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.

 

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30 Days Wild – Day 15: Trying to Impress

I was out on the eastern side of Ibsley Water with the volunteers this morning to clear the areas we cut and which are grazed by ponies of ragwort. It is toxic to animals, but they will usually not eat when it is growing, however they will if it is cut and gets mixed with grass or hay. At one time it was one of the commonest plants in this area but now it is much reduced and overall the grassland is looking much better, with quite a good range of species. A couple of highlights this morning were several patches of corky-fruited water-dropwort.

IMG_1455

corky-fruited water-dropwort

Corky-fruited water-dropwort is an Umbellifer, one of the carrot family and is very attractive to insects, this one had lots of pollen beetles on it. It is quiet frequent in unimproved grasslands in a swathe roughly south of the M4, so it is pleasing to see it at Blashford where the grassland is still recovering from the ravages of mineral extraction. Another find was knotted clover, a plant of dry sandy places, often near the coast, I am not sure if I have found it at Blashford previously.

knotted clover

knotted clover

At lunchtime I tried the pheromone lures for clearwing moths again, completely without success. However I did spot a handsome black-and-yellow longhorn beetle.

black-and-yellow longhorn beetle Rutpela maculata

black-and-yellow longhorn beetle Rutpela maculata.

After doing various odd jobs in the afternoon I went to lock up the hides and found a pair of crab spiders on a hemlock water-dropwort flower head, The male is quite different from the female and a lot smaller so he has to tread carefully if he is not going to get eaten.

crab spider pair

crab spider pair

It seemed it was not only the spiders that were making plans, on a nearby ox-eye daisy I saw a female hoverfly Eristalis horticola, with a male hovering low over her and darting from side to side. I am not sure if she was impressed but he was trying hard to dazzle her with his advanced hovering skills.

Eristalis horticola pair

Eristalis horticola pair

I also found another slime mould, on the same log as the one the other day, although this was clearly a different species.

slime mould

slime mould

The only new bird sighting of note today was of a first summer little gull as I locked Tern hide. It was pleasing to see that the single oystercatcher chick from gull island has fledged and that the remaining one near Tern hide is close to doing so. In additions the single large lapwing chick is also close to flying and two of the smaller ones are still going strong. Even better was a sighting of two well grown little ringed plover chicks today. On Ivy Lake the common tern chicks are growing well and most broods seem to still be of three chicks.

30 Days Wild – Day 9: Send in the Troops

Despite a bit of a stutter in the summer weather this week the season still advances and Day 9 of 30 Days Wild saw the first common tern chicks on the rafts on Ivy Lake. I think they probably hatched couple of days ago. One pair was a few days ahead of the main group so I am expecting a lot of chicks to hatch next week. Common tern almost invariably lay three eggs, so if they all hatch our 36 pairs will have about 100 chicks between them, so fingers crossed for a successful season.

I saw the terns from Ivy South hide where the grass snake were on show, basking on the stump below the hide.

two grass snakes on the stump

Snakes on the stump

The most significant sightings of the day though were once again of insects. I will always try to make a quick check of the hemlock water-dropwort at lunchtime, this plant is very attractive to nectaring insects and amongst these can be some rarer species. In particular it attracts bees, hoverflies and soldierflies. Blashford is a good site for bees, many of which use the dry lichen heath for nesting. Equally the wetland habitats are the home to many hoverflies and especially soldierflies, including some nationally rare species. So I was very pleased to spot at least one ornate brigadier soldierfly (Odontomyia ornata), a species that we see at Blashford every couple of years or so and has, so far, not been found anywhere else in Hampshire. I then spotted a second species, the black colonel (Odontomyia tigrina), slightly more often recorded but still quite rare, this one at least allowed me to take a picture.

Odontomyia tigrina female

Black colonel soldierfly (Odontomyia tigrina), female on hemlock water-dropwort.

However visiting flowers to feed, as these insects must do, is a risky business, there are predators lying in wait, in particular crab spiders.

crab spider with bee prey

Crab spider with bee as prey

Elsewhere on the reserve the three smaller lapwing chicks are still surviving in front of Tern hide along with the single larger one, I did not see the oystercatcher chicks and I suspect they may have lost one late on Thursday. We will see what next week brings.

Brilliant Volunteers

As I have noted many times on this blog, Blashford Lakes would not be anything like as good a site without the invaluable input from our great volunteer team. Our volunteers help out with a range of tasks and do some projects in their entirety.

Over the last week we have had volunteer educators helping with school groups river dipping in the rain, reptile and butterfly surveyors, office administration and our Tuesday and Thursday working parties.

The rarest habitat at Blashford Lakes is the Lichen Heath, perhaps because of its industrial origin it is not actually designated, but it is home to many nationally rare species which form an assemblage which needs looking after.

lichens

Lichen Heath close-up

The importance of the area rests on it having very low nutrients, but over time nutrients fall from the sky and collect in the upper layers of the soil as mosses, lichens and small plants die. The obvious conclusion is that it will slowly disappear and turn into nutrient poor acid grassland. So how to keep some areas to true Lichen Heath? The answer is probably to strip off the surface layer and get down to the bare sandy surface and let it colonise once more. This seems very drastic and it feels wrong to be stripping off what is still a diverse sward with lots of interesting species. We started doing this in a small way on Tuesday, doing six small trial plots which we can monitor, if it looks a good technique we can extend it more widely in the years to come.

Lichen heath before

Lichen heath before surface stripping

Lichen heath after

Lichen heath after surface stripping

We chose sites where there were small bramble or birch trees that needed removing anyway and piled up the material on the northern side of the scraped area to provide some variation in the surface topography and potentially warm nesting sites for the many species of bees, ants, wasps etc. that call the heath home.

The rain this last week is what allowed us to work on the heath as it meant the lichens absorbed water and so could be walked on gently, in dry conditions they would just crumble to dust under foot, which is why we ask visitors not to walk on it. Even in wet conditions it is intolerant to trampling so we do as little as possible out there. So it was a treat whilst we were there to see some of the special species that grow on the heath including the two rare bird’s-foot trefoils.

hairy bird's foot

Hairy bird’s-foot trefoil

 

slender bird's foot

slender bird’s-foot trefoil

On Thursday the volunteers were back on the task of clearing Himalayan balsam and pink purslane from along the Dockens Water. These two invasive alien species can muscle out native species, but can be controlled by pulling them up to prevent seeding. After several years of doing this we have made great progress and balsam is now no more than occasional where once it was the dominant plant. Along the way when doing such tasks we come across other things of interest, one such find was a mating pair of lime hawk-moth.

lime hawk pair mating

Lime-hawk moth pair

Some discoveries though are less welcome and one such was an American skunk cabbage plant, the first I have ever heard of along the Dockens Water. This plant has been a big problem in wetland sites across the New Forest and the subject of an eradication program, so finding it here is a worry. I suspect that somewhere up stream someone has it planted around their pond and the seeds are escaping to grow in the wild.

skunk cabbage

skunk cabbage, a young plant without the huge leaves and yellow flower that attracts water-gardeners.

Our last chance find was made by Geoff, one of our most regular volunteers who photographed this crab spider which had ambushed a bee visiting a daisy flower.

spider

Crab spider with bumble-bee prey on ox-eye daisy.

I will endeavour to do a wildlife update for the week later, I know we have received a number of fabulous photographs from visitors.

 

30 Days Wild – Day 13

Nearly caught up! Day 13, a Monday and a wet one at that. I was leading a guided walk at Blashford in the morning and was a little concerned that we might struggle to see very much. I need not have worried, we started at the Centre with a quick look at the moths and then, as the school group were elsewhere, checked out the tanks and trays of creatures caught in the pond. Before we even got around to seeing any birds we had clocked up several dozen species and, thanks to the shelter, we had not even got wet.

As often seems to be the case the weather improved a bit later in the day and before going to lock up I checked out the sides of the Centre pond looking for dragon and damselflies. There were lots of newly emerged damselflies all around the pond edge with some stems having several exuviae showing how many had already emerged.

newly emerged

newly emerged damselfly

exuviae

signs of a mass emergence

The masses of immobile soft-bodied insects attract predators and the local robin was having a feast. Even when they are able to fly they need to be wary about where they land as there are ambushes all over the place. I spotted this crab spider lurking on a hemlock water-dropwort flower head, when I first saw it she was just finishing off a common blue damselfly.

crab spider

crab spider lurking