With chicks having hatched on successive days over 26th, 27th and 28th April, there seems no chance of the fourth egg now hatching, so we’ll have to hope our brood of three makes it through to fledging successfully. In 2014, the only year to have seen all four eggs hatch here in Sheffield, there was a gap of a couple of days between the third and fourth eggs hatching, after the first three all hatched on the same day (more on that later), but at the end of 2nd May we’re now a good four days since the third egg hatched on 28th April.
In each of the past breeding seasons, the number of chicks known to have hatched has been the number to have fledged, so there’s good reason to be optimistic on that front, especially now we seem to have moved past the cold spell that saw them hatch to temperatures just above freezing. On the brief occasions when the chicks are left unattended, they tend to huddle together, which will help keep them warm. However, it won’t be enough to have any effect on the remaining egg, which is still being brooded by the adults, as evident below.
As is also evident in this screengrab, the egg is finding itself pushed out from prime position under the brood patch by the chicks that have hatched and will grow rapidly. Whatever the reason behind the failure of the fourth egg to hatch, it’s likely that over the next few days it will start to be pushed aside and will eventually be abandoned.
The webcam has allowed insights into some fascinating behaviour over the last few days, something I’ve never seen (or heard of) before. My suspicion that the female is a new mate has re-surfaced as a result of some clumsy incidents, which have seen her scatter the chicks when she’s stood up to leave the nest. One such occasion occurred on Friday 29th when she got up from brooding and left the nest to allow the male to feed the chicks, spilling one of the chicks to the back of the nestbox, its head just visible begging below on the far right-hand side of the inside of the box.
Given their age and stage of development, they cannot walk or move themselves any distance. The male fed the two chicks in the scrape, but noticed the movement at the back of the box and approached the ‘lost’ chick, which is began pecking at. I feared the worst and thought that as it had left the nest it might be seen as a food item. After a few seconds, the male stopped pecking at it and left it alone. Was it still alive?
The female then replaced the male and took over feeding the two chicks before also noticing the displaced chick and also moving over to it, also proceeding to peck at it. My concern suddenly changed to astonishment as she picked it up by the wing and carried it back to the other two chicks and put it down in the centre of the scrape. In the heavily cropped screengrab below, you can make out the chick’s open beak facing upwards as it’s carried.
The female then left the nest with the three chicks back in place, but the third chick missed out on the feed. Subsequently, it seems to have got back into the feeding routines.
Perhaps others know of this behaviour, but it’s not something I’ve ever seen myself nor read about. It may not be as unusual as I thought, for Wendy Bartter, one of the devoted webcam watchers, captured the same behaviour in the middle of the night (!) just prior to the incident I saw. Her terrific video capture can be seen online via the Twitter feed, or here
Back to the question of the eggs hatching at the same time, mentioned at the outset. Another of the fascinating things I’ve learned from Tim Birkhead’s book on eggs is that the eggs in a nest ‘talk’ to each other shortly before hatching, making a series of sounds that are audible to other chicks in eggs in the brood, though it seems this depends on the eggs touching each other, so the cues may also be sensory. This is what enables many species to synchronise the emergence of their broods, and is another reason to feel that the fourth egg had not developed and will not hatch.
I made a couple of visits to St George’s on Saturday and saw the male perched on the church for most of the time, out of sight of the webcam but in earshot of the female as she brooded the chicks and keeping an eye out for potential threats (a passing Crow was of particular interest). A picture from below as he circled back to his watchpoint.