What’s happening in the bluetit nestbox?


Blue tits are on a surprisingly precarious tightrope each spring. Nature writer Jane Adams shares the task ahead of ‘her’ Bonnie and Clyde.
Both sexes look similar, but the male blue tit is considerably brighter, especially in the blue on the head. It is thought that as they get older, they get brighter plumage with each subsequent moult. No other British tit has blue in its plumage. The breeding season varies with location and season, but generally starts in the third week of April. Though blue tits will lay repeat clutches if their first is lost, they rarely try and rear two broods.

In March, as I battled with 6ft bamboo canes in the overgrown veg patch, two blue tits scolded me from a nearby beech tree. It happens every year: they’ve chosen a nest box nailed to the side of the potting shed and as they flit back and forth, they think I’m a bit too close for comfort.
I’ve named them Bonnie and Clyde and they look glamorous in their yellow and blue feathered coats. They’re living life on the edge – their eggs must hatch at the same time as the caterpillars they catch to feed their chicks. It’s all down to timing.
In April Bonnie built the nest. Starting with a platform of moss and leaves and finishing by wiggling her body to form a nest cup where she placed tiny soft feathers. This month she’s laid an egg each day until she has a clutch of ten. Each weighs in at a whopping one gram. By the time she finished, she’d laid more than her own body weight in eggs. Now, she has her bare plucked chest (called a brood patch) resting against the eggs to incubate them. Anyday now they’ll hatch. If the weather’s good, both parents will find the caterpillars needed to appease the appetites of their hungry chicks. It’s thought that blue tits need to find 100 caterpillars a day to feed each chick, and as the youngsters can take three weeks to fledge, that’s more than 15,000 caterpillars.

The clutch size is highly variable, but usually ranges from 7-13 eggs. Clutches as large as 19 eggs, all laid by the same female, have been recorded

No wonder scientists are worried by the effect climate change will have on our native birds’ long-term survival. With spring starting earlier, temperatures rising and rain increasing, will (or can) our birds adapt? For now, I’m keeping an eye on this intrepid pair and hoping they don’t come to a sticky end like their namesakes.

Extra Fact File:
If you see bees buzzing in and out of your nest boxes, don’t panic. It’s a privilege. They’re likely to be tree bumblebees, and they often nest in bird nest boxes. Treat them with the same respect you would nesting birds. Relish having them in your garden pollinating your plants. Their lifecycle is quick, and they’ll be gone within a couple of months.

by Jane Adams


  1. Are Blue Tits having a Poor Breeding Season this Year ? Im Located in East Yorkshire . Ive a Bird Box with a Camera Inside . I first noted the Box being Inspected in Late March . Subsequently 8 Eggs were Laid . 2 of which Failed to Hatch . 2 Young Died very early on . A further 2 Died Recently at a Well Developed Stage . The Remaining 2 can only be a Day or Two from Departing the Nest Box . My Observation is that the Adults are not bringing Bugs too frequently . Has Recent Spells of Very Heavy Rain Interupted the Food Supply Chain ? I Suspect So ! Its to be Hoped the Last 2 Survive , given the Females Hard Work and Devotion !

    • Hi I am in North Aberdeenshire and also have a camera box. our blue tits laid 8 eggs all hatched but all had died within 5 days of hatching. Very sad especially as only 2 fledged last year. Anyone else had similar experiences?


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