Progress Against an Invader

Thursday at Blashford is volunteer day and we had a good turn out of fourteen for our first Himalayan balsam pull of the year. After many years of pulling this plant we have very significantly reduced the population and it is nowhere the dominant plant. The advantage of doing the first sweep early in the season is that we remove a significant number of plants but also get an idea of where the main problem areas are and so where to concentrate on our later visit. Pleasingly we found no more than a couple of hundred plants on about half the length of the stream, enough to suggest that there is still a seed source upstream  somewhere but not so many that it is having a serious impact on native wildlife.

The common terns are finally taking some interest in the rafts on Ivy Lake, although they are still not really taking control of any in numbers sufficient to deter the black-headed gulls. I tried putting out another raft during the afternoon in the hope that a new one might tempt them in. The gulls often just loaf around on the rafts, but have the annoying habit of bringing reeds and sticks and leaving them scattered  over the surface. I suspect they are mostly young adults, as the older birds started nesting a couple of weeks ago, a few may eventually build a proper nest, but in the meantime their practice efforts are putting off the terns.

Generally things were quite across the reserve, most of the birds are now nesting or getting ready to do so. Our visitor form North America, the Bonaparte’s gull is still to be seen, although it does not now attract more than the occasional admirer. I did manage to get a slightly better picture of it, which does show a couple of the differences from black-headed gull. You can see the slightly smaller size and overall thinner, more “pointed” look. Now that it is getting a summer plumage hood you can also see that this is blacker than that of black-headed gull, which is actually chocolate brown.

Bonaparte's gull

Bonaparte’s gull (right)

A very noticeable feature of the past week has been the huge increase in the numbers of damselflies around the reserve. Common blue and azure damselflies are now out in numbers, but the large red damselfly, typically the commonest spring species is very hard to find, perhaps due to the very poor April weather last year.

 

 

Bank Holiday blues

Welcome, from a soggy Blashford Lakes Reserve. As is customary we have another damp and dismal Bank Holiday Monday (10mm of rain overnight and it hasn’t stopped raining all day), but there are a few folk here making the most of the situation.

Not terribly inspiring for bird watching and most self respecting insects are keeping well out of sight today, so I’ll just share a few pictures, taken last Friday, when covering the Butterfly Survey transect on the south of the Reserve.

Green-veined white butterflies were the most common on the transect and arguably THE most common butterfly in the U.K. with a wide geographic range (absent only from Orkney and Shetland) and having two or even three broods (in good years).  An innocuous butterfly, its caterpillars don’t damage cultivated cabbages, unlike their close cousins the large white  and small white, but lay their eggs on wild relatives of these plants. An active butterfly its quite difficult to identify from small white when in flight, I’m guessing that many ‘non-butterfliers’  probably wouldn’t even have heard of them – I know I hadn’t before taking more interest in these insects.

Most common butterfly - Green-veined White

Most common butterfly – Green-veined White

Green-veined white butterflies are very much a species of damp and marshy places near hedgerows and woodland edges, so the Reserve is ideal habitat for them – especially today.

Overall the number of butterflies to be seen has dropped off lately as the temperature falls  and sunshine has decreased with only 21 butterflies of four/five species ( including ‘unknown’ White) seen last Friday, although I believe the transect on the north side of the Reserve was more productive. The brightest and  most colourful was this Comma.

Comma - so named from the tiny white 'comma shaped' mark on the underside of the hind wing

Comma – so named from the tiny white ‘comma shaped’ mark on the underside of the hind wing

The common name of this butterfly, and even the scientific name Polygonia c-album, refer to this tiny mark (if my rusty knowledge of Latin is correct c-album = ‘ white c’), but it’s really quite inconspicuous unless you know to look for it.  I guess the naming dates back to the time when collectors could study these things at their leisure as it was  ‘O.K.’ to catch these beautiful insects and handle them, before killing and mounting them in collections

In greater profusion than all the butterflies were common blue damselflies which were just about everywhere, gently skimming over the tops of shrubbery and settling, usually briefly, before being disturbed by another damselfly. The males were most conspicuous, with their electric blue colouration,  whilst the females were difficult to pick out, especially if motionless as they stayed perched up.  I’ll admit that I find it easier to identify the species of a male damselfly, like ducks as opposed to drakes, the females are more drably marked.

