The Caterpillar Service – Day Two

Yesterday I spent five hours on a public footpath overlooking a Long-Tailed Bushtits’ nest. I’m happy that I wasn’t disturbing them. They’re used to the constant traffic of people and dogs, which occasionally alarm them. They were quite happy with my presence.

Spending so long with them has given me an insight into their lives. I can hear their contact calls as they approach the nest. They often approach from over my left shoulder. They sit high up in the oak and check that the coast is clear. Any false step could give their nest away to a Carrion Crow or a Magpie. Both predators are nesting within 100 metres. Only one in six Long-Tailed Bushtit nests is successful. They live for just two years. This may be their only chance to have descendants.

They complete a small circuit of the two bordering oak trees and pause and wait awhile before they fly to a small sycamore. They flit nervously. Then they fly to an even smaller sycamore. Here’s one, caterpillar at the ready.

Then it’s off, heading towards the nest at a tremendous pace:

There’s a great mixture of invertebrate prey being brought to the nest. There are spiders, adult insects and caterpillars. Their lives are so dependent upon timing of their eggs hatching at peak caterpillar. Global heating is making that difficult, with a mis-match between food source availability and food need for many species.

Aren’t they glorious?

After delivering a beak-full of invertebrates they perch briefly on a nearby branch and then set off explosively for the nearest cover.

Sometimes I can see them carrying what looks like a bright white marshmallow in their beak as they burst from cover after visiting the nest. It’s a fecal sack from one of the chicks. That’s probably the most difficult moment to photograph and I haven’t managed it yet. Here’s one bursting from cover, but without a mouthful of poo:

I’ve only just discovered this nest. I have no idea when the eggs hatched and the chicks could be any size. I start to worry that tomorrow they might be gone.

I’ve learned so much technically from hours of practise getting in-flight shots of such a tiny target, often in difficult lighting conditions. It makes getting a simple charming perched shot seem a relief after the intensity of the dizzying speed and reactions needed for an in flight shot.

Yesterday I was delighted to discover that there were three adults feeding the chicks as part of the full Caterpillar Service. If only one in six nests is successful that leaves many adults with no chicks to support. Aunts and uncles join in the Caterpillar Service to maximise the chance of survival of their relatives’ brood.

As I’m packing up to go there’s a flurry of activity and I see there are not three, but five adults here at the same time. If this nest remains undiscovered I’m sure there will be plenty of fat, healthy chicks hidden deep in those brambles.

I’ll be back tomorrow to check. Do join us.

More Long-Tailed Bushtits