Background

The nest box was positioned on the side of the wooden garage in 1989 and most years has been used by blue-tits for nesting during April and May. Since 1997 the box has been fitted with a miniature infra-red black & white camera.

Blue-tits time their breeding to coincide with the caterpillars emerging to eat the new leaves on the surrounding trees. Even though they eat nuts and seeds in the winter, they prefer to feed their fast-growing young on high protein insects, caterpillars, and aphids. Because they only breed once in the year, they lay a large number of eggs, in 1997 they laid 14 eggs, 8 hatched, and 6 fledged.

In 1998 the weather was so bad that our nest was abandoned at the nestbuilding stage; this happened to many others around here that summer. In 1999, we first published the pictures on the Web. After late nestbuilding, eggs successfully hatched, but the nest was destroyed by a cat the day after the young hatched. In 2000 extra precautions were taken to make the box safe from cats but no birds chose to use the box.

In 2001 they laid 10 eggs, but after hatching on 10 May, they all died within two days presumably because the parents couldn’t find food for them – this was generally found to have been a bad year for bluetits. The box wasn’t used in 2002 or 2003.

In 2004, the first egg was laid on 14 April and the female started sleeping in the box overnight. She laid one egg each morning and would leave the eggs uncovered for about an hour before returning to cover them with nest material. She started incubating them after laying the 9th egg on 22 April, she stayed in the box on the eggs for most of the day and all night and frequently turned the eggs around so the pattern of eggs was constantly changing. Delaying incubation ensures that they all hatch at the same time after about 12-14 days. During incubation she can leave them uncovered for up to an hour at a time. They started hatching on 5 May: five in the afternoon, two during the night, one at breakfast time on 6 May, and the last one the day after that on 7 May. When they’re so tiny, it’s very difficult to count the open mouths because they writhe around so much; one must have been weaker than the rest and on 10 May, we realised that there were only 8 gapes being opened, so one must have died. The chicks stayed confined to the nest bowl area of the nest box until they were 10 days old on 15 May and then started lurking immediately under the hole waiting for food. Both parents have been constantly feeding them insects and caterpillars every few minutes from dawn (5am) to dusk (9pm). After 13 days, the female left the chicks alone in the box on the night of 18/19 May, this is perfectly normal but unfortunately one of the chicks died during the night. So seven chicks are hopefully going to fledge on or about Sunday 23 May (18 days after hatching).

After they fledge, the blue-tits then keep together as a family group in the local area and the young continue to be fed by the parents for several more weeks.

Home Diary 2004 Diary 2001 Archive 2001 Diary 1999 Diary 1998 Story June 1998 Diary 1997 Story June 1997

About the birds The star performers of this website are blue tits, these are small blue and yellow birds that live in woodland but have adapted to feeding and breeding in urban gardens. They are resident all year round in the UK and are seen during the winter eating the peanuts and sunflower seeds that people put out for them in their gardens. In early spring, blue tits look for nesting sites in holes of trees but they will very readily nest in artificial nestboxes. If anyone puts up a suitable nestbox in their garden in early spring, they are likely to get blue tits using it immediately.  About our location We live in Charlbury which is an Oxfordshire village at the heart of England about as far from the sea as you can get on this island. Our altitude is 122 metres above sea level. The surrounding Costswold countryside is mixed agriculture with the large expanse of Wychwood Forest in sight across the river. Wychwood Forest is an ancient oak woodland which gives its name to the local area which is part of the Royal Hunting Forest of Wychwood established by the Norman king in the 11th century.  About the nestbox Our nestbox is fitted to the wall of our wooden garage and faces east, it is surrounded by a climbing rose and clematis and is about 2 metres off the ground. Nestboxes are best sited facing east to get the warmth of the early morning sun and escape being baked by the noonday and afternoon sun. They should also be high enough off the ground and away from flat roofs to be safe from attack by cats and other predators. Some foliage around it useful to provide shade and some natural perch sites for the birds approaching the box. Do not however use nestboxes with a built-in perch because this is too handy for predator birds to perch on when attacking the nest. The nestbox is made from plywood and was bought from the RSPB. The size of the hole in the nestbox is critical (29mm diameter) and has to be small enough that larger hole nesting birds such as House Sparrows and Starlings can't use it. We have a metal plate with a matching hole fitted onto the outside of the box to prevent the hole from being enlarged, this makes it permanently suitable for blue tits and protects the nest from attack by woodpeckers. About the cat deterrents As soon as the chicks hatched, the cats could hear their cheeping and showed great interest in the nest looking up at it. Cats can be very determined and even though the wall of the garage had plastic sheeting up it to prevent a cat climbing (as in previous years) we were very anxious. We decided to try to make the general area around the nestbox as inhospitable to cats as possible. We have used five things and fortunately can report that they have been proved to work and the cats no longer walk their normal route past the nestbox on the garage wall. Cat & Dog Repeller – has a passive infra-red detector and emits a ultra sonic noise when it detects movement nearby (battery operated). Contech Water Scarecrow – has a passive infra-red detector and ejects a noisy spray of water when it detects movement nearby (battery operated and connected to a hosepipe). Cat Guard - emits a constant ultra-sonic noise (mains electricity operated). Scat-a-Cat – pungent nodules smelling of citronella scattered around the area and tied in bags to the vegetation. Silent Roar – pungent nodules soaked in lion urine scattered around the area. About the timing of the brood Blue Tits have a single brood each year in April/May at the time that coincides with the hatch of winter moth caterpillars on the oak trees. In a single brood, blue tits can lay in total the same number of eggs that a blackbird might over a span of three broods during the summer. In 1997, the blue tits took several weeks to build their nest but in 1999, they took just one. They can also adjust the number of eggs they lay and since each egg takes a day to be laid, they can have a smaller brood and catch up further. Spring seemed more advanced in 2004 than 1997 and incubation started 5 days earlier. (The Phenology website has lots of information about trends in climate change.) About the food supply Blue tits are very agile and acrobatic feeders reaching insects at the ends of twigs which can't be reached by larger and less agile birds. Blue tits have a varied diet: aphids, flies, pollen from the buds of trees, moss spore cases amongst many other things. They feed their young on high protein insects so that they grow quickly. They are very beneficial in a garden eating things that attack garden plants and can therefore be very badly affected by the use of insect sprays. They return to their young with food about every few minutes, this can amount to 300-400 mouthfuls every day over the three week period until the young fledge. After that the adults still feed their young in the local hedgerows until they are able to find their own food. The BTO say that urban blue tits might have trouble finding enough food if there aren’t enough mature trees nearby, feeding them supplementary mealworms is recommended. About the camera The camera is about the size of a matchbox and has been fitted to the inside of the lid of the nestbox. It is an infra-red camera with 6 infra-red emitting diodes, which enables the nest to be viewed without any external light, i.e. in low light conditions and at night. The composite video and audio signals are fed into a video recorder. The RF output of the video recorder is fed into the building’s internal cable system and distributed to several computers with TV capture cards. One of these computers (the nest server) uploads a picture of the nest box to a website on the Internet every sixty seconds. If the streaming link on the website is clicked then the watcher's computer requests a video stream directly from the nest server. Much of this would not be possible without broadband access in Charlbury. We were just going to install two new cameras: a colour one and replacement black and white infra-red one, but the female started occupying the box overnight and we realised we’d missed the opportunity this year. In 2001, the computer checked the image every 15 seconds and captured the image if it had changed by more than 3% compared with the previous image. This being pre-broadband, the photos were uploaded to the Web every hour. The photos captured during the previous hour were cycled through on screen every 3 seconds. All the photos were archived and the web page still shows an index of links to specific dates and times which can be chosen to cycle through that hour's worth of photos.

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