It’s a hard life

Being a blue tit is a dangerous business.

In the 1970s a study found that 17% of blue tit nests in a natural woodland setting (rather than in a garden nest box) were predated before the eggs even hatched. That number falls to 5% among clutches in a nest box. We couldn’t find anybody to confidently tell us how many blue tit nestlings survive long enough to fledge but there are lots of authorities happy to tell us that that fledging is a particularly hazardous time for baby blue tits.

Once fledged, things do not improve: about 63% of young blue tits will not survive their first year, which means that only 37% of each spring’s fledglings makes it to adulthood. That 37% lives an average 3 years but the maximum age for a blue tit as recorded from bird ringing is 10 years, 3 months and 10 days.

Sparrowhawks are probably blue tits’ major predator, closely followed by domestic cats. In almost half of the instances where a ring has been recovered from a dead blue tit, the blue tit was killed by a cat.

Sweet little birds living perilous lives.