (over the years) to have recorded the progress made by trees in my garden during April, as a means for determining the onset of spring.

Well, let's start now.

Tree log - 29th April 2016

I have photographed the buds/leaves of three species of tree and one shrub. I still maintain they are way behind, but may have to eat my words in April 2017 if the pictures turn out the same.

the horse chesnut

The horse chesnut (conkers to you) is the first tree to develop leaves in our garden. Small garden birds seem to hide in it (I don't know if its a food source), collard doves like to meet & mate in there, and great spotted woodpeckers like to hammer at the trunk.

Canadian Maple

This is our Canadian Maple, and the home of the blue tit bird box. It has large leaves (or it will have) and so provides great cover. I think blackbirds, jays and black caps hide there, so they can drop down on our cherry tree and steal the fruit.

the hazel is the home of the green caterpillar

The Hazel is the tree I most closely associate with blue tits. With chicks in the nest, the adults can be seen flying between nest and hazel to collect large quantities of green caterpillar.

The Vitis

The Vitis is a vine related to the grape, but with small bitter fruit. This covers our pergola (the home of the empty tit box). It provides a completely shaded patio for us in the summer, and is a good source of spiders and insects for the birds.


Although I mentioned in an earlier post (9th April) that I thought our female blue tit had stayed over-night in the nest, I'm no longer 100% certain that she did. As my bird box system is only "on" when it has recently been triggered via the detector at the box entrance, I have to be very careful when interpreting the log files.

To be sure, I have now set the low level light to turn on automatically when the system starts. This means that if the box is on early in the morning or late in the evening, I can see enough detail in the dark video to know if a bird is in or out of the box. So if I see the female in the box some time after 7pm and the box is not triggered again until the morning, I know she has been in all night.

I noticed something a few days ago that I haven't witnessed a blue tit or great tit do so far. On the 26th our female entered the box just after 7pm. She settled down quickly and I was convinced she was set to stay the night. But around 7.30pm she up and left!

The following morning at about 5.50am she came back to the nest, laid her first egg, and then left again. Judging by the logs, she left by about 6am, as the box automatically shut down around 6.20am.

This 'fly in, lay egg, then leave' sequence is one we have seen before with robins. I'll have to pay more attention to tits behaviour in the future.

Honest! There are 3 eggs there, somewhere.

Once the first egg was laid, both male and female have almost stopped coming to the nest during the day (maybe the system gets turned on two or three times, but nothing like the frequency of the pre-egg stage). The female also flies straight into the nest in the evening, and does not loiter at the entrance. She has also stayed in the nest over-night since the first egg was laid.

How will things pan out?

Once again I will plot progress on a chart, with an initial plan showing very approximate expected timings.

You can compare this with the charts for 2014 (great tits) and 2015 (blue tits).

I still haven't given up all hope with the second bird box. We have a lot of great tits coming into the garden to feed, and some of the males still appear to be calling for mates.

As for the robins, I can't find their nest. They are not using any of the sites used in recent years. We don't see the female very often so I think she is probably sitting on a clutch of eggs.

Our emperor moths are still "sleeping" in the garage, but we have heard from friends who's moths have already emerged.

N.B. BirdBox2017

While it is a pity that the UV lights in the other nest have not been given a fair trial ( determine if we can sex blue tits) I think next year I'll include iRed lights (in addition to white) so we can run them through the night.

I will also need to auto-adjust the video 'motion' threshold somehow, so that video is captured for lower light level variations at night.

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