Monday, June 19, 2017

Orange tip caterpillar food plants

We have all three of the commonest food plants for orange tip butterflies in the garden - hedge garlic (Alliaria petiolata), lady's smock (Cardamine pratensis) and sweet rocket (Hesperis matrionalis), though I only encourage the last two because hedge garlic is so invasive.

This year, for the first time, I've noticed the caterpillars feeding on the developing fruits of this plant, honesty Lunaria annua.

I think they probably find it tougher to chew than the other three plants but they seem to be growing rapidly on this diet.

The only drawback, from the caterpillar's point of view, may be that they are more conspicuous on these disk-shaped fruits. When they align with the long, thin pods of the other three plants they are quite hard to spot because their countershading colour scheme works very well in those circumstances and they don't cast a bold shadow..

Saturday, June 10, 2017

Barn owls

It used to be the case that you could go for years in my part of Durham without seeing nesting barn owls. This week I've had the pleasure of watching two pairs.

The first was a bird hunting over open rough grassland, with scattered hawthorns, beside an old railway line that is now a public bridleway.

Barn owls almost seem to float across the ground, then suddenly perform a wing-over and stoop on their prey. This one struck three times before it rose with something small and furry in its talons, flew high over the trees and headed towards some old farm buildings where it must be nesting.

The sighting of the second pair was very close to home, nesting in a hollow ash tree on a farm belonging to a friend. She has farmed there for over forty years but this was the first barn owl that had ever graced them with a nest, so she was absolutely delighted. 

I spent yesterday evening watching a parent bird flying to and from the nest, hunting over the pastures amongst the cattle at sunset. Sometimes it flew right through the orchard where I was standing, no more than twenty metres away.

A magical evening, watching a truly stunning bird.

Friday, June 9, 2017

Springtails walking on water

Springtails are probably the most numerous animals in our garden composting bins. Every time I lift the lids I can see hundreds jumping around on the surface of the decaying kitchen waste and rotting garden weeds.

Recently, after heavy rain, I saw them in a new context. A container beside one bin had filled with rainwater and I noticed little pale grey patches floating on the surface.

A close look revealed that they were springtails. 

Individually these tiny animals are rather cute, so light that they barely dimple the water surface. 

Collectively, there were hundreds of them floating in huddled groups on the meniscus.

The springtails could easily escape the surface tension, using the little device in their tail called a furcula, that acts rather like a pole vaulter's pole when it's straightened, catapulting the animal into the air.

In this picture you can also see a tiny brown tick floating amongst the springtails.

How they all came to be on the water surface is a mystery.

There are more pictures of springtails here