the Cambridgeshire Tawny Owls January-March 2007
THIS PAGE STARTS WITH THE GOOD NEWS that all of the eggs have hatched. Those who've read from the beginning will know that this Tawny Owl pair hasn't had much success over the past two years, with a mix of bad luck (squirrel invasion) and infertility. So it was a big relief to hear from the nestbox owner that a first chick was born on 21 February. I didn't see the female out that night as she left the nestbox just after 1 am on 22nd when I was flat on my back with a stonking headache after shopping, and I was only able to get the last set of pics on the previous page after she'd returned. The second and third chicks hatched some time on 22 Feb. So all hatched within about 24 hours. (So my suggestion on the previous page that egg no. 2 hatched first has to be thrown out as it was based on the notion that no. 1 was infertile.)
This owl pair is unusual in that the female has laid extremely early for the UK. As the National Geographic News report on the previous page makes clear, these occurrences aren't altogether unknown, with five cases of tawnies laying between December 2002 and January 2003 reported to the BTO. That of course means there must be many more early layers who go unseen and unreported.
On with the story . . .
22 February (cont.)
10.45 pm: She's still in the box. Pic of the chick coming as soon as there's one to have. Meanwhile, here's the delightful sound that'll be heard from the box now:
00.25 am: Unbelieveable. It looks as though there may be three chicks. Difficult to tell as with their silvery-white fluff their images burn out and they tend to group together. (The camera also has a rather quickly acting cut-out and the feed went.) Never mind -- this is really good news.
Photo montage: After looking up at the door for some minutes, the mother left for a well-earned break at about 20 past midnight and was back 5 minutes later. I managed to get the next three shots before being timed out. There are definitely two chicks, one at the top and one at the bottom of the white mass in each pic. They can be clearly distinguished by their separate movements. What's not possible to tell is whether there's a third chick in the centre or just an egg. If there is a third chick it will be remarkable as two nights ago (00.25 am on 21 Feb), when I got a shot of all three eggs, the first egg laid would have been 31 days old, and nearly a day older when the first chick was heard cheeping just before 6 pm later the same day.
Felicitations to the mother! Here's a mother with her chick, recorded from our own nestbox soon after the previous clip:
The happy mother, early morning
23 February 2007
Another email from the nestbox owner: "The other 2 eggs hatched yesterday 22/02/07. Visual confirmation 00.19 today. 3 owlets to be fed -- that should keep the adults busy!"
So there are three chicks! Talk about delayed brooding. This mum has managed to hatch three eggs laid at least five days apart within as little as 24 hours (between first cheeps at about 6 pm on 21st and all three being seen soon after midnight last night). That gives an average time to hatching of about 30 days (32, 30 and 28). Looks as if Southern was on to something (see previous page). On top of that it's often supposed that tawnies space their chicks for good reason. But here we have a mother who's carefully managed all the hatchings into one 24-hour period. Curiouser and curiouser. Did I say somewhere that one can learn a lot from a nestbox cam? I feel I'm learning a lot from this!
Countdown to fledging
The period from hatching to fledging is a bit more reliable (mum can't do much about it!) though having quite a range of 30-35 days. But in several studies the average period has been much the same: 32 days. That's 25 March for the eldest hatchling, with chicks jumping up to the door and even venturing outside from up to a week beforehand. That'll be about the time most sensible tawnies are starting their eggs!
Before that happens, it'll be interesting to see when she starts to leave the chicks on their own and spends more time outside. With luck, after something like 10-12 days the mother won't be sitting with them all the time and we should be able to see much more of them. Just now they're very small, with a thin layer of fluff, and need to be kept warm.
Magic box: The nestbox at 4.55 pm today. Who'd have guessed at the little drama being played out inside? Right: a nice, if grainy, pic of the mother just after 7.30 pm.
8.48-9.01 pm: Mother's treated herself to all of a 13-minute break. You see her looking up in a certain way and somehow you know what she's thinking, because she often looks up without coming out. The chicks were huddled closely together with little movement, so no advance on what was visible last night.