Dragonflies and damselflies are spectacularly visual insects, the relative size of their eyes is a bit of a give-a-way, so I’m guessing that males can easily identify their prospective mating partners from a mixed assortment of, to us, similar looking females of other species.  As a safeguard to prevent cross breeding  I understand that the claspers (anal appendages) on a male can only latch on successfully to the neck of a female of the same species to create the mating position called the ‘heart’ or ‘cartwheel’ position.  Whilst so engaged they are easier to photograph as they seem somewhat ‘distracted’ and less likely to fly off suddenly – can’t think why!

pair of common blue damselflies

pair of common blue damselflies in cartwheel position

Dragonflies were also out and about, hopeless trying to photograph them whilst flying (the dragonflies – not me!) with my little camera, but when they hang-up briefly there’s a chance of a quick shot.   Missed the southern hawker, but this migrant hawker was more obliging.

Migrant hawker

Migrant hawker

Common darter are living up to their name, by a) being quite common (20 plus seen easily – don’t know how many we missed) and  b) perching up and ‘darting’ out before returning to the same perch, making them relatively easy to photograph.

Common darter

Common darter

The butterfly transect should notionally take about an hour and a half, but we managed to stretch it to two hours, having been ‘distracted’ by some quite delicious blackberries along the way. Whilst engaged in this activity a strange bug hopped onto my hand and demanded to have it’s picture taken.

Dock bug?

Dock bug?

Searching the literature – and online – I think its a dock bug (Coreus marginatus) , though not a fully grown one, as these appear to have a more definite darker patch on their abdomen.  One of the family ‘Leatherbugs’ of which there are eleven species in the U.K. and five in the new Forest (Paul D. Brock : A photographic guide to Insects of the New Forest) this is apparently the most common and easily found.

I’ll close with an update from the rain gauge – 22mm (nearly an inch in real terms)  and rising!!

 

In the Balance

Bird News: Ibsley Waterhouse martin c1500. Ivy Lakecommon sandpiper 1.

The last couple of days have seen huge numbers of house martins over Ibsley Water, yesterday something over 2000 and today at least 1500. In addition yesterday there were several hundred swift and sand martin and a few swallows. Today there were fewer swifts and so few swallow that it took me several minutes to see one. The only other bird of any real note that I saw during opening up the hides was a common sandpiper with the common terns and black-headed gulls on the rafts on Ivy Lake. The black-headed gulls look quite settled but one pair were getting a very hard time from the common terns today so perhaps they will get driven off in the end as they were last year.

Although there was a frost overnight the day dawned sunny and this was good to see as I was leading a course on invertebrates at Blashford today. It was still quite cold and this kept the insects in hiding, in fact the recent cold weather has set the season well back, I still have not seen any species of dragonfly and the moth catch was reduced to just three this morning. Looking for sun-loving species like hoverflies was a waste of time so we were restricted to largely sweep netting and log-rolling. Despite this we did not have a bad day and saw a few good species and a lot that were new to the participants. The sunny spells did tempt out a few damselflies including azure, blue-tailed and beautiful demoiselle. we are repeating the course in June and July when it will surely be warmer, won’t it? I snapped this ant, which did not get identified to species level, while we were out and about hunting inverts.

ant Myrmica spp.

Although the highlight from the Tern hide were the martins I was distracted by a black-headed gull on one of the near posts it was preening and eventually went for a particularly daring scratch manoeuvre, probably only something to attempt on a calm day.

black-headed gull scratching

 

black-headed gull, preening