A truly excellent site about these birds
But possibly the best information of a practical nature
for our purposes is to be found on the British
RSPB's website (Royal Society for the Protection of Birds)
at their page
Information.
Breeding: Tend to pair up during January and may start nest hunting in mid-February. But breeding is geared to appearance of natural foods such as caterpillars and insects so they do not begin nesting in earnest until cold snaps are over.
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If one parent dies during the incubation period, the other will abandon the nest; it cannot cope alone. Once the eggs have hatched, a sole parent will usually manage to rear some of the young.
It is an exceptionally warm winter....
At 10am on Sunday 12th December 1999 a bird was seen entering the box. The "BirdTV" setup was hastily put together again and the new occupant was seen inspecting the camera, flying up and giving it several resounding whacks. After several comings and goings the new bird seemed content (he is larger than the previous occupants) to settle down. We are delighted to have a new occupant. Christopher says that these birds frequently move in some months ahead of the nesting season, to establish "squatter's rights" and defend their choice territory against other interested parties.
After dark the new bird settled down for the night. It seemed that a good name would be Fluff. Here then is Fluff, fluffed.
13th December 1999. About dusk (local sunset is at 15.50 GMT) the bird comes back again and proceeds to explore the nestbox as on the 12th. Many heavy bangs with his beak on the camera box make loud noises; when the light level fell so that Fluff could no longer see his reflection in the perspex camera cover, he settled down and went to sleep. Here is a reminder of the appearance of the camera, viewed inside the box from below.
It takes over an hour for Fluff to settle and finally he puts his head under his wing and goes to sleep. He spends time preening, and listening to the noises of the night outside, as in this picture, where there is a rattling and tapping noise on the box, possibly caused by an antenna wire blowing against it in the wind. The outside temperature is about 6 C.
14th December 1999. About 2 hours before local sunrise (which occurs at 07.58 GMT local time) Fluff starts to shiver and shake and look around to see if it is time to get up. It is cold outside, 5C, and there is a light wind blowing. The bird has been asleep since about 16.50 GMT on the 13th, or a total of 13 hours, so must have lost a lot of heat energy in that time. We see why he is fluffed. No light being visible, he goes back to sleep.
The bird body temperature is about 41C so there is a temperature difference of about 36C between his core and the outside world. He weighs, we are told, about 10 grams including the heat insulating feathers. It must be quite a feat to stay warm. Being in a sheltered nest box at least reduces the wind chill factor for him. Some years ago, before global warming cut in, the winter temperatures here used to fall as low as -20C at night. In those conditions, survival must be difficult.
If we could imagine Fluff without any feathers, a large part of his bulk would be occupied by his head. As we see above, there are not many feathers insulating his head, which is why he has to poke it into his back-feathers at night when sleeping. It is the same for humans; on a cold day much heat is lost through the head, which is why it was commonplace for people to wear hats before everyone went around in motor cars.
At 07.25, the bird shook himself, and departed into the faint morning light for breakfast. It was about 30 minutes before sunrise and the ground frost had left a layer of ice on the pond. Fluff had been roosting for over 15 hours.
10.45 GMT 14 Dec 99, Fluff in profile.
15th December 1999. This morning there was a dusting of snow up the A3. We have unearthed the max-min indoor-outdoor digital thermometers, re-equipped them with new batteries (after 8 years) and hung a sensor by the nestbox. It records 0.2 Celsius at 22.30 GMT; Fluff is a little restless this evening, adjusting his position frequently.
A student project is being undertaken to make a temperature "bird in box" detector for data-logging purposes. When Fluff is foraging tomorrow we shall drill a little hole beneath his roosting spot and position the outdoor sensor where it can measure any temperature rise underneath him. We hope this will not deter him from using the box.
We are also in the throes of acquiring a second VCR, a long play version that will record 8 hours onto a tape. We also intend to use this to produce a 1 hour video of last year's "edited highlights of the nesting season" from the 100 hours of video recording we have stored. This will then free up 36 video tapes to re-use.
Parus caerulaeus are said to need 1 kilocalorie per gram of body mass per day in food intake to stay alive. For a 10-12 gram bird this puts the heat production at an average of about 500 milliwatts. Measurements on the nestbox power supply show that it it delivering 12.5 volts at 120 mA or 1.5 watts, a fair proportion of which is in the form of infrared radiation from the camera heater and the illuminator LEDs. Thus Fluff has some slight energy advantage over being in an unpowered nestbox. If the weather shows signs of really hard frosts we may consider additional sources of heat for the bird. "Centrally heated nestbox, des. res. in Guildford." (A common roosting site is said to be in street lights.)
The air temperature by the box at 00.01 on 16/12/99 is -0.8 Celsius.
Here is a flash photo of the nestbox with its thermometers in place.
The bird does not mind the small thermometer sensor in the middle of the bottom of the box. With the bird absent, the two sensors (the one you see in the bottom of the box and the other in free air tied to the grey wire) read the same plus or minus 0.3 Celsius. With the bird in the box the reading is consistently 0.7 to 0.8 Celsius higher on the under-bird sensor. Careful inspection of the TV image seems to suggest the bird is standing on his feet rather than sitting down with his tummy on the thermometer.
The air temperature at 17.00 GMT on 16th December 1999 is 5 degrees C. Fluff came in to roost ten minutes after local sunset (which was at 15.52 GMT today).
Here is the bird, carefully avoiding sitting on the sensor which is ringed in black. The in-the-box thermometer reads 4.4 Celsius and the air thermometer reads 3.9 Celsius.
And a few minutes later the bird has moved squarely over the sensor head. The in-the-box thermometer reads 4.6 Celsius and the air thermometer reads 3.8 Celsius.
20th December 1999. An eventful few days, coinciding with an outage of the web computers for maintenance. On Saturday night it snowed. On Sunday morning (19th December) the snow was lying, providing an incentive to CJ (age 8) to rush out and make a commotion, ice-braking. But not before the bird had spent an agitated morning in the box, looking out at the snow repeatedly. As we have hardly had any snow in Guildford over the last few years, it is likely that this bird is too young to have learned about snow. Our bird, on hearing the tremendous smash of the ice breaking, departed and was not seen again for five hours, until it came in briefly at 4.10pm. It looked most unsettled, and departed shortly afterwards to roost elsewhere for the night. The minimum temperature on Sunday night was -7 Celsius in the nestbox.
The following morning (Monday) there were several visits by a bird with a wicked long triangular beak, who couldn't get through the box hole. We think this may have been one of the Greater Spotted Woodpeckers, resident in our garden, who are commonly seen on the nut feeders. Woodpeckers are known to be predators of nesting Parus. As our bird was not at home, the visitor rapidly lost interest and went away.
On Monday 20th bird was seen briefly in the morning and at mid-day, then not until 30 minutes after sunset, when it came back and took far longer than normal to settle. It seemed shaggy and rough by comparison with its earlier sleek appearance, and kept settling and reawakening, rocking around and scrabbling with its feet, and shaking in an uncontrolled and agitated manner. Perhaps it is feeling the cold.
Here is a picture of it looking uncomfortable.
And here is another picture showing its disturbed upper feathers, after it had settled.
We hope it will learn to cope with the inclement weather, which is forecast to persist for several more days. The temperature outside the box is -1.5 C and the temperature under the bird, in the box, is -0.8 C at 17.10 GMT. Last night the thermometers were convergent on the same temperature, between -7.0 and -2.0, while the bird was absent.
18.15 GMT 20-12-99. We think our bird has caught a cold, "bird flu" possibly? Anyway, he can't stay asleep for more than five minutes at a stretch without waking up and doing a cross between a cough, a sneeze, and a tweet. When he does this, it is very sudden, and his beak lurches forwards and hits the wood with a resounding bang.
21.40 GMT 21-12-99. The bird is coughing and sneezing and chirping much more frequently this evening. While I have been marking microwave exam scripts for two hours, he has been sneezing on average every one or two minutes and, judging by the rasping noise, the infection may have gone to his chest. We see the disadvantage of a single day's setback to the bird on the edge of the selection pressures. The snow and ice have gone, and the outside temperature is 4.8 Celsius. We feel that a slug of Lemsip(tm) would do him the world of good, but as with last year's birds, this kind of bird watching is strictly a spectator sport and "not for the birds"; no interventions are possible or desirable.
Our bird has taken to coughing with its head tucked in. This causes it to stagger around in the box. Thus there is now no doubt at all that it is standing up to sleep, and therefore not sitting on the floor of the box and the thermometer sensor. Occasionally it has to stretch out a wing and fan out its tail to regain its balance.
We feel it is a mistake to refer to this bird by name, as we may get attached to him and it is not clear that he is going to last very long.
As advertised, the nearly-full-moon is very bright and illuminating the outdoor scene. Occasional fireworks are being let off; our bird is impervious to the loud bangs. It seems it is only very local noises (tapping on the box) which provoke any reaction at all.
19:40 GMT 22-12-99. Our bird is much better today, and can easily roost for 30 minutes without sneezing. It has been raining today and the bird has been sheltering for much of the time, to avoid getting wet. It is now 10.2 Celsius outside, and the bird looks much sleeker in the picture below.
12.20GMT 29-12-99. There has been little new action to report until this morning. Many birds have been flocking to the nut feeders outside, as the weather was cold overnight. Our bird has been in and out of the box frequently, chasing away the competition, and hammering with its beak on the inside of the wood box to make a tapping sound which seems to be a territorial claim signal. It has been patrolling the garden patch and has no hesitation in having a go at any of its species which it sees as a threat to its nestbox-occupancy.
Our bird is remarkably sanguine; we are letting off a single firework every evening between Christmas and the New Year on the patio, about 3 metres from the nestbox hole. The bird wakes up, shakes its head, but is not very upset by this commotion.
16:20 GMT 31-12-99, the last posting of the 19**s. Our bird came in five minutes after local sunset, for the last time this millennium. Where do the birds go for the last half hour before sunset? It is completely quiet on the nut feeders, there are few if any birds flying across the sky, they have not yet gone to roost...
Our bird was most energetic this afternoon, coming and going frequently and hammering away inside the box to chase away the competition. As energetic as we have seen him so far... and he seems to be successfully defending his territory. After coming and going every five minutes throughout the day he disappeared to the East at 15.30 and didn't reappear until 16.05, when he flew in from the West.
There have been several of his species in the garden this afternoon, and many others, including at least a dozen goldfinches and the greater spotted woodpecker. Our bird is relatively unconcerned about other species, but reacts strongly to the presence of others of its own species. The Mother of all firework displays is scheduled for midnight; we shall not be around to see his reaction.
09:00 on the First of January 2000. A battle for posession of the nestbox is raging. Two birds are perching on the box and a third looking on from the nut feeders. Full use is being made of the resonance from the plastic camera cover, this is very noisy on the camera microphone. Unfortunately, as the birds are all similar in size and to our eyes have no distinguishing features, we can't identify the various protagonists as individuals.
One bird, when inside, spreads its wings to make itself look as large and threatening as possible to the bird looking in from outside.
There seems to be a scattering of new droppings in the box. Perhaps this has something to do with territorial marking. In any case, the bird has been sporadically cleaning up and removing the individual pellets from the nestbox.
d.jefferies@surrey.ac.uk David Jefferies 4th March 2000