Hello Barbara, I'm so sorry to hear the Blue Tit nestlings have died. The behaviour you describe by the adult sounds fairly normal when nesting; they often peck around the inside and outside of nestbox, shuffle around as they arrange the nesting materials and also as they do housekeeping to remove fecal sacs as the nestlings poop. It is often hard to say why precisely nestlings die and it could be due to a number of reasons; perhaps it was due to what the adults were feeding the nestlings, or then again it could be due to position of box, either overheating or too cold. If the adults are suffering a similar fate as you suggest then I think it could be more to do with the food they have eaten. You never know in the neighbourhoood if people have used poisons (for rodents for example) or other people feeding birds have old or moldy seeds or dirty feeders which carry harmful bacteria.
Nestlings can also suffer if one of the adult birds has died leaving only one to feed the hungry chicks. Each blue tit chick can eat up to 100 caterpillars a day so it takes both parent birds to keep up the feeding regime although if an adult is left on its own it will continue to feed the chicks - natures instinct. it would be hard if there was only one adult feeding 10 chicks for example and would expect some to die, although to lose all the birds it sounds due to more catastrophic reasons.
Regarding the cleaning of the box, it is illegal to do this at the moment whilst nesting season is still ongoing so I would leave it till end of August or September before you take the boxes to empy and clean them. Once again, I am very sorry as I know how upsetting it can be.
Sorry to hear that your first experience with a camera box is a sad one, it is one reason I have never bothered with one I would find it upsetting too.
One reason for them to die is usually the lack of suitable food but it certainly sounds like something is agitating her, but with not having a camera box I'm not sure if her behaviour is normal.
You haven't seen anything in the box like ants that could be agitating her?
x post with Hazel
I agree with what Hazy and Alan have written.
As it's a common question, esp regarding blue tits and robins, I thought I'd create a list (in no particular order) of what I'd consider to be the main five causes of breeding failure in a typical garden environment.
Death of parent
Predation at nest site
Disturbance/loss of nest site due to human actions
Food - Starvation/malnutrition/choking
Inappropriate siting of nest resulting in over heating, weather issues and/or collapse
Sorry if I intrude, being totally unexperienced about blue tits and related rules. But maybe the question can be valid for any similar situation: shouldn't the dead chicks be taken away? And, supposing the parents will do this unpleasant job, what if the reason of these deaths is something in the very nest, affecting all of them? Shouldn't the nest better be cleaned at once, to eventually distroy the "reason"? The tits would surely build a new one soon, as they would do in case of accident to the nest. Or am I completely wrong? Thanks for your kind and always helpful advices.
No, dead chicks should be left in situ. Blue tits are usually single brood, so a failed nest won't be re-used again this year, whether it's "cleaned" or not.
IMO, there are five primary reasons why garden nests fail. There are of course others, but I don't see how removing a failed nest would help a rare second attempt anyway.
Hi Robbo, thanks. I told you I was not an expert of Blue tits. I do not think we have them in Sardinia, surely they are not in my area, unfortunately. Now, what if the same happens to "my" sparrow nest or to another kind of bird nest, with multiple broods in a season? What shall we do? Thanks!
Hi. Got to admit I can't really answer that properly. If it was me, whatever country, I would leave the nest until Autumn. Adult birds are more than capable of tidying up themselves if needs be.