Thursday, December 17, 2020

Handsome heron


This very handsome heron has taken to perching on a rock just downstream of the bridge over the river Wear at Wolsingham, offering excellent views of his preening activities. The heron breeding season begins in February, so I imagine this is a prelude to February courtship.

Wednesday, December 9, 2020

Roe deer

 I often see roe deer in the distance when I'm walking in Weardale, but it's usually just bobbing white tails in the distance as they bound away amongst the trees. But these two - a mature doe and her almost full-grown fawn - were unusually cooperative and hung around long enough for me to take some pictures.

The fawn has a darker, rougher coat and smaller ears.

Wednesday, December 2, 2020

Gorse seed weevils

 Gorse can be found in bloom in every month of the year, even in the depths of winter. I don't know how many of these flowers produce seed without bumblebees and honeybees to pollinate them but I do know, from experiments I did years ago, that their pollen is viable and capable of germinating at low temperatures, close to freezing. So it may be that, with some violent buffeting from winter winds, some pollen is shaken onto stigmas and they do produce some seed.

If they do, then they may avoid seed predation by the gorse weevil Exapion ulicis, which hibernates through winter. This little beetle emerges from hibernation in spring and lays eggs on the ovary, where its grubs feed on the developing seed through the summer. They pupate as the pod ripens and adults often hatch in the pods, only to be thrown out along with any remaining seeds when the pods burst open on warm summer days.

When the autumn weather is wet some of the seed pods do not develop walls that are brittle enough to split open, so the weevils die, trapped inside. I took some old, undehisced pods home and opened a few to see if there were any dead weevils inside, and found a few live ones. 

When they fell out of the pods I thought they were dead, because they were lying on their backs with their legs curled up, but this was just thanatosis - feigning death, a predator avoidance strategy which weevils often use when danger threatens. Soon their were waving their legs in the air and rolling over onto their feet, to scuttle away across the kitchen table.

Gorse seed weevils are very effective seed predators and have been used in New Zealand and California, where gorse has been introduced and has become a noxious weed, in attempts to limit its invasive tendencies.