BIRD B0X FILES 2003: MAY PAGE

updated 18th May

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Thurs 1st May...Incubation continues, the female sitting for all but a few breaks in each hour of daylight. The male is feeding her regularly with grubs, a few blossom buds and what appears to be powdered peanuts from the feeder. Here she is seen with her head deep in the nest, turning and moving the eggs. This probably ensures even warming of the clutch, something that is done manually in an artificial incubator for chicks on a farm.
Friday 2nd May....Midnight ; note the darker image, even with infra-red illumination. The female is fast asleep and hasn't moved for 20 minutes. Her breathing is only just visible on a movie. As the weather is so cold and wet, I have made a makeshift mealworm feeder from plastic bottles to increase the amount of live food available to the male in the territory. Incubation continues and should take around 14 days if everything goes well.

Wednesday 7th May...The female is struggling to eat a particularly large and tough mealworm here. She had to stand up and gulp for several seconds before it went down fighting! The male is finding plenty of food for her, mostly grubs and caterpillars from a nearby apple tree. He made in excess of 100 visits to the nestbox today. Incubation continues safely so far and hatching may be expected from perhaps Sunday 11th May if all goes well, probably later.

Friday 9th May...The nest is being compressed under the weight and activity of the incubating female. The cup is now very clearly defined and deep. She has started to import more soft and feathery material. She even appeared with three loads of very bright red scarlet fleece this morning which makes me wish we had a colour camera. The male continues with feeding her an almost 100% diet of grubs and caterpillars with no flying insects or spiders noted. It's getting very close to the time of hatching.
SUNDAY 11th May...right on time, hatching commenced early this morning. Four, or possibly five nestlings are visible and active. The female is removing a large piece of eggshell from the box here. She eats small pieces of the shell herself, recovering important minerals lost during egg formation and laying.

SUNDAY 11th May...the female feeding a broken piece of grub to a nestling. The male is still doing all the food gathering and the female a mixture of incubating and brooding to keep the tiny (18mm long) naked nestlings warm. He presents a grub to the female and they gently tug it into bits to feed the minute open mouths or 'gapes.'

SUNDAY 11th May...In the absence of both parents, a nestling is gaping with an obvious diamond shaped mouth inviting feeding from a visiting parent. The mouth or 'gape' is circled in green and perhaps 7mm across.
SUNDAY 11th May...Don't eat your lunch before reading this! For several days after hatching the female consumes any waste from the nestlings. Here she is removing and eating a 'packet of poo' coloured very obviously white from the nestling presenting its rear end. By doing this, the adults ensure minimal infestation from flies and parasites and ensure the nest site is as clean and healthy as it can be.

MONDAY 12th May...The image shows the hatched nestlings tucked up together in the nest cup. Click on the picture to download a 2 Mb timelapse film showing the female brooding and the nestlings movement. There appears to be at least one egg still to hatch though counting up the birds is just about impossible. When they become more active in about a week you will be able to count open beaks begging to be fed.

MONDAY 12th May.... I've tried to enlarge an image and highlight some features. The male is feeding one nestling on the left. The white diamond shape circled in orange is the open beak or gape which induces the male to gently place food inside. Below, the two dark bulges are the eyes which are currently closed. On the right I have outlined another nestling in blue to indicate the size in comparison with an adult head. The nestlings are completely naked and feather development will slowly start to take place having hatched.
MONDAY 12th May, 10pm.... A change to behaviour in the pair. For the first time the male is now roosting in the box with the female. Whether this is a strategy to increase the warmth within the nest area or part of the importance of pair-bonding I don't know. It's a bit unscientific to say it, but it's rather sweet now that the eggs have hatched.
WEDNESDAY 14th May, 10am...The nestlings are already larger and being fed regularly. In spite of the stormy cold weather, at least eight appear to have survived so far and appear equally active. I can see no evidence of the ninth and know that the egg had not hatched by Monday night. It may be at the bottom of the nest or have been removed by the parents. I have copied the nest cup and circled each mouth in red in the top right hand corner. Eight mouths are visible.
FRIDAY 16th May...The nestlings are now capable of a more varied diet. The adults found a supply of flies this afternoon and they were able to feed the brood at least 50 in under an hour. Here both parents have returned at the same time with a fly each which is swallowed whole.
FRIDAY 16th May...The female is finding brooding the nestlings less easy. They are very active and fill the nest. She has to lean to one side and cover them with a wing very often, though they still push through. The nestlings are very likely to be affected by cold and starving in difficult weather and often many die. So far, in spite of the wind and rain, the family is doing well.
SUNDAY 18th May 8am.....A quick beak count shows at least eight survivors now one week old. Seven heads on the left of the nest and one under a piece of grass on the right. They are all seriously demanding and bad weather is not stopping a regular food supply being brought to the nest. The nestlings heads are about the size of their entire body at hatching so they are growing fast. The dark lines on their backs and heads is the start of feather development.

TUESDAY 3rd June...The cold and wet weather, possibly combined with disease within the nestbox caused a catastrophic loss of the nestlings. After eight days, the numbers of survivors dwindled daily in ones and twos. By Wednesday 21st May a single nestling, strong, healthy and well fed by the parents remained. The weather stayed cold and wet. In spite of careful roosting by the parents and plentiful feeding, this last chick died a day later. The photograph shows the last carcass in decay some 10 days later. The suspected 9th egg that did not hatch is also now revealed. It is a sad fact, though true, that the mortality rate of such small birds is very high. The slightest drop in temperature, increase in rain, or loss of food can have enormous problems for the birds. This is why they lay so many eggs in the hope that one or two at least survive. In this case, unfortunately, none did. The parents are still defending their territory though are very unlikely to attempt to breed again, and within two or three days, neither returned to the box. Perhaps next year they will try again. Local news from friends shows that similar failures have occurred in many Blue Tit boxes.

On a brighter note, there are at least three successful Great Tit boxes on the Christ Church site, the one over the boiler house chimney producing at least 7 young. There are also three Magpie nests, a Mistle Thrush, four Carrion Crow, seven known Robin, and 16 House Sparrow nests all either successful or near to fledging. Most interestingly, a group of Bullfinches was seen today, 3 juveniles just fledged, a male and a female. This has not been recorded locally to Christ Church before.