The young birds are fed only with caterpillars, albeit lots of caterpillars! Great tits catch around ten thousand of them to feed the nest until the brood starts to fly.
The parents are constantly going back and forth to satisfy the appetite of their little ones, making almost 800 trips a day. To ensure enough caterpillars can be found, the timing of hatching is synchronised with the appearance of caterpillars in spring. This depends directly on the weather and fluctuates from year to year and faces disruption over the long-term due to global warming.
So that’s what they eat, but what about water? The chicks have to drink don’t they? So how do their parents carry water to the nest?
It’s quite simple. They don’t have to transport any. Actually, the fledglings – and birds in general – are able to store the water contained in their food and that found in the caterpillars is enough. That’s also one of the reasons why the young birds are fed only caterpillars and not seeds.
A clean nest From egg to flight ?