The Blues

The last few days have seen warm sunshine by day but chilly nights, meaning it has been poor for moths but good for day-flying insects. Today at Blashford Lakes I saw my first scarce chaser and downy emerald of the year and there were other dragonflies about too with reports of emperor, broad-bodied chaser and hairy dragonfly.

Most of the butterflies that over winter by hibernation as adults are getting scarce now and spring species such as orange-tip are dropping in numbers. there are a few whites around with all three of the common species, but the highlight today was the emergence of  blues. The small meadow near Ivy North hide had six or more male common blue as I went to lock up and at least three brown argus as well, the argus is brown, but an honorary “blue” all the same..

common blue male

common blue (male), freshly emerged.

The brown argus look very like small female common blue, and the male common blues will get up to chase one if it flies by, however they quickly realise their mistake and give up. The first emergences are all males and the females will follow in a day or so. The reason for this is the same as that for male migrant bird arriving just ahead of the females. Evolution will push the males to be in place and ready for the first females to arrive, it does not pay to be late, so the pressure for males to be early is greater than that on females, who can afford to wait until they know there will be males to mate with.

The spring solitary bees are starting to disappear now, many species collect pollen from just a few plants and as these cease to flower they need to wrap up their breeding cycle. I did come across one interesting species today though, it was one of the nomad bees and the smallest species of them to be found in Britain, Nomada sheppardana.

Nomada sheppardana

Nomada sheppardana on forget-me-not

Visiting flowers is something many insects have to do to feed, it may sound an unproblematic things to do, the flowers want to offer a nectar reward, or perhaps bribe might be a better description, to the insects that will pollinate them. However it is not as safe as it might sound, flowers can hide predators, especially the camouflaged crab spider which match their colour to the flowers they sit on.

crab spider with hoverfly

crab spider with hoverfly prey

The crab spider here matched the hawthorn flowers so well that I missed it and initially set up to take a picture of the hoverfly, only then did I see the spider!

It has not been a good year for ground-nesting birds so far this spring, with most lapwing and little ringed plover losing their eggs to predators. I suspect mammals at night as the ones nesting on the islands are doing much better. Or at least they were, on Thursday might all the black-headed gull on Long Spit abandoned their nests. Although I don’t know for sure I suspect that something swam out there and ate their eggs, probably a fox or a badger. These mammals are usually not that keen on swimming, but if they are hungry they will go to great lengths to get the food they want, I think small mammals, which are their preferred prey, are in short supply this year, which might be why they are seeking birds eggs more actively.

Despite a bad time for some ground-nesters the pair of oystercatcher are still doing well, with their two chicks growing well. They hatched on Long Spit, moved off to the shore near Tern hide and have now returned to Long Spit, this meant they were not out there on the night of the predator raid. So far the main gull colony on Gull Island shows no sign of being attacked and neither do the tern rafts on Ivy Lake.