There was a partial eclipse of the sun this morning, starting at about 10 am, peaking at 11.04 and finishing just after noon. An eclipse of the sun occurs when the moon passes between the earth and the sun. I had some eclipse glasses which I shared with garden visitors, as you must never look directly at the sun. I covered my camera lens with sun filter film which cuts out 99.999% (that’s what it says on the info in German) of the light and took some photos. 28% of the sun was occluded at peak, like a large bite taken out of a glowing biscuit.
I have been observing how the heat builds up in our new shelter. It is due to the greenhouse effect, the actual one, not the analogous one that causes climate change . Climate change is due to build up of heat absorbing gases in the atmosphere, mostly C02 but increasingly methane (CH4). We need some of this. If there were no carbon dioxide in the atmosphere at all, it has been estimated that the average world temperature would be minus 18 degrees. So some climate change gases, but can we call it a halt.
The build up of heat in our shelter has a different mechanism. Heat travels from hot to cold in three ways: radiation, convection and conduction. At night, conduction through the walls loses the heat gained during the day, and temperature inside becomes the same as outside. But, as the sun rises, heat enters the shelter by radiation, the warmth from the sun’s rays. The warmth causes convection currents, which is another way of saying warm air rises. Without a roof, the warm air would mingle with cold air, lose its heat and sink. But we have a roof. So the hot air sits under it, slowly losing its heat as it is conducted through the plastic to the outside. More slowly than without a roof, so the heat builds up inside. The highest temperature I have seen inside has been 28 degrees, ten degrees hotter than outside.
Leaves are coming on the trees. The first in leaf are the willow and the birch. The new leaves are light green; the colour will darken over the summer as they mature, becoming a deep green in early autumn. Both the willow and the birch have catkins. The birch has male and female on the tree, the male from last summer, the female has come in the last week or so. The tree is monoecious, meaning one tree is sufficient for its reproduction. The willow by the greenhouse has only male catkins. It is dioecious, needing two trees, this one with male catkins and another with female catkins. Only the female bearing tree will carry seeds, pollinated from the male by the wind.
The tadpoles have hatched, three weeks since the first spawn appeared. Most are in a dense, black layer. If you look closely, you can see wriggling bodies. They will need to disperse, those that don’t will starve. Most will. A few already have. There’s a small cluster of spawn, the eggs within round, showing no sign of growth. This spawn has not been fertilised. The jelly and the eggs will be eaten by the free tadpoles and other predators such as back swimmers.
The tadpole at this stage in its cycle is simply an eating machine. That’s more or less all it does, while it slowly metamorphises. Though, it will swim away from movement; its only defence from the myriad dangers facing it on its journey to become an adult frog, a destination few will arrive at. A vast cull will take place, which is the reason a female frog lays so many eggs. I can’t be quite dispassionate at this yearly toll, though the tadpoles have no idea what will likely befall them. It is survival of the fittest, or perhaps the luckiest. One hell of a lottery, with so few winners.
The magnolia lost its blossoms in a week. There were quite a few, maybe 20, pure white flowers, the size of old fashioned lightbulbs. But wind and rain hits them hard and they were gone in no time.
I hear a great tit though I can’t see it. I call it the rusty scissors bird, as it has that sort of squeak. Others say it is reminiscent of a squeaky gate. There are blue tits, parakeets and sparrows on and off in the garden. I see a pigeon drinking from the pond. They are also the most frequent visitors to our bird feeders. I have seen them eating the buds on the sycamore. Flying is arduous for these big birds; they need a lot of feeding.