What I've not been able to catch is a visit by the dad. Food drops by males tend to be very brief affairs at 40-min to 1-hour intervals, so that's not altogether surprising.
My turn for a break . . .
I need to do some work!! Fascinating as it's been, following the adventures of ths owl family takes time. The next ten days or so are likely to be quiet and, touch wood, without surprises. So apart from putting up the occasional note or pic I'm going to leave them to get on with it.
4.45 pm: My first opportunity for some time to peep into the box. All looks well, mother's there and there was a hint of a chick's head by her side. During the day there's too much light to get good pics, so I'll check again after dark, now about 6.15 pm. The chicks will now be 10-11 days old, so there's a good chance the mother will soon be spending more time out, if she isn't already. The weather forecasts for the next 10 days are bad, with frequent rain expected. Here in London it's been raining most of the day; the nestbox (outside view) looks wet and the tree is rocking a little. Yesterday was a beautiful day in Kent, with warm spring sunshine. As the chicks won't be fledging until about 25th March we'll be out of the currently forecast bad patch, but who knows what's to come.
10 pm: Mother's just left, after making the tell-tale signs of wanting to leave for some time. Three delightful little white chicks are visible, huddled together at the bottom of the box but now with some facial detail discernible. Eyes don't seem to be open yet, though it's difficult to tell. My impression from our own is that at first they open them just a tiny crack, only really opening them up towards their 15th day. Simple explanation may be that they're snoozing! They're not moving around -- just facing each other in a little pyramid of white chick fluff. In the pic on the right they were looking up soon after the mother left.
Lots more debris on the floor now. Most of it probably the remains of meals, but increasingly there'll be additions in the form of wet chick poo and pellets. I don't think it's known whether Tawny Owl young excrete fecal sacs, which the mother would remove from the nest, like their American cousins the Barred Owl. But one thing's for sure -- with the chicks growing fast and eating all their father can catch it's going to get damp and very, very smelly down there!
The chicks are now 10 and 11 days old ...
Can Tawny Owls smell? I believe so. The female I'm currently giving a home becomes very agitated if she's left in a confined space with one of her smellier poos. The moment the mess, and the stench, are removed she calms down. So there's grounds for believing that the growing pong in an owl cavity nest is at least a contributory reason to why the female leaves for good once the chicks have reached a certain age.
00.15-00.59 am (5 March): When I logged on at quarter past midnight the mother was out, and she did not return until I was writing this entry, so she's definitely into longer breaks. The chicks remained in much the same position as in the pic above for the entire time she was out. It makes one wonder whether the two with their beaks close together are forming a bond (they stayed with heads and beaks close all the time), with the third at the back who's looking up at the camera left out. This is an interesting feature that's seen in the OwlCam video, where the two older chicks clearly fomed such a bond and were still keeping each other's company months after leaving the nestbox. The youngest chick was excluded from this pairing and had to do everything on his own.
11.53 am: Quite a nice day again, and this is how the pics from the cameras appear during the day. They used to be on separate pages, but they're now side by side on the same page, which is a great help for viewing. Temperatures down here in London, 70 miles south of the nestbox location, have been quite mild, so if that continues it'll be favourable for the owl family and the prospects of finding enough to feed five tawnies.
7.45 pm: The (camera!) feed hasn't been working for some hours so there may be no more pics today. It's got colder and a wind's picked up.
5.15 pm: Cameras are up and running again and all looks well. Mother is with chicks, now 12 and 13 days old. (To see how chicks develop from this age up to day 100, try my First 100 Days pages.)
7.05 pm: She's out, chicks are fine. Nothing new to show since last photo of chicks. They're huddled together in much the same way except that all three are now facing each other. Sweet!
7.37 pm: She's come back. So another long break out -- at least 35 min (I didn't get the start time). What's she up to? Our mother owl would go to a nearby tree and wait for her mate to come in with food. He would give it to her to bring to the chicks. The frame rate wasn't fast enough to see if this female had anything in her beak, and as she's sitting over the chicks in the box it's difficult to tell if she's feeding them. Does she go hunting for food herself? Possibly, but a tawny mother's instinct seems to be to stay in the vicinity of her chicks all the time. That was certainly the impression I had from our nestbox mother last year. The furthest away she'd go was about 100 yards in the direction of where the male was hunting to call to him. But almost always when she was out she'd be at a watching perch about 40 yards away.
7.47 pm: Here she is 10 minutes after returning, with a chick's head just under her beak (clock's running a little ahead of itself)
8.23 pm: Whoops! Just caught her about to leave again. The pic above shows her craning her head round the box. As she peered intently in this direction for some time it may indicate where her husband is hunting. She left shortly after, allowing another view of the three chicks (below).
9.25 pm: She's still away. That's one full hour.
The chicks remained in their little huddle for all the time I saw them after the mother left, with no sign of the pairing I was speculating about last night.
I now have to sign off as I need to get ready for a return to Kent. Many chores to do, but one thing that will definitely not be a chore is finalising the camera setup in our own nestbox. Our mother owl had not started laying last time I was down a few days ago, nor had another female who nested near the house last year. I'll be able to watch the Cambridgeshire family but won't unfortunately be able to post news until I'm back in London next week. By then the chicks will be about 20 days old and things should get interesting!
A note on the website says that the chicks were ringed today. There are some delightful pics that show, at last, what they really look like, in colour and by daylight!
Chicks are fine. Now 21 and 22 days old. they occupy most of the floor space. I've checked from time to time over the past nine days and found the mother in only rarely. A few updating pics coming tomorrow. We've had some beautiful weather recently and the chicks are looking well fed. Our own owls haven't started to lay yet! We've heard one pair and the nestbox female appears to have paid a visit to her box.
01.12-01.28 am: The mum's just spent 16 minutes with them. Looks like she brought in a bird. For about three minutes beforehand the chicks were all peering up in eager anticipation. It's likely she was sitting nearby when the dad came with his catch and handed it over to her -- the chicks would have been alerted by their calls of greeting and some frolicking around before she came in -- at least that's what happens with ours.
Here's a clip to illustrate. This is our nestbox owls. The dish was focused on the chicks, but listen to what's going on in the background! Nestbox visit (1.14 Mb). The dad arrives (taking me by surprise) and the mother is overjoyed to meet up with him. At this stage our chicks were 26 and 22 days old. That's the Tenterden church clock striking midnight at the end. The chicks were fed about five minutes later.
The montage shows the feed from the time the chicks became alert to when the mother left the box (she took off in the direction of the house, which the box faces). The whole episode lasted about 20 minutes. It's difficult to tell what she brought in -- it may be a decapitated rat (see enlargement in the montage). There's a ten-minute gap between two of the lower pics during which she appeared to be feeding them bits of the prey, but the video grabs show little more than can be seen here. Ideally one needs a camera that's lower down and more to the side of the chicks to see that sort of detail.
Does a father Tawny Owl have anything to do with his chicks? In the case of our nestbox owls, yes. In 2004, when they were raising two chicks in a crow's nest, we found the father on the nest at least twice, in the early afternoon. There's no possibility of mistaking him for the lighter-coloured female as he's a very foxy-coloured bird and each has a quite distinct "face". This was when the chicks were still quite young. I don't know whether he did his turn when they were using the nestbox in 2006 as I was up nights with them and slept during the day. At night his task was to find food and he spent no time in the nestbox. I have never seen the Cambridgeshire female's partner.
About ten days to fledging on the chicks' day 32. Another fine day here in London. The long-range weather forecast I mentioned on 4 March turns out to have been complete rubbish.
7 pm: Here are the chicks this evening, one 23 days old (as of about 6 pm) and the other two 22. The IR camera doesn't show it, but they'll now be getting quite brown in colour -- as indeed they already were on 13th March when they were ringed aged 19 and 20 days.
The forecasters are talking of an "Arctic" spell ahead. I think what they mean is that temperatures may get within shouting distance of zero. The worst I can see for the owls' area on the BBC's weather site is zero on Sunday night (18th) and minus 2°C on Monday night, with a bit of a wind accentuating the chill on Sunday. These little owls should be quite ok as there are three, they have a good feather and down cover and the box has thick walls. In fact they might find it quite a relief to have some fresh air blown down to them.
Lower photo: a 20-day old chick from my First Hundred Days series. This is a chick from the parents who are heard in the recording above, though she was born the year before.
8.30 pm: Wind's been getting up here in London. Where the owlets are it's 12°C with a 23 mph SW wind, and you can see their walnut tree is rocking slightly. Tomorrow the pressure's going to fall quickly, and by tomorrow night the temperature will be just above zero with a 30 mph wind. That's apparently to be followed by a string of nights with near- or just sub-zero temperatures, though with somewhat milder daytime temperatures.
So spring is temporarily gone and the owlets will feel their first real chill.
Right: Three expectant little faces just before 9 pm. Possibly the mother was just calling because she didn't come to the box over the next few minutes.
01.00 am (18th March): It's farewell to the wee bairns for the night. No sign of the mother when I've checked in during the evening. Owls don't seem to care much for wind and maybe the dad's having difficulty hunting tonight. The cradle is continuing to rock and the chicks have been in a huddle every time I've looked in.
12.30 pm: Right: pics taken with the IR camera during the day seem to be better and show the increasingly dark colouration of the owl chicks, as well as more detail. This evening they'll be 25 and 24 days old.
The BBC weather forecasts are turning out to be correct. Last night was quite gusty, with long quieter intervals. Wind is in the west, turning north later and taking night temperatures down to zero. The wind up where the owls are is said to be 29 mph, and it certainly looks it from the outside camera. Temp is a reasonable 7°C at the moment.
My own little owl is both fascinated and frightened by the wind. She's sitting on a bird perch next to the kitchen window watching and listening to all its effects. Two years ago I was with an owl display on a wet, gusty midsummer's day. The owls looked absolutely miserable because the wind blew all their soft feathers up the wrong way.
Middle pic: a 25-day-old chick. At this stage they develop this curious peaked look to their heads. I'd expect to see the Cambridgeshire owlets exercising their wings soon (haven't seen it yet), and an appearance at the entrance maybe some time midweek.
3 pm: Well! No sooner written than seen. An owlet is flying right up the box and then hanging on to one of the rungs with its beak (bottom pic). The other two watch with interest from the floor. The box is rocking like the crow's nest on a ship's mast. I'd advise him or her to stay well inside today.
3.10 pm: The cameras have gone down! What a time for this to happen.
3.35 pm: Up and running again. Oh my. I really began to fear the worst. Chick no. 1 very active.
5.35 pm: Owlets in a safe huddle at the bottom of the box.
7 pm: Cameras unobtainable because a stats counter doesn't load. This happens from time to time and can make chick checks an unpredictable activity! They're unlikely to jump around at night though.
7.35 pm: Wind appears to have dropped, but so has the temperature: 2°C at 6 pm, going down to 1°C. Chicks are in a huddle as usual. Being three rather than two must be quite an advantage in cold weather. Wonder if they'll get fed tonight.
00.30 am (19 Mar): Last check, all well.
More on delayed incubation by owls (see entries and this box on page 1 for the context of this discussion)
A seasoned owl observer from the US writes that he heard from an owl breeder in England who saw delayed incubation in her Tawny Owls. The female would appear to be incubating the first egg, but when the egg was checked it was cold to the touch. Real incubation did not start until the second egg was laid.
He noted the same thing with his own Barred Owls, which were using a camera-equipped nestbox. Here too the female did not start real incubation until the second egg was laid. Intrigued that his owls weren't behaving as the reference books said they should, incubating as soon as the first egg was laid, he asked a Barred Owl expert about the discrepancy. The expert suggested that the field researchers had probably got it wrong, as what he was able to see with his side-view camera would have looked like incubation to a distant observer.
So it does look as though delayed incubation may be quite common practice among certain owls.
powered by owls
The female laid a clutch of three eggs between 20 and 27 January. The first egg to hatch did so on 21 February. This page continues the story from the day after this happy event.