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Nestwatch 2011

Derek's House

Blue Tit
Blue Tit
Blue Tit
Parus caeruleus
Meantán Gorm

General biology
Length: 12 cm.
Weight: 10-13 grams.
Wingspan: 18 - 20 cm. Life span: 2-.3 yrs

The Blue tit is the most common resident tit over most of Europe, especially in the west. They are typically woodland birds but have adapted well to living in close association with man. They are common, colourful, noisy, tame birds.

They have a multitude of local names including: Tom tit, Blue cap, Tit mouse and Blue bonnet. They are the only tit species with a blue coloration.

For a long time, tits were collectively known as tit mice. The name arose from two words: Tittr, an old Icelandic word meaning small and Mase, an old English word for small bird.

The wings are pale blue with a single white wingbar. The back is a greenish colour. The under parts are yellow with a neat dividing line on the centre of the breast. They have a blue crown and white cheeks with a black eye-stripe. The bill is short, the wings are round and short and the tail is also short.

Although woodland birds, the blue tit is one of the first birds to make use of food supplies provided in the garden and have since become a favourite of those who feed birds in the winter.

Interesting Facts

In the late 1920's in Southampton, Blue tits learned to remove the caps of milk bottles and drink from the bottle. This was to get at the cream at the top of the bottle. It's not the milk they were after. The tits lack the enzyme to digest lactose. Drinking milk in fact causes tits to suffer diarrhoea! The milk (full milk) had cream at the top. This cream has no lactose. It is digestible and is very energy rich. The habit spread to London in 1935. Many's a blue tit fell into the bottle and met it's end! With the introduction of semi-skinned and fat free milk and with the decrease of doorstep milk deliveries, this delightful activity of the blue tits has become a part of folklore.

Blue tits have yellow breast feathers. To maintain this colouring, they need to eat certain caterpillars that consume carotene loaded plant leaves. The more of these caterpillars they eat, the more intense is the yellow coloration. Females tend to choose mates with the brightest yellow breast feathers and at this time of year, you may notice courtship feeding, that is, the male bringing food (generally a fat juicy caterpillar) to the female.

The female chooses her mate and nest site. The breeding season starts about early April. In the 3 weeks before egg laying the female increases her weight by at least half (with the help of the male). As the nest takes shape, the female forms the deep cup by wriggling and turning around in it, while she continues to build up the sides. As egg laying commences, she produces almost her own weight in eggs - laying one egg a day for 12 days or so.

Incubation begins after the last egg has been laid. Egg laying starts generally the last week of April. Generally blue tits have only one clutch. This is set to coincide with the abundance of caterpillars of a particular insect species on which they depend.

The eggs take about 14 days to hatch. After hatching, the adults will make about 400 daily visits between them for the first few days. This number will rise to 1,000 or more visits per day prior to the young leaving the nest. They collect the caterpillars mostly from Oak leaves. At this time, the adults feed on only the smallest caterpillars themselves, leaving the largest ones (with the most energy) for the babies in the nest. They are extremely effective pest controllers in the garden.

Nesting success is high once the young birds remain within the nest, but this all changes after the young leave the nest. Anything up to 90% mortality can now be expected. The young fledge at about 20 days and the main predators are sparrow hawks, magpies and especially cats.

Some things you may not know...

- Blue Tits nest in holes on trees or in walls but will readily use other, man-made objects. In Ireland at the moment, birds are nesting in several post-boxes and in traffic lights at busy junctions.

-Blue Tits seem to have benefited from the 'smoking ban'...many bars have erected wall mounted ash trays for their smoking customers and Blue Tits have discovered these. In Britain, many pubs have had to ask their customers not to stub out their cigarettes in these ashtrays because families of Blue Tits have settled into these mad-made nest holes!

- In France it has been discovered that when Blue Tits nest in places that have strong odours, they will frequently create 'perfumed nests' by bringing lavender and mint leaves into the nest creating an aromatic environment for their young (only French birds would do this!!!)

- Blue Tits have only one family each year and invest all of their time and energy into raising that one brood. If food is scarce or the weather bad, many chicks will perish. Blue Tits are small, short-lived birds so, for many birds, they may only have one opportunity in their lives to pass on their genes.

- A pair of Blue Tits will feed as many as 15,000 flies or caterpillars to their young in a three week period....no need for pesticides when you have a pair of Blue Tits around.

- Unlike many bird species, both male and female are almost identical...the male is slightly brighter, especially on his crown. That blue crown glows in ultra-violet light and, remarkably, Blue Tits see the world in ultra-violet.

- When a chick leaves the nest, it will be only three weeks old. It will be looked after for about two weeks but at the tender age of just five weeks old; it will have to fend for itself.

- In the time when 'the milkman' delivered bottles of milk to our doorsteps, Blue Tits discovered that if you pierce the top of the milk bottle, you can get a drink of the cream which always came to the top. This was first done in Britain back in the 1940's and by the late 1960's Blue Tits in Ireland had learned how to do this. It is considered that this knowledge was passed on through the generations and was a 'learned behaviour'.

- Blue Tits are considered to be very intelligent and have solved complex obstacles and puzzles in order to get to peanuts in feeders

Eric's Diary
Derek's Diary Read Derek's diary of the Blue tits that have taken up residence in his garden.
AirSpeed Technical support for Nestwatch 2011 provided by AirSpeed.
Birdwatch Ireland
BirdWatch Ireland Conservation partners for Nestwatch 2011.