Garden Wildlife (3) - The Wren and the Brood of Great Tits

In my previous post I wrote about a wren that had taken up delivering food to a nest box occupied by great tits. This dynamic continued for the duration of the nest’s active period.

It became increasingly apparent that we were down to a single great tit parent. The male was nowhere to be seen. The female great tit was still regularly bringing food to the box, and the wren once or twice sang revealing it to be a he. Therefore the box was being tended to by a female great tit and a male wren!

To recap, the chicks of the great tits hatched on 28^th April and on 6^th May the wren starting bringing food in and taking away the faecal sacs. For a full 9 days the wren tended to the nest, and throughout this period the wren wrestled with a continuing issue; he wanted to bring food in, but sometimes the female great tit was already in the nest! At 9.1 grams for a wren versus 16 grams for a great tit, he was significantly outsized. Plus the tit’s sharp claws and relatively strong beak must have made entering the occupied nest a daunting prospect.

It seems that he needn’t have been worried as throughout the rearing process I saw zero animosity or aggression from the great tit towards the wren. Perhaps she realised he was helping her out? Whatever the case was, our unlikely duo were judiciously attentive to the growing inhabitants of the nest. But what exactly was in the nest?

Unfortunately there was no convenient inspection hatch on this box. The only way to look in would have been through the hole, through which I couldn’t see anything, or unscrew the side panel, but that seemed far too invasive and risky. As the days went on the chicks got louder and louder, leading me to question whether you can identify the species of chick by their sounds. I felt that it should be possible and that it’s something to work on! It didn’t sound as though there were two types of chick in there, but the realisation came that finding out exactly what is in there would have to wait until the nest ran its course.

On 9^th May I noticed a second wren in the garden. The behaviour of this individual was quite unlike that of our star character. For starters this one was not attending the nest of a great tit, and was acting more like a typical wren just skulking around the undergrowth. It seemed likely that this second bird had a territory/ nest somewhere beyond the far corner of our garden as it repeatedly and consistently flew off in that direction. What was interesting to see was when our box-feeding wren saw this second wren he would depress his tail and tremble his wings while making a clacking rattle sound. I’m not too sure what the relationship between these two was/ is, but the second individual showed no interest in the nest box.

On 14^th May the chicks were raucous, it seemed as though the box couldn’t contain them any longer. According to the literature we were now well in fledging time, so it was anytime soon. Both species were still bringing in food. And then on the morning of 15^th May all was silent. I couldn’t believe that I’d missed the fledging! I assumed they had gone at some obnoxious time in the small hours. The wren came to the box, poked his head in, and left it be. Despite much searching I found no evidence of the chicks or for that matter the female great tit.

I waited until the following day to open up the box, as it was obviously spent by this time. Opening up the side it was clear to see there was only the one nest inside, so the wren had indeed been feeding a different species! But on looking at the contents of the nest unfortunately it contained 4 deceased great tit chicks. Whether some chicks fledged and these ones remained I couldn’t say for sure, but I feel that this possibility is the less likely outcome. The odds seem to indicate that the nest failed overnight. The temperature had been low. It is now towards the end of May and I haven’t seen a female great tit around the garden since 14^th May, the day of the loud chicks.

I’m not going to lie, I found this a most unsatisfying ending! Unfortunately the great tits failed, but life carries on and the wren was seen later in the day with nesting material, and he soon started singing once more.

- Hugh Baggaley