Wednesday, 19 February 2014

Week 5/A: Oaks, Galls and Snowdrops

Having made this blog public last week, I shouldn’t have been surprised by the almost immediate and terrifying mild sense of stage fright, and the utterly irrational fear that everything in nature would cease to be “there” for me to explore! It came as a relief, although not a surprise, that Nature was still there today.

A mid-week visit this time. The two main aims of today were to photograph the Oak at Dellfield and the Snowdrops I’d seen growing on Bulbourne Moor (across the road from B&Q). I started with the Oak, stepping out of the car to the sound of a lusty Dunnock and a male Chaffinch belting out his song. Both birds obviously getting a head start on Spring-time pursuits.

I opted for a silhouette of the Oak, with the blue sky loosely reflecting the shape of the canopy.

It occurred to me that I'd not included a close-up of the clustered buds of an Oak. So, I headed up to Preston Hill where I knew there were two mature Oaks with low-growing branches. I’ll try to follow these over the coming weeks, as the leaf buds open up.

The hedgerow along the path down to the pond was alive with Blue Tits and Great Tits. They were likely searching for food or potential nesting material, or simply keeping an eye on territory. A Green Woodpecker was calling, but I couldn’t see it, and a Buzzard was making its rounds overhead.

As I walked towards the woods, I came upon a solitary, young Oak. It still had last year’s leaves hanging precariously from it - very surprising given the strength of recent gales.

Growing out of a leaf bud was an Oak Marble Gall, about 2cm in diameter. I could pretend I knew what it was when I found it but, no, curiosity, resulting in a bit of research (rather than the proverbial cat-killing, thankfully!?!) was the answer.

It is in fact the home of the larvae of a gall wasp, or gallfly, so called because of its ability to stimulate these tissue swellings or galls on plants. They are a large group of wasps in the family Cynipinae (order Hymenoptera), whose eggs, once deposited, cleverly create their own home and food source. Each species of gall wasp produces a distinctive gall, with a particular form and in a specific location. The Oak Marble Gall is, not surprisingly, always found on Oaks and always in a leaf bud, and is created by the gall wasp Andricus kollari. It contains a high concentration of tannic acid and for centuries was an ingredient in the manufacture of iron gall ink, used for writing and dying clothes (just in case you needed a random fact to pull out at dinner parties!)

This young Oak tree wasn’t only hosting the Andricus kollari. There were signs of an additional infestation, this time on the dead leaves.

These are Silk Button Galls, created by the gall wasp species Neuroterus numismalis. They are always found on the underside of Oak leaves. Each gall contains one wasp lava and they should begin to emerge from now onwards.

On my way back to the car, I took the opportunity to photograph the flower buds of the Elm tree, showing the progress made in 3 weeks.

Next stop was Bulbourne Moor to photograph the Snowdrops.

As I walked through Two Waters Moor (west), I was amazed to come across Common Daisies (Bellis perennis) in the grass. However, having done a little reading, I discovered that it’s not unusual for this species to produce a few flowers in mild winters. An interesting fact gleaned from Wikipedia:

“Although the 'flower' may appear to consist of a yellow centre with white petals, this is not the case. Each individual "petal" is itself an individual flower, called asterales. In the centre there are also many tiny yellow flowers. The different colours and styles of flower work together in order to attract insects. This type of flower is known as a composite flower.”

Out onto Bulbourne Meadow some flooding still remains and I spied a female Great Spotted Woodpecker, picking bark off a tree trunk, perhaps looking for insects. Unfortunately, a pair of Magpies chased her off before I could get within photographic range.

Finally I came to the Snowdrops (Galanthus nivalis). Spring is most definitely taking hold.

